Multidisiplinary approaches in ergonomics :: essays research papers

In the redesign of an assembly or packing line a multidisciplinary team of medical and technical representatives work collectively to identify, evaluate, and control risks to employees whilst maintaining productivity for the company concerned. Those who contribute to the redesigning of industrial equipment, such as assembly or packing lines, include professionals with a variety of expertise, including the occupational health nurse, occupational therapist, occupational hygienist, physiotherapist, ergonomist, human resource staff, and the design engineers. The role of each representative from the seven groups will often overlap, the objective for all however is to identify health hazards in the workplace and eliminate them, protecting workers from the primary sources of health risks whilst designing proficient equipment that makes the best of the workers potential without exceeding their physical and psychological capacity. The role of the occupational health nurse is to provide nursing care in the work environment to employees and others with injury and illness. The nurse gives emergency care, prepares accident reports, and arranges further treatment or care if required. They also assess work environments for potential or actual health problems. Their contribution to redesigning an assembly or packing line would be in the form of supplying valuable data from incident and accident reports that identifies hazards relating to the existing equipment (Lloyd, 2002; Quinlan & Bohle, 1991; Sanders & McCormick, 1993). Responsible for preventative modification of the working environment has generally been assigned to occupational hygienists, engineers, and ergonomists. Occupational hygiene is an environmental science concerned with physical, chemical, and biologic hazards to the worker. The occupational hygienists recognize that safe and healthy working conditions enhance the quality of life for the people involved and contribute to productivity. Broken into three phases, identification, evaluation, and control, the occupational hygienist collects information from a variety of sources by breaking the overall work area into component processes, identifying hazards associated with each process. They will then evaluate each identified hazard by assessing the level of risk involved. With hazards identified and the risks evaluated a control strategy is designed to minimise exposure to acceptable levels. Engineering control strategies aim to prevent illness and disease by the modification of tools, equip ment and processes (Lloyd, 2002; Sanders & McCormick, 1993; Quinlan & Bohle, 1991). Similarly, ergonomics is an expert technical approach. The scientific study of the physical relationship between people, the equipment they use and the environment they work in. Their role is to optimise the relationship between worker and equipment by modifying the working environment (Quinlan & Bohle, 1991).

Ansys Tutorial Release 12.1

 ® ANSYS Tutorial Release 12. 1 Structural & Thermal Analysis Using the ANSYS Release 12. 1 Environment Kent L. Lawrence Mechanical and Aerospace Engineering University of Texas at Arlington SDC PUBLICATIONS www. SDCpublications. com Schroff Development Corporation Visit the following websites to learn more about this book: ANSYS Tutorial 2-1 Lesson 2 Plane Stress Plane Strain 2-1 OVERVIEW Plane stress and plane strain problems are an important subclass of general threedimensional problems. The tutorials in this lesson demonstrate:  ¦Solving planar stress concentration problems. Evaluating potential inaccuracies in the solutions.  ¦Using the various ANSYS 2D element formulations. 2-2 INTRODUCTION It is possible for an object such as the one on the cover of this book to have six components of stress when subjected to arbitrary three-dimensional loadings. When referenced to a Cartesian coordinate system these components of stress are: Normal Stresses ?x, ? y, ? z Shear Stresses ? xy, ? yz, ? zx Figure 2-1 Stresses in 3 dimensions. In general, the analysis of such objects requires three-dimensional modeling as discussed in Lesson 4.However, two-dimensional models are often easier to develop, easier to solve and can be employed in many situations if they can accurately represent the behavior of the object under loading. 2-2 ANSYS Tutorial A state of Plane Stress exists in a thin object loaded in the plane of its largest dimensions. Let the X-Y plane be the plane of analysis. The non-zero stresses ? x, ? y, and ? xy lie in the X – Y plane and do not vary in the Z direction. Further, the other stresses (? z,? yz , and ? zx ) are all zero for this kind of geometry and loading.A thin beam loaded in its plane and a spur gear tooth are good examples of plane stress problems. ANSYS provides a 6-node planar triangular element along with 4-node and 8-node quadrilateral elements for use in the development of plane stress models. We will use both triangles and qua ds in solution of the example problems that follow. 2-3 PLATE WITH CENTRAL HOLE To start off, let’s solve a problem with a known solution so that we can check our computed results as well as our understanding of the FEM process. The problem is that of a tensile-loaded thin plate with a central hole as shown in Figure 2-2.Figure 2-2 Plate with central hole. The 1. 0 m x 0. 4 m plate has a thickness of 0. 01 m, and a central hole 0. 2 m in diameter. It is made of steel with material properties; elastic modulus, E = 2. 07 x 1011 N/m2 and Poisson’s ratio, ? = 0. 29. We apply a horizontal tensile loading in the form of a pressure p = -1. 0 N/m2 along the vertical edges of the plate. Because holes are necessary for fasteners such as bolts, rivets, etc, the need to know stresses and deformations near them occurs very often and has received a great deal of study.The results of these studies are widely published, and we can look up the stress concentration factor for the case s hown above. Before the advent of suitable computation methods, the effect of most complex stress concentration geometries had to be evaluated experimentally, and many available charts were developed from experimental results. The uniform, homogeneous plate above is symmetric about horizontal axes in both geometry and loading. This means that the state of stress and deformation below a Plane Stress / Plane Strain 2-3 orizontal centerline is a mirror image of that above the centerline, and likewise for a vertical centerline. We can take advantage of the symmetry and, by applying the correct boundary conditions, use only a quarter of the plate for the finite element model. For small problems using symmetry may not be too important; for large problems it can save modeling and solution efforts by eliminating one-half or a quarter or more of the work. Place the origin of X-Y coordinates at the center of the hole. If we pull on both ends of the plate, points on the centerlines will move al ong the centerlines but not perpendicular to them.This indicates the appropriate displacement conditions to use as shown below. Figure 2-3 Quadrant used for analysis. In Tutorial 2A we will use ANSYS to determine the maximum horizontal stress in the plate and compare the computed results with the maximum value that can be calculated using tabulated values for stress concentration factors. Interactive commands will be used to formulate and solve the problem. 2-4 TUTORIAL 2A – PLATE Objective: Find the maximum axial stress in the plate with a central hole and compare your result with a computation using published stress concentration factor data.PREPROCESSING 1. Start ANSYS, select the Working Directory where you will store the files associated with this problem. Also set the Jobname to Tutorial2A or something memorable and provide a Title. (If you want to make changes in the Jobname, working Directory, or Title after you’ve started ANSYS, use File > Change Jobname or Di rectory or Title. ) Select the six node triangular element to use for the solution of this problem. 2-4 ANSYS Tutorial Figure 2-4 Six-node triangle. The six-node triangle is a sub-element of the eight-node quadrilateral. 2.Main Menu > Preprocessor > Element Type > Add/Edit/Delete > Add > Structural Solid > Quad 8node 183 > OK Figure 2-5 Element selection. Select the triangle option and the option to define the plate thickness, otherwise a unit thickness is used. 3. Options (Element shape K1) > Triangle, Options (Element behavior K3) > Plane strs w/thk > OK > Close Plane Stress / Plane Strain 2-5 Figure 2-6 Element options. 4. Main Menu > Preprocessor > Real Constants > Add/Edit/Delete > Add > OK Figure 2-7 Real constants. Enter the plate thickness of 0. 01 m. ) >Enter 0. 