FATIGUE ANALYSIS OF ALLOY WHEEL UNDER DIFFERENT PRESSER AND DIFFERENT Raman Mehra Research Scholar, Department of Mechanical Engineering, OITM, Juglan, Hisar- 125001, Haryana, India raman.mehra9@gmail.com Abstract--This Research will present and discuss the use of finite element technique for simulation test of functionality of automotive allow wheel nature during operation. A specific design wheel is used. The load for stress distribution and displacement data subjected to loading on alloy wheel is viable trough the finite element model. The result and how wheel performed is discussed. In the literature, finite element analysis has been used widely used to investigate the stress distribution and fatigue analysis in the wheel. However, the parameters affecting the load is not well defined. The effects of s on the entire wheel needs to be studied. ln this work the effects of the aforementioned variables on the wheel is systematically analyzed. In this thesis, study was carried out on an Aluminium Alloy Wheel. Modeling of the wheel was done in CAM software Solid works. After the modelling was done, ANSYS was used for the finite element analysis "Material properties were assigned to the component and various s were applied". It was observed that with different values of s, further maximum stresses and minimum cycles were produced in the prosthesis. Keywords- Aluminium Alloy Wheel, A356, FEA, CATIA, ANSYS I. INTRODUCTION The wheel is a device that enables efficient movement of an object across a surface where there is a force pressing the object to the surface. Early wheels were simple wooden disks with a hole for the axle. Because of the structure of wood a horizontal slice of a trunk is not suitable, as it does not have the structural strength to support weight without collapsing; rounded pieces of longitudinal boards are required. The spoke wheel was invented more recently, and allowed the construction of lighter and swifter vehicles. Alloy wheels are automobile wheels which are made from an alloy of aluminum or magnesium metals (or sometimes a mixture of both).alloy wheels differ from normal steel wheels because of their lighter weight, which improves the steering and the speed of the car, however some alloy wheels are heavier than the equivalent size steel wheel. Alloy wheels are also better heat conductors than steel wheels, improving heat dissipation from the brakes, which reduces the chance of brake failure in more demanding driving conditions. Over the years, achieving success in mechanical design has been made possible only after years of experience coupled with rigorous field-testing. Recently the procedures haves significantly improved with the emergence of innovative method on experimental and analytical analysis. Alloy wheels intended for normal use on passenger cars have to pass three tests before going into production: the dynamic cornering fatigue test, the dynamic radial fatigue test, and the impact test. Many alloy wheels manufacturing company had done numerous amount of testing of their product but their method on simulation test on alloy wheel information often kept limited. Alloy wheels were first developed in the last sixties to meet the demand of race track enthusiasts who were constantly looking for an edge in performance and styling. Aluminum wheels should not fail during service. Their strength and fatigue life are critical. In order to reduce costs, design for light-weight and limited-life is increasingly being used for all vehicle components. In the actual product development, the rotary fatigue test is used to detect the strength and fatigue life of the wheel. Therefore, a reliable design and test procedure is required to guarantee the service strength under operational conditions and full functioning of the wheel. Loads generated during the assembly may cause significant levels of stress in components. Under test conditions, these high levels of stress alter the mean stress level which in turn, alters the fatigue life and critical stress area of the components as well. II. PROBLEM FORMULATION This project will be focus on simulating the nature of alloy wheel during operation on road. A range of variables and parameter will be accounted in the simulation. These testing methods provide information on the stress analysis of the alloy wheel in different situation when the wheel is rotating at different rpms. Stress occur on the rim under radial load determine the performance characteristic of an alloy wheel for structural integrity. A wheel should maintain structural integrity without any cracks or plastic deformation. Under a radial load, the strength of the rim usually determines