01 > OK > Close Figure 2-8 Enter the plate thickness. 2-6 ANSYS Tutorial Enter the material properties. 5. Main Menu > Preprocessor > Material Props > Material Models Material Model Number 1, click Structural > Line ar > Elastic > Isotropic Enter EX = 2. 07E11 and PRXY = 0. 29 > OK (Close the Define Material Model Behavior window. ) Create the geometry for the upper right quadrant of the plate by subtracting a 0. 2 m diameter circle from a 0. 5 x 0. 2 m rectangle. Generate the rectangle first. . Main Menu > Preprocessor > Modeling > Create > Areas > Rectangle > By 2 Corners Enter (lower left corner) WP X = 0. 0, WP Y = 0. 0 and Width = 0. 5, Height = 0. 2 > OK 7. Main Menu > Preprocessor > Modeling > Create > Areas > Circle > Solid Circle Enter WP X = 0. 0, WP Y = 0. 0 and Radius = 0. 1 > OK Figure 2-9 Create areas. Plane Stress / Plane Strain 2-7 Figure 2-10 Rectangle and circle. Now subtract the circle from the rectangle. (Read the messages in the window at the bottom of the screen as necessary. ) 8.Main Menu > Preprocessor > Modeling > Operate > Booleans > Subtract > Areas > Pick the rectangle > OK, then pick the circle > OK (Use Raise Hidden and Reset Picking as necessary. ) Figure 2-11 Geo metry for quadrant of plate. Create a mesh of triangular elements over the quadrant area. 9. Main Menu > Preprocessor > Meshing > Mesh > Areas > Free Pick the quadrant > OK Figure 2-12 Triangular element mesh. Apply the displacement boundary conditions and loads to the geometry (lines) instead of the nodes as we did in the previous lesson.These conditions will be applied to the FEM model when the solution is performed. 10. Main Menu > Preprocessor > Loads > Define Loads > Apply > Structural > Displacement > On Lines Pick the left edge of the quadrant > OK > UX = 0. > OK 2-8 ANSYS Tutorial 11. Main Menu > Preprocessor > Loads > Define Loads > Apply > Structural > Displacement > On Lines Pick the bottom edge of the quadrant > OK > UY = 0. > OK Apply the loading. 12. Main Menu > Preprocessor > Loads > Define Loads > Apply > Structural > Pressure > On Lines.Pick the right edge of the quadrant > OK > Pressure = -1. 0 > OK (A positive pressure would be a compressive load, so we use a nega tive pressure. The pressure is shown by the two arrows. ) Figure 2-13 Model with loading and displacement boundary conditions. The model-building step is now complete, and we can proceed to the solution. First, to be safe, save the model. 13. Utility Menu > File > Save as Jobname. db (Or Save as †¦. ; use a new name) SOLUTION The interactive solution proceeds as illustrated in the tutorials of Lesson 1. 14. Main Menu > Solution > Solve > Current LS > OKThe /STATUS Command window displays the problem parameters and the Solve Current Load Step window is shown. Check the solution options in the /STATUS window and if all is OK, select File > Close In the Solve Current Load Step window, select OK, and when the solution is complete, Close the ‘Solution is Done! ’ window. POSTPROCESSING We can now plot the results of this analysis and also list the computed values. First examine the deformed shape. 15. Main Menu > General Postproc > Plot Results > Deformed Shape > Def. + Undef. > OK Plane Stress / Plane Strain 2-9 Figure 2-14 Plot of Deformed shape.The deformed shape looks correct. (The undeformed shape is indicated by the dashed lines. ) The right end moves to the right in response to the tensile load in the X direction, the circular hole ovals out, and the top moves down because of Poisson’s effect. Note that the element edges on the circular arc are represented by straight lines. This is an artifact of the plotting routine not the analysis. The six-node triangle has curved sides, and if you pick on a mid-side of one these elements, you will see that a node is placed on the curved edge. The maximum displacement is shown on the graph legend as 0. 2e-11 which seems reasonable. The units of displacement are meters because we employed meters and N/m2 in the problem formulation. Now plot the stress in the X direction. 16. Main Menu > General Postproc > Plot Results > Contour Plot > Element Solu > Stress > X-Component of stress > OK Use PlotCtrls > Symbols [/PSF] Surface Load Symbols (set to Pressures) and Show pre and convect as (set to Arrows) to display the pressure loads. Figure 2-15 Surface load symbols. Also select Display All Applied BCs 2-10 ANSYS Tutorial Figure 2-16 Element SX stresses.The minimum, SMN, and maximum, SMX, stresses as well as the color bar legend give an overall evaluation of the ? x (SX) stress state. We are interested in the maximum stress at the hole. Use the Zoom to focus on the area with highest stress. (Your meshes and results may differ a bit from those shown here. ) Figure 2-17 SX stress detail. Plane Stress / Plane Strain 2-11 Stress variations in the actual isotropic, homogeneous plate should be smooth and continuous across elements. The discontinuities in the SX stress contours above indicate that the number of elements used in this model is oo few to calculate with complete accuracy the stress values near the hole because of the stress gradients there. We will not accept this stress solu tion. More six-node elements are needed in the region near the hole to find accurate values of the stress. On the other hand, in the right half of the model, away from the stress riser, the calculated stress contours are smooth, and SX would seem to be accurately determined there. It is important to note that in the plotting we selected Element Solu (Element Solution) in order to look for stress contour discontinuities.If you pick Nodal Solu to plot instead, for problems like the one in this tutorial, the stress values will be averaged before plotting, and any contour discontinuities (and thus errors) will be hidden. If you plot nodal solution stresses you will always see smooth contours. A word about element accuracy: The FEM implementation of the truss element is taken directly from solid mechanics studies, and there is no approximation in the solutions for node-loaded truss structures formulated and solved in the ways discussed in Lesson 1.The continuum elements such as the ones for plane stress and plane strain, on the other hand, are normally developed using displacement functions of a polynomial type to represent the displacements within the element, and the higher the polynomial, the greater the accuracy. The ANSYS six-node triangle uses a quadratic polynomial and is capable of representing linear stress and strain variations within an element. Near stress concentrations the stress gradients vary quite sharply. To capture this variation, the number of elements near the stress concentrations must be increased proportionately.To obtain more elements in the model, return to the Preprocessor and refine the mesh, first remove the pressure. All elements are subdivided and the mesh below is created 17. Main Menu > Preprocessor > Loads > Define Loads > Delete > Structural > Pressure > On Lines. Pick the right edge of the quadrant. Main Menu > Preprocessor > Meshing > Modify Mesh > Refine At > All (Select Level of refinement 1. ) Figure 2-18 Global mesh refineme nt. 2-12 ANSYS Tutorial We will also refine the mesh selectively near the hole. 18.Main Menu > Preprocessor > Meshing > Modify Mesh > Refine At > Nodes. (Select the three nodes shown. ) > OK (Select the Level of refinement = 1) > OK Figure 2-19 Selective refinement at nodes. (Note: Alternatively you can use Preprocessor > Meshing > Clear > Areas to remove all elements and build a completely new mesh. Plot > Areas afterwards to view the area again. Note also that too much local refinement can create a mesh with too rapid a transition between fine and coarse mesh regions. ) Reapply the pressure loading, repeat the solution, and replot the stress SX. 9. Main Menu > Solution > Solve > Current LS > OK Save your work. 20. File > Save as Jobname. db Plot the stresses in the X direction. 21. Main Menu > General Postproc > Plot Results > Contour Plot > Element Solu > Stress > X-Component of stress > OK Plane Stress / Plane Strain 2-13 Figure 2-20 SX stress contour after mesh refinement. Figu re 2-21 SX stress detail contour after mesh refinement. The element solution stress contours are now smooth across element boundaries, and the stress legend shows a maximum value of 4. 386 Pa, a 4. percent change in the SX stress computed using the previous mesh. To check this result, find the stress concentration factor for this problem in a text or reference book or from a suitable web site. For the geometry of this example we find Kt = 2. 17. We can compute the maximum stress using (Kt)(load)/(net cross sectional area). Using the pressure p = 1. 0 Pa we obtain. ? x MAX = 2. 17 * p * (0. 4)(0. 01) /[(0. 4 ? 0. 2) * 0. 01] = 4. 34 Pa 2-14 ANSYS Tutorial The computed maximum value is 4. 39 Pa which is around one percent in error, assuming that the value of Kt is exact. -5 THE APPROXIMATE NATURE OF FEM As mentioned above, the stiffness matrix for the truss elements of Lesson 1 can be developed directly and simply from elementary solid mechanics principles. For continuum problems in t wo and three-dimensional stress, this is generally no longer possible, and the element stiffness matrices are usually developed by assuming something specific about the characteristics of the displacements that can occur within an element. Ordinarily this is done by specifying the highest degree of the polynomial that governs the displacement distribution within an element.For h-method elements, the polynomial degree depends upon the number of nodes used to describe the element, and the interpolation functions that relate displacements within the element to the displacements at the nodes are called shape functions. In ANSYS, 2-dimensional problems can be modeled with six-node triangles, four-node quadrilaterals or eight-node quadrilaterals. Figure 2-22 Triangular and quadrilateral elements. The greater the number of nodes, the higher the order of the polynomial and the greater the accuracy in describing displacements, stresses and strains within the element. If the stress is constan t throughout a region, a very imple model is sufficient to describe the stress state, perhaps only one or two elements. If there are gradients in the stress distributions within a region, high-degree displacement polynomials and/or many elements are required to accurately analyze the situation. These comments explain the variation in the accuracy of the results as different numbers of elements were used to solve the problem in the previous tutorial and why the engineer must carefully prepare a model, start with small models, grow the models as understanding of the problem develops and carefully interpret the calculated results.The ease with which models can be prepared and solved sometimes leads to careless evaluation of the computed results. Plane Stress / Plane Strain 2-15 2-6 ANSYS FILES The files created during the solution were saved in step 20 of Tutorial 2A. Look in the working directory and you see Tutorial2A files with extensions BCS, db, dbb, esav, full, mntr, rst, and sta t. However, the Tutorial 2A problem can be reloaded using only Tutorial2A. db, so if you want to save disk space, you can delete the others. 2-7 ANSYS GEOMETRY The finite element model consists of elements and nodes and is separate from the geometry on which it may be based.It is possible to build the finite element model without consideration of any underlying geometry as was done in the truss examples of Lesson 1, but in many cases, development of the geometry is the first task. Two-dimensional geometry in ANSYS is built from keypoints, lines (straight, arcs, splines), and areas. These geometric items are assigned numbers and can be listed, numbered, manipulated, and plotted. The keypoints (2,3,4,5,6), lines (2,3,5,9,10), and area (3) for Tutorial 2A are shown below. (Your numbering may differ. ) Figure 2-23 Keypoints, lines and areas.The finite element model developed previously for this part used the area A3 for development of the node/element FEM mesh. The loads, displacement b oundary conditions and pressures were applied to the geometry lines. When the solution step was executed, the loads were transferred from the lines to the FEM model nodes. Applying boundary conditions and loads to the geometry facilitates remeshing the problem. The geometry does not change, only the number and location of nodes and elements, and at solution time, the loads are transferred to the new mesh.Geometry can be created in ANSYS interactively (as was done in the previous tutorial) or it can be created by reading a text file. For example, the geometry of Tutorial 2A can be generated with the following text file using the File > Read Input from command sequence. (The keypoint, line, etc. numbers will be different from those shown above. ) 2-16 ANSYS Tutorial /FILNAM,Geom /title, Stress Concentration Geometry ! Example of creating geometry using keypoints, lines, arcs /prep7 ! Create geometry k, 1, 0. 0, 0. 0 ! Keypoint 1 is at 0. 0, 0. 0 k, 2, 0. 1, 0. 0 , 3, 0. 5, 0. 0 k, 4, 0. 5, 0. 2 k, 5, 0. 0, 0. 2 k, 6, 0. 0, 0. 1 L, L, L, L, 2, 3, 4, 5, 3 4 5 6 ! Line from keypoints 2 to 3 ! arc from keypoint 2 to 6, center kp 1, radius 0. 1 LARC, 2, 6, 1, 0. 1 AL, 1, 2, 3, 4, 5 ! Area defined by lines 1,2,3,4,5 Geometry for FEM analysis also can be created with solid modeling CAD or other software and imported into ANSYS. The IGES (Initial Graphics Exchange Specification) neutral file is a common format used to exchange geometry between computer programs. Tutorial 2B demonstrates this option for ANSYS geometry development. -8 TUTORIAL 2B – SEATBELT COMPONENT Objective: Determine the stresses and deformation of the prototype seatbelt component shown in the figure below if it is subjected to tensile load of 1000 lbf. Figure 2-24 Seatbelt component. The seatbelt component is made of steel, has an over all length of about 2. 5 inches and is 3/32 = 0. 09375 inches thick. A solid model of the part was developed in a CAD system and exported as an IGES file. The f ile is imported into ANSYS for analysis. For simplicity we will analyze only the right, or ‘tongue’ portion of the part in this tutorial.Plane Stress / Plane Strain 2-17 Figure 2-25 Seatbelt ‘tongue’. PREPROCESSING 1. Start ANSYS, Run Interactive, set jobname, and working directory. Create the top half of the geometry above. The latch retention slot is 0. 375 x 0. 8125 inches and is located 0. 375 inch from the right edge. If you are not using an IGES file to define the geometry for this exercise, you can create the geometry directly in ANSYS with key points, lines, and arcs by selecting File > Read Input from to read in the text file given below and by skipping the IGES import steps 2, 3, 4, and 10 below. FILNAM,Seatbelt /title, Seatbelt Geometry ! Example of creating geometry using keypoints, lines, arcs /prep7 ! Create geometry k, 1, 0. 0, 0. 0 ! Keypoint 1 is at 0. 0, 0. 0 k, 2, 0. 75, 0. 0 k, 3, 1. 125, 0. 0 k, 4, 1. 5, 0. 0 k, 5, 1. 5, 0. 5 k, 6, 1. 2 5, 0. 75 k, 7, 0. 0, 0. 75 k, 8, 1. 125, 0. 375 k, 9, 1. 09375, 0. 40625 k, 10, 0. 8125, 0. 40625 k, 11, 0. 75, 0. 34375 k, 12, 1. 25, 0. 5 k, 13, 1. 09375, 0. 375 k, 14, 0. 8125, 0. 34375 2-18 L, L, L, L, L, L, L, L, ANSYS Tutorial 1, 2 3, 4 4, 5 6, 7 7, 1 3, 8 9, 10 11, 2 ! arc LARC, LARC, LARC, Line from keypoints 1 to 2 from keypoint 5 to 6, center kp 12, radius 0. 25, etc. 5,6, 12, 0. 25 8, 9, 13, 0. 03125 10, 11, 14, 0. 0625 AL,all ! Use all lines to create the area. 2. Alternatively, use a solid modeler to create the top half of the component shown above in the X-Y plane and export an IGES file of the part. To import the IGES file 3. Utility Menu > File > Import > IGES Select the IGES file you created earlier. Accept the ANSYS import default settings. If you have trouble with the import, select the alternate options and try again.Defeaturing is an automatic process to remove inconsistencies that may exist in the IGES file, for example lines that, because of the modeling or th e file translation process, do not quite join to digital precision accuracy. Figure 2-26 IGES import. Turn the IGES solid model around if necessary so you can easily select the X-Y plane. Plane Stress / Plane Strain 2-19 4. Utility Menu > PlotCtrls > Pan, Zoom, Rotate > Back, or use the side-bar icon. Figure 2-27 Seatbelt solid, front and back. 5.Main Menu > Preprocessor > Element Type > Add/Edit/Delete > Add > Solid > Quad 8node 183 > OK (Use the 8-node quadrilateral element for this problem. ) 6. Options > Plane strs w/thk > OK > Close Enter the thickness 7. Main Menu > Preprocessor > Real Constants > Add/Edit/Delete > Add > (Type 1 Plane 183) > OK > Enter 0. 09375 > OK > Close Enter the material properties 8. Main Menu > Preprocessor > Material Props > Material Models Material Model Number 1, click Structural > Linear > Elastic > Isotropic Enter EX = 3. 0E7 and PRXY = 0. > OK (Close Define Material Model Behavior window. ) Now mesh the X-Y plane area. (Turn on area numbers if it helps. ) 9. Main Menu > Preprocessor > Meshing > Mesh > Areas > Free. Pick the X-Y planar area > OK IMPORTANT NOTE: The mesh below was developed from an IGES geometry file. Using the text file geometry definition, may produce a much different mesh. If so, use the Modify Mesh refinement tools to obtain a mesh density that produces results with accuracies comparable to those given below. Computed stress values can be surprisingly sensitive to mesh differences. -20 ANSYS Tutorial Figure 2-28 Quad 8 mesh. The IGES solid model is no longer needed, and since its lines and areas may interfere with subsequent modeling operations, we can delete it from the session. 10. Main Menu > Preprocessor > Modeling > Delete > Volume and Below (Don’t be surprised if everything disappears. Just Plot > Elements to see the mesh again. ) 11. Utility Menu > PlotCtrls > Pan, Zoom, Rotate > Front front side of mesh. ) (If necessary to see the Figure 2-29 . Mesh, front view. Now apply displacement and pr essure boundary conditions.Zero displacement UX along left edge and zero UY along bottom edge. 12. Main Menu > Preprocessor > Loads > Define Loads > Apply > Structural > Displacement > On Lines Pick the left edge > UX = 0. > OK 13. Main Menu > Preprocessor > Loads > Define Loads > Apply > Structural > Displacement > On Lines Pick the lower edge > UY = 0. > OK The 1000 lbf load corresponds to a uniform pressure of about 14,000 psi along the ? inch vertical inside edge of the latch retention slot. [1000 lbf/(0. 09375 in. x 0. 75 in. )]. 14.Main Menu > Preprocessor > Loads > Define Loads > Apply > Structural > Pressure > On Lines Plane Stress / Plane Strain 2-21 Select the inside line and set pressure = 14000 > OK Figure 2-30 Applied displacement and pressure conditions. Solve the equations. SOLUTION 15. Main Menu > Solution > Solve > Current LS > OK POSTPROCESSING Comparing the von Mises stress with the material yield stress is an accepted way of evaluating static load yielding for du ctile metals in a combined stress state, so we enter the postprocessor and plot the element solution of von Mises stress, SEQV. 16.Main Menu > General Postproc > Plot Results > Contour Plot > Element Solu > Stress > (scroll down) von Mises > OK Zoom in on the small fillet where the maximum stresses occur. The element solution stress contours are reasonably smooth, and the maximum von Mises stress is around 118,000 psi. Further mesh refinement gives a stress value of approximately 140,000 psi. The small fillet radius of this geometry illustrates the challenges that can arise in creating accurate solutions, however you can easily come within a few percent of the most likely true result using the methods discussed thus far.Figure 2-31 Von Mises stresses. 2-22 ANSYS Tutorial Redesign to reduce the maximum stress requires an increase in the thickness or fillet radius. Look at charts of stress concentration factors, and you notice that the maximum stress increases as the radius of the str ess raiser decreases, approaching infinite values at zero radii. If your model has a zero radius notch, your finite-size elements will show a very high stress but not infinite stress. If you refine the mesh, the stress will increase but not reach infinity.The finite element technique necessarily describes finite quantities and cannot directly treat an infinite stress at a singular point, so don’t ‘chase a singularity’. If you do not care what happens at the notch (static load, ductile material, etc. ) do not worry about this location but examine the stresses and strains in other regions. If you really are concerned about the maximum stress in a particular location (fatigue loads or brittle material), then use the actual part notch radius however small (1/32 for this tutorial); do not use a zero radius.Also examine the stress gradient in the vicinity of the notch to make sure the mesh is sufficiently refined near the notch. If a crack tip is the object of the anal ysis, you should look at fracture mechanics approaches to the problem. (See ANSYS help topics on fracture mechanics. ) The engineer’s responsibility is not only to build useful models, but also to interpret the results of such models in intelligent and meaningful ways. This can often get overlooked in the rush to get answers. Continue with the evaluation and check the strains and deflections for this model as well. 7. Main Menu > General Postproc > Plot Results > Contour Plot > Element Solu > Strain-total > 1st prin > OK The maximum principal normal strain value is found to be approximately 0. 004 in/in. 18. Main Menu > General Postproc > Plot Results > Contour Plot > Nodal Solu > DOF Solution > X-Component of displacement > OK Figure 2-32 UX displacements. Plane Stress / Plane Strain 2-23 The maximum deflection in the X direction is about 0. 00145 inches and occurs as expected at the center of the right-hand edge of the latch retention slot. -9 MAPPED MESHING Quadrilateral m eshes can also be created by mapping a square with a regular array of cells onto a general quadrilateral or triangular region. To illustrate this, delete the last line, AL,all, from the text file above so that the area is not created (just the lines) and read it into ANSYS. Use PlotCtrls to turn Keypoint Numbering On. Then use 1. Main Menu > Preprocessor > Modeling > Create > Lines > Lines > Straight Line. Successively pick pairs of keypoints until the four interior lines shown below are created. Figure 2-33 Lines added to geometry. 2.Main Menu > Preprocessor > Modeling > Create > Areas > Arbitrary > By Lines Pick the three lines defining the lower left triangular area. > Apply > Repeat for the quadrilateral areas. > Apply > OK Figure 2-34 Quadrilateral/Triangular regions. 3. Main Menu > Preprocessor > Modeling > Operate > Booleans > Glue > Areas > Pick All 2-24 ANSYS Tutorial The glue operation preserves the boundaries between areas that we will need for mapped meshing. 4. Main Men u > Preprocessor > Meshing > Size Cntrls > ManualSize > Lines > All Lines Enter 4 for NDIV, No. lement divisions > OK All lines will be divided into four segments for mesh creation. Figure 2-35 Element size on picked lines. 5. Main Menu > Preprocessor > Element Type > Add/Edit/Delete > Add > Solid > Quad 8node 183 > OK (Use the 8-node quadrilateral element for the mesh. ) 6. Main Menu > Preprocessor > Meshing > Mesh > Areas > Mapped > 3 or 4 sided > Pick All The mesh below is created. Applying boundary and load conditions and solving gives the von Mises stress distribution shown.The stress contours are discontinuous because of the poor mesh quality. Notice the long and narrow quads near the point of maximum stress. We need more elements and they need to be better shaped with smaller aspect ratios to obtain satisfactory results. Plane Stress / Plane Strain 2-25 Figure 2-36 Mapped mesh and von Mises results. One can tailor the mapped mesh by specifying how many elements are to be plac ed along which lines. This allows much better control over the quality of the mesh, and an example of using this approach is described in Lesson 4. 2-10 CONVERGENCEThe goal of finite element analysis as discussed in this lesson is to arrive at computed estimates of deflection, strain and stress that converge to definite values as the number of elements in the mesh increases, just as a convergent series arrives at a definite value once enough terms are summed. For elements based on assumed displacement functions that produce continuum models, the computed displacements are smaller in theory than the true displacements because the assumed displacement functions place an artificial constraint on the deformations that can occur.These constraints are relaxed as the element polynomial is increased or as more elements are used. Thus your computed displacements usually converge smoothly from below to fixed values. Strains are the x and/or y derivatives of the displacements and thus depend o n the distribution of the displacements for any given mesh. The strains and stresses may change in an erratic way as the mesh is refined, first smaller than the final computed values, then larger, etc. Not all elements are developed using the ideas discussed above, and some will give displacements that converge from above. (See Lesson 6. In any case you should be alert to computed displacement and stress variations as you perform mesh refinement during the solution of a problem. 2-11 TWO-DIMENSIONAL ELEMENT OPTIONS The analysis options for two-dimensional elements are: Plane Stress, Axisymmetric, Plane Strain, Plane Stress with Thickness and Generalized Plane Strain. The two examples thus far in this lesson were of the third type, namely problems of plane stress in which we provided the thickness of the part. 2-26 ANSYS Tutorial The first analysis option, Plane Stress, is the ANSYS default and provides an analysis for a part with unit thickness.If you are working on a design problem in which the thickness is not yet known, you may wish to use this option and then select the thickness based upon the stress, strain, and deflection distributions found for a unit thickness. The second option, Axisymmetric analysis is covered in detail in Lesson 3. Plane Strain occurs in a problem such as a cylindrical roller bearing caged against axial motion and uniformly loaded in a direction normal to the cylindrical surface. Because there is no axial motion, there is no axial strain.Each slice through the cylinder behaves like every other and the problem can be conveniently analyzed with a planar model. Another plane strain example is that of a long retaining wall, restrained at each end and loaded uniformly by soil pressure on one or both faces. The Generalized Plane Strain feature assumes a finite deformation domain length in the Z direction, as opposed to the infinite value assumed for standard plane strain. 2-12 SUMMARY Problems of stress concentration in plates subject to in-plane loadings were used to illustrate ANSYS analysis of plane stress problems.Free triangular and quadrilateral element meshes were developed and analyzed. Mapped meshing with quads was also presented. Similar methods are used for solving problems involving plane strain; one only has to choose the appropriate option during element selection. The approach is also applicable to axisymmetric geometries as discussed in the next lesson. 2-13 PROBLEMS In the problems below, use triangular and/or quadrilateral elements as desired. Triangles may produce more regular shaped element meshes with free meshing.The six-node triangles and eight-node quads can approximate curved surface geometries and, when stress gradients are present, give much better results than the four-node quad elements. 2-1 Find the maximum stress in the aluminum plate shown below. Use tabulated stress concentration factors to independently calculate the maximum stress. Compare the two results by determining the percen t difference in the two answers. Convert the 12 kN concentrated force into an equivalent pressure applied to the edge. Plane Stress / Plane Strain 2-27 Figure P2-1 -2 Find the maximum stress for the plate from 2-1 if the hole is located halfway between the centerline and top edge as shown. You will now need to model half of the plate instead of just one quarter and properly restrain vertical rigid body motion. One way to do this is to fix one keypoint along the centerline from UY displacement. Figure P2-2 2-28 ANSYS Tutorial 2-3 An aluminum square 10 inches on a side has a 5-inch diameter hole at the center. The object is in a state of plane strain with an internal pressure of 1500 psi. Determine the magnitude and location of the maximum principal stress, the maximum rincipal strain, and the maximum von Mises stress. Note that no thickness need be supplied for plane strain analysis. Figure P2-3 2-4 Repeat 2-3 for a steel plate one inch thick in a state of plane stress. 2-5 See if yo u can reduce the maximum stress for the plate of problem 2-1 by adding holes as shown below. Select a hole size and location that you think will smooth out the ‘stress flow’ caused by the load transmission through the plate. Figure P2-5 2-6 Repeat 2-1 but the object is now a plate with notches or with a step in the geometry. (See the next figure. ) Select your own dimensions, materials, and loads.Use published stress concentration factor data to compare to your results. The published results are for plates that are relatively long so that there is a uniform state of axial stress at either end relatively far from notch or hole. Create your geometry accordingly. Plane Stress / Plane Strain 2-29 Figure P2-6 2-7 Solve the seatbelt component problem of Tutorial 2B again using six node triangular elements instead of the quadrilaterals. Experiment with mesh refinement. Turn on Smart Sizing using size controls to examine the effect on the solution. See if you can compute a maxi mum von Mises stress of around 140 kpsi. -8 Determine the stresses and deflections in an object ‘at hand’ (such as a seatbelt tongue or retaining wall) whose geometry and loading make it suitable for plane stress or plane strain analysis. Do all the necessary modeling of geometry (use a CAD system if you wish), materials and loadings. 2-9 A cantilever beam with a unit width rectangular cross section is loaded with a uniform pressure along its upper surface. Model the beam as a problem in plane stress. Compute the end deflection and the maximum stress at the cantilever support. Compare your results to those you would find using elementary beam theory.Figure P2-8 Restrain UX along the cantilever support line, but restrain UY at only one keypoint along this line. Otherwise, the strain in the Y direction due to the Poisson effect is prevented here, and the root stresses are different from elementary beam theory because of the singularity created. (Try fixing all node points in UX and UY and see what happens. ) Select your own dimensions, materials, and pressure. Try a beam that’s long and slender and one that’s short and thick. The effect of shear loading becomes more important in the deflection analysis as the slenderness decreases.

How Great Companies Think Differently - 900 Words

Strategic Management How Great Companies Think Differently Making money has long been the ultimate aim of a business. This capitalism vision has influenced the majority of corporations limit their goals in generating the highest profits and returns to owners, regardless the health and safety of employees, the environment, and general public. An institutional logic, therefore, has been raised by professor of Harvard Business Schoolï ¼ Kanter. Unlike traditional practices, this logic addressed a successful company is a vehicle for enhancing societal welfares, rather than only a machine to make money. Not only can most well-established companies distribute sound returns to shareholders, but also build long-lasting institutions. In†¦show more content†¦It is aimed at providing professional business education and to equip personnel with capability, solicitude, conscientiousness and creativity. It aligns the goals of Hang Seng Bank in pursuit of excellence for the customers and common good for Hong Kong society. It is wise for a business to focus on long term sustainable development by performing ethical roles to society. When Hang Seng Bank educates and nurtures the next generations, it can also benefits from recruitment of quality employees from Hang Sang School of Commerce. This secures the future development of Hang Seng Bank, which would keep going with its ultimate goals. The morale of the employees, indeed, is a key determined factor for a successful corporate. In Hang Sang School of Commerce, it is obvious that all teachers want to educate the best students—to get the more As, so that they can also be rewarded from promotion and bonus. Associated with social enterprise is also critical to build an enduring institution. Through demonstrating the companys commitment to furthering the development of the countries, the company can get supports from public and know more about the preferences of the residents. Standard Chartered Bank (Hong Kong), holds marathon races every year, demonstrating the core value of Hong Kong—diligence. Honestly, Standard Chartered has customized services with high efficiency and effectiveness. It has won numerous awards in Hong Kong and Asia, such as bestShow MoreRelatedThe Importance Of Team Sports1222 Words   |  5 Pagescareer, I’ve learned many valuable life lessons as well as picked up many skills. Sports are a great way to get outside and enjoy the world around us while learning some valuable skills. Team sports can benefit us in many ways by helping to shape our personality while learning good sportsmanship, which can transfer into other aspects of our life. 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The Presence Of Parent And Child Communication - 1259 Words

The presence of parent and child communication also matters. It is important for parents to discuss sex, love, and relationships directly with their children. Parents who thoroughly communicate their values and expectations to their children, express their concerns and love at an early age and do it often, and gives sufficient supervision — including their child’s selection of friends and role models — raise children who are more likely to avoid early sexual activity, pregnancy, and parenthood than those parents who do not. (Kim, (2008). This can be harder when there is only one parent. The probability of this communication becomes less and it results in such behavior. Much of the time that parent is working full-time and trying to maintain the home, in addition to everything that comes with parenting a child. Outside factors can lead to less communication especially from a single parent raising a teen alone. 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Do Violent Video Games Affect Real World Aggression And...

Do violent video games influence real world aggression and violence, among other harmful behaviors, within children and young teens? Yes, they do, without a doubt. Children and teens that extensively play violent games tend to be less stressed, but are also more prone to stealing, over-eating, and acting out in minor rages when playing violent video games for long extensions of time. Though most of the side effects do not damage a young child or teen physically, the effects can result in social problems such as having outbursts in school or being dishonest or disrespectful to others. Some, of course, say that violent games do not play a part in real world violence. That statement is wrong, because these days, in this generation, the youth imitate what they see in the media, read on a wiki page, or what they play in a game. There are a few things that can be done about this such as disabling the youth to play or watch such media until a certain age or perhaps even limiting the amount of violence played or watched would greatly help the issue. With that said, much of the youth are drawn to games such as Call of Duty, God of War, and Battlefield. The patterns with all three of those games is simple: they are based off of major violence. There is no question about it, violent video games do, in fact, influence youthful violence. The evidence to support this claim is everywhere from media to literature. Take the peer-reviewed article titled â€Å"The Effects of Profanity in ViolentShow MoreRelated Video Games Violence Essay1580 Words   |  7 Pagesplayed video games once in their lives. There are various genres and types of video games such as action, first person shooters, adventure, education, role-playing, strategy, and many more. 89% of video games contain some violent content (Slife, 2008). 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Many People Have Different Learning Styles Free Essays

Your role of organizing and delivering training tarts by identifying the learners’ needs. Before the course starts, You need to carry out an initial assessment of all learners, by direct contact or through their training manager / unit manager. Planning Your responsibilities are: 1 . We will write a custom essay sample on Many People Have Different Learning Styles or any similar topic only for you Order Now To ensure that once the syllabus is known, you prepare for the lesson and lesson plans generated 2. To ensure the course structure and timetable are developed 3. To ensure that resources are planned IEEE laptops, projectors etc 4. To ensure accommodation is suitable 5. To get to know our students and their needs 6. To ensure that our knowledge is up to date 7. Organization is number 1 priority in delivering a good lesson 8. To organize the class room layout to suit the group you are teaching. It is necessary to keep up to date with any changes in the training curriculum, especially in SST John Ambulance as things like first aid modifications / principals change frequently to keep up with modern changes in everyday lifestyle and delivering first aid or methods in teaching. Shoots Ambulance offer regular training days / evenings to keep up to date with any changes. Boundaries with Planning There are limitations with planning, in that a Teacher can only plan for what s known and there may be unexpected occurrences that have to be dealt with in the lesson. However, there also has to be an element of â€Å"expect the unexpected† Delivery Your responsibilities are 1. To ensure that delivery is clear and concise 2. That standards are maintained 3. That YOU deliver your lesson to a consistently high standard 4. That YOU deliver a differentiated lesson taking into account different learning styles, and a differentiated lesson to engage learners at different levels. How to cite Many People Have Different Learning Styles, Essays

Consumer Promotion free essay sample

I expect this report to fulfill the requirements of my internship program (BBA 449) at Unilever Bangladesh Limited. I have put in my best efforts to make this report a success. However, I am sure that this report could have been a more superior one, if it had not been my first time to conduct such a relational study. However this has obviously been a great source of learning for me to conduct similar research studies in future. I would like to express my sincere gratitude to you for your guidance and suggestions in preparing the report. I will be happy to provide any further explanation regarding this research report if necessary. Thanking You. Sincerely yours, Muhammad Mashfiq Huq ID# 0131001 Acknowledgements In preparing this report a considerable amount of thinking and informational inputs from various sources were involved. I express my sincere gratitude to everyone who contributed towards making this research report possible. Major contributions were received from officials at Unilever Bangladesh Limited and Independent University, Bangladesh. First of all I would like to thank the authorities of Unilever Bangladesh Limited to give me the prized opportunity to do my internship at their prestigious organization. The experience and knowledge gained at Unilever Bangladesh Limited helped me immensely to address and understand all the elements related to my report, which I otherwise would not have understood so well. I would like to specially thank my supervisor at Unilever Bangladesh Limited, Mr Rajeeb Bhattacharjee, Product Group Manager for Wheel, for his absolute support, co-operation and encouragement that he extended to me from the very first day. In spite of having a very busy schedule, he made sure in every way that I acquire the best possible exposure and knowledge during my tenure as an intern under him. My sincere gratitude goes to my internship supervisor Mr. Muzahid Akbar, for encouraging me at the very first place, to undertake such a relational study to fulfill my internship requirements. He gave all the time and attention, which I needed to complete my research and compile my report in as much orderly way as possible. Last but not the least I would like to thank the respondents of my survey, for sparing the time to fill out the questionnaires. This research would not have been possible without their valuable inputs. Table of Contents Page Executive Summary 1. 0 Introduction 1. Statement of the Problem 1. 2 Purpose of the Study 1. 3 Research Timeline 1. 4 Limitations 2. 0 Review of Literature 2. 1 Consumer Promotion 2. 2 Price Perceptions 2. 3 Product Quality Perceptions 2. 4 Brand Loyalty 2. 5 Relation between consumer promotion and product quality perception 2. 6 Relationship between price perception and product quality perceptions 2. 7 Relationship between consumer promotion and brand loyalty 2. 8 Relationship between price perception and brand loyalty 2. 9 Relationship between quality perception and brand loyalty 3. 0 Research Questions 4. 0 Hypothesis 5. Development of Conceptual Framework I 1 2 2 2 2 3 3 4 4 5 6 6 7 7 8 9 9 10 6. 0 Methodology 6. 1 Research design 6. 2 Sampling method 6. 3 Survey instrument 6. 4 Data Collection 6. 5 Data Analysis 7. 0 Results 7. 1 Reliability coefficients and descriptive statistics 7. 2 Correlation analysis 7. 3 Regression analysis 7. 3. 1 Regression analysis for Model 1 7. 3. 2 Regression analysis for Model 2 8. 0 Assessment of Research Hypothesis 9. 0 Recommendation 10. 0 Conslusion References Appendices 11 11 11 12 13 13 13 13 15 16 16 17 18 22 24 25 29 List of Tables Page 1. Reliability coefficients and descriptive statistics 2. Correlation matrix of the study variables 3. Stepwise regression on Product Quality Perceptions 4. Stepwise regression on Brand Loyalty 13 15 16 17 Executive Summary This paper is directed towards exploring the relationship between consumer promotion, price perception, product quality perceptions and brand loyalty in the detergent market of Bangladesh. Through sizeable literature review and discussions it is known that there is considerable correlation that exists among the study variables mentioned above. The data sampling was conducted on the customers of different brands of detergents. A structured questionnaire was used to find out the views of people regarding consumer promotion in detergent brands, price perceptions about the promoted brands of detergent, product quality perceptions about those brands and also to find out about brand loyalty in the detergent markets. A correlation analysis and a stepwise regression analysis were run on the collected data to analytically explore the relations and their extent. It was found that consumer promotion is positively correlated with the product quality perceptions and brand loyalty of those brands. Meaning that if a person views the consumer promotion positively, then his/ her perception of the product quality about a promoting brand will be proportionately high. It also means that the chances of the same person being brand loyal towards that brand would also be high. There is a positive correlation of price perception with perceived quality and brand loyalty. According to this, if the perceived prices of the promoted brands are fair then it would have positive effects on product quality perception and brand loyalty of that brand. It has also been found that product quality perceptions about promoted brands are positively correlated with brand loyalty of those brands. Overall consumer promotions are expected to give positive results with the people who have positive views about consumer promotion and who can be influenced by promotional efforts. So while deciding about consumer promotion it should be thought in advance that who is the consumer promotion activity aimed at. This way wastage of large amounts of money can be avoided by spending on ineffective consumer promotion activity. Every effort should be given to make the consumers think that the prices of the promoted brand are fair, even when there is no promotional activity is undertaken. Though there is a tendency in the detergent market to provide frequent promotional offers, yet the perceived quality should in no way go down because there is a good possibility that the brand loyalty would also go down. Introduction Bangladesh has a detergent market of about 8. 8 billion taka of which Unilever occupies a share of 30% making it the market leader. The major competitor brands in the detergent market for Unilever are Keya, Chaka and Tibet. To fight this steep competition the above mentioned companies constantly run consumer promotion in hope to sell more than the respective competitors. Although this strategy worked well at first but with the passage of time, the intense consumer promotions have done little to prevent Unilever from loosing shares to its competitors. In 2004, Wheel, Unilever’s largest detergent brand ran about nine consumer promotions where as in 2005 it ran no consumer promotions at all. Consumer promotion over all is a very expensive affair. Unilever has the largest brands of detergent and so the cost of providing a consumer promotion offer is also large by the same proportion. Besides the competitor brands are known to involve in some unfair practices. They pay a very low wage rate to their labours so overhead costs are low, they under invoice their imported raw materials so that they can evade import taxes and other duties, so they save a lot of money in the process. They can then utilize this money for consumer promotion and other competitive activities that can earn them a higher share of the market. Therefore it is imperative that consumer promotions and other dependant elements have to be studied, to make sure that if a consumer promotion activity is implemented it is a highly effective one. This way, precious monetary resources have the minimum chances of being wasted. To understand the competition in the detergent market better price perceptions and product quality perceptions about the brands of detergent on promotion are also considered being worth studying. To look at market share issues, the brand loyalty element should also be explored. Statement of the Problem There are many companies that are operating to serve the detergent markets; as a result the competition has heightened. Consumer promotions are being heavily used in the detergent markets to increase sales of each available brand. Consumer promotions, when implemented use up a lot monetary resources. Failure to implement the consumer promotion activity effectively may result in major loss of money. Purpose of the Study The purpose of this research is to explore the relationship between consumer promotions, price perceptions with product quality perceptions and brand loyalty in the detergent market of Bangladesh. Research Timeline 2005 2005 2005 2005 2005 October November November 20 November 28 December 6 Research proposal writing and literature rivew Data collection (surveys etc. ) Data analysis and interpretation Draft submission of research report Submission of research report Limitations There are vast amounts of information and write-ups relating to the topics of this research that are present in the internet and various other sources, but it was not possible to gain access to many such information. So missing out some important aspect of the discussed topics can be a possibility. There is a major time constraint in doing the research work and preparing the report, a much larger pool of information could have been dealt with if there was more time to analyze them. A minimal sample size will be used for this research; if a larger sample was taken into consideration the research would have been more accurate. The survey will be conducted in Dhaka city which could be a possible reason for the people’s mind set to be similar and survey results not being very different from each other, the results could be different if people from outside metropolitan cities were brought under consideration. Review of Literature Consumer Promotion Sales promotions as we know is a very important component of marketing promotion. Consumer promotion (e. g. coupons, samples, contests, sweepstakes, and price packs) is a part of sales promotion that is targeted towards the final buyers of consumer products (Kotler and Armstrong, 2002). There can be various types of consumer sales promotion some are incentive based while others are communicative in nature (Kotler et al. , 1999; Tellis, 1998). The incentive based promotions can be price oriented promotion or non price-oriented promotion. According to Britannica (article 21279) advertising presents a reason to buy a product but consumer promotion offers a short-term incentive to purchase. Consumer promotions often attract brand switchers (those who are not loyal to a specific brand) who are looking primarily for low price and good value. Thus, especially in markets where products are highly similar, consumer promotions can cause a short-term increase in sales. Abraham and Lodish (1987) stated that many consumer goods categories sold 90% of their volume on special deals which is a result of consumer promotion. Consumer promotion is thought to be a tool that helps manufacturers and retailers to achieve their objectives of generating sales (Alvarez and Casielles, 2004). They also stated that the influence of sales promotions on the consumer will also depend on the consumer’s characteristics Price Perceptions According to Schiffman and Kanuk (2004) price perception is about how customers see a product’s price, as high, low or fair. They also stated that perception of price unfairness affect consumers’ perceptions of value and ultimately their willingness to buy a product. According to Moore et al. (2003) years of research concerned with price show both positive and negative perceptions serve as marketplace cues. Several studies have also portrayed the role of price perceptions as an attribute to success (Jiang and Rosenbloom, 2004). When the price perceptions are high this is a sign of positive quality, prestige and status (Moore et al. , 2003). The concept of reference price is related to price perceptions. Schiffman and Kanuk (2004) stated that reference price is the price the consumers use as a basis for comparison in judging another price. It is through reference price that the price perception of a brand of product is formed. When the consumer plans to buy a product, he or she will judge prices comparatively with the reference prices in order to determine whether the price is acceptable or not (Alvarez and Casielles, 2004). They also stated that, a result of consumers’ comparison between the prices and the reference price, potential losses and gains emerge. The consumer perceives a gain when the reference price is higher than the observed price. If the observed price is higher than the reference price, the consumer experiences a loss. Product Quality Perceptions Product quality perceptions represent consumer judgment about the superiority of a product, which the user-based approaches think is essential in describing quality (Forker et al. , 1996). Bundles of attributes together represent a certain level of quality, which therefore provide utility to the customer (Snoj et al. , 2004). The benefits are measured through a perceived level of quality (level of working superiority), a bundle of attributes in comparison with the consumer’s expectations. Schiffman and Kanuk (2004) stated consumers often judge the quality of a product on the basis of a variety of informational cues that they associate with the product. They also stated that the cues can either be intrinsic or extrinsic. Intrinsic cues are related to the physical characteristics of the product itself, like size, colour, flavour, aroma etc. The extrinsic cues on the other hand are related to elements that are put together with the actual product like packaging, pricing, advertising etc. The perceived quality of products and services is central to the theory that strong brands add value to consumers purchase evaluations (Low and Lamb, 2000). Brand Loyalty Brand loyalty is the ultimate desired outcome of consumer learning (Schiffman and Kanuk, 2004). According to Rawly and Dawes (1999) brand loyalty is the likelihood of positive attitudes and behaviours of consumers towards a particular brand, this could amount to repeat purchase and positive word of mouth. They also stated that a loyal customer base is an asset for a company and it reduces the need for seeking new customers. It is also a known fact that retaining current customers requires less money and effort than getting new ones. The strongest measure of brand value is the loyalty a company produces among customers (Aaker, 1996). According to Quester and Lim (2003) brand loyalty is known to have two components, namely attitudinal loyalty and behavioural loyalty. Behavioural loyalty is related to consistent purchase behaviour of a specific brand; it is the consumer’s overt purchase behaviour (Dikempe et al. , 1997) while attitudinal loyalty refers to a highly favourable attitude towards a particular brand. Rowley and Dawes (1999) stated that to understand brand loyalty better the following components of attitude model should be considered: 1. Cognitive component – associated with a â€Å"rational decision making based on informational determinants. 2. Affective component associated with emotions and feelings about the product or service. 3. Conative components – associated with a behavioral disposition. Relation between consumer promotion and product quality perceptions A primary reason for consumer promotion is to give an impression of greater quality and appeal to the potential customers (Alvarez and Casielles, 2004). Sales promotion influence the relative weighting of the utility factors and extends the perceived quality (Groth and Dye, 1999). Sales promotions can offer many benefits, the most obvious being monetary savings, and also motivation to perceive higher quality, convenience, value (Quock and Uncles, 2005). The way a consumer promotion is framed is likely to effect consumers perceptions of price, quality, value, and purchase intentions (Munger and Grewal, 2001). Ong (1997) on the other hand stated that there is a danger of unfavorable consumer perception as a result of consumer promotion activity like bonus packs etc. Consumers tend to think that at the normal price or offering they over pay for a given level of quality, so their quality perception is affected. Relationship between price perception and product quality perceptions The more quality a product possesses the more utility it contains and the more its price should be in the market (Sjolander, 1992). According to Sjolander (1992) it is very much expected that there is a very strong positive relation between perceived price and perceived quality. Perceived quality explains a considerable portion of the variance in the price the consumers are willing to pay for different brands (Low and Lamb, 2000). Unfavorable price perceptions may have a direct effect on customer intention to switch to a different brand, because the consumers might think that the price does not match quality (Jiang and Rosenbloom, 2004). Companies sometimes attempt to appeal to uninformed consumers by using high prices from start as a signal of high quality, with the belief that if they perceive the price of their products to be high then they automatically perceive the product quality to be high as well (Kalita et al. , 2004). Relationship between consumer promotion and brand loyalty According to Alvarez and Casielles (2004) promotions can have, as an effect, the consumer acquiring a brand that he or she would not otherwise try. They also stated that categories of products whose buyers are very loyal, consumer promotion activity like coupons etc that reward the loyalty could have a bigger effect. Srinivasan and Anderson (1998) acknowledged that many times sales promotions are used by new entrants to break consumers’ brand loyalty toward established brands. In the short run, established brands may be able to ignore sales promotions from new brands without serious loss of sales. Over the longer run, however, unless proper defensive and counter-offensive strategies are developed and implemented, established brands can gradually lose their loyal customer base. Dawes (2004) on the other hand stated that repeat buying rates that buying a brand on promotion decreases the likelihood of a subsequent purchase of that brand. Relationship between price perception and brand loyalty Alvarez and Casielles (2004) stated that when the consumer perceives a loss, the utility that the provides (brand) will diminish, and with it the likelihood of purchase will also go down. If, in contrast, the consumer perceives a gain, he or she will be more inclined to purchase the brand. Price perceptions are expected play an increased role in determining both post-purchase satisfaction and brand loyalty (Jiang and Rosenbloom, 2004). According to representative research higher perceived prices leads to expectation of higher perceived quality and value, in turn lead to higher levels of satisfaction of customers, greater levels of customer loyalty and retention and to a greater success of organizations (Snoj et al. , 2004). Relationship between quality perception and brand loyalty According to Ruyter and Wetzels (1997) the perceived quality is often viewed as a pre-requisite for loyalty and that perceived quality contributes positively to increase loyalty. They also stated that the influence of quality on preference loyalty generally varies per industry. Boulding et al. (1993) found positive relationships between quality and repurchase intentions and willingness to recommend to others. Because product quality perceptions influence value, efforts of marketers have focused on improving product quality in order to enhance perceptions of value, and consequently purchase intentions leading to loyalty (Grewal and Munger, 2001). The loyal customers, who gave indication that they would return, will be the internal level for managers to improve their quality in order to increase customer loyalty (Bowen and Chen, 2001). Research Question The following questions have to be addressed for the study: 1. Is there any significant relationship between consumer promotion and product quality perception in the detergent market of Bangladesh? 2. Is there any significant relationship between price perception and product quality perception in the detergent market of Bangladesh? 3. Is there any significant relationship between consumer promotion and brand loyalty in the detergent market of Bangladesh? 4. Is there any significant relationship between price perception and brand loyalty in the detergent market of Bangladesh? 5. Is there any significant relationship between product quality perception and brand loyalty in the detergent market of Bangladesh? Hypothesis The hypothesis that can be derived from the research questions are: 1. There is significant relationship between consumer promotion and product quality perception in the detergent market of Bangladesh. 2. There is significant relationship between price perception and product quality perception in the detergent market of Bangladesh. 3. There is significant relationship between consumer promotion and brand loyalty in the detergent market of Bangladesh. . There is significant relationship between price perception and brand loyalty in the detergent market of Bangladesh. 5. There is significant relationship between product quality perception and brand loyalty in the detergent market of Bangladesh. Development of Conceptual Framework †¢ Consumer Promotion †¢ Price Perception †¢ Product Quality Perception Figure 1 . Model 1: Conceptual F ramework of research variables †¢ Consumer Promotion †¢ Price Perception †¢ Product Quality Perception †¢ Brand Loyalty Figure 2. Model 2: Conceptual Framework of research variables Methodology Research design The illustrations of the conceptual framework model 1 and 2 (Figure 1 and 2) above gives a visual idea of the relationship and structure that exists among the study variables. The main purpose of the research is to assess the existing correlation among the variables. This research is about exploring and understanding the relationship that exists between consumer promotion, price perception with product quality perceptions and brand loyalty in the detergent market of Bangladesh. Here in the first model (figure 1) the independent variables are assigned to be consumer promotions and price perceptions. The dependant variable on the other hand is product quality perception. In the second model (figure 2) the independent variables are consumer promotions, price perceptions and product quality perceptions, in this case the dependant variable is brand loyalty. So the researcher is attempting to find out, if any changes in the independent variable have a changing effect on the dependant ones as well, thereby proving that a relationship exists. The researcher also tried to find out the degree to which a change in the dependant variables has an impact on the independent ones, in other words the degree of relation is also explored here. Therefore the correlation study was chosen for this research. Sampling method The required data for this research was collected from the regular customers of detergents. There was no particular sample frame available for this research so convenience sampling was used, as it is also the cheapest and the easiest methods of sampling. The sample frame for this research consisted of shoppers (mainly house wives) at different shopping centres and stores etc, and also the parents of school children were included. In the shopping centres the researcher surveyed the people who seemed to be the most appropriate respondent for this kind of survey. The parents of kindergarten students, who spend time waiting for their kids outside the schools, were also surveyed, because they usually have a lot of time to spare and can give valuable inputs. Due to time constraints the survey was conducted in Dhaka city only. Over all there were about a 104 people who participated in the survey. Survey instrument A structured questionnaire was used to collect data. The questionnaire consists of different parts to gather information on the different variables under considerations. The questionnaire is the best instrument for the survey in this case because, for a correlation study the sample sizes have to be very large as it is quantitative in nature, so surveying so many people with personal interviews or observations would be next to impossible. With questionnaires, no responses of the respondents can be missed out. It gives more time to the respondents to think and then give the answers. And it is a quicker and cheaper way to conduct the survey. Questionnaires can be conducted in any environment, with minimum influence of the outside environment. Questionnaires also have the advantage of keeping the personal details of the respondents confidential. A sample of the questionnaire has been attached in the appendix 1. The first 6 questions have been set to measure the respondents’ opinions regarding sales promotion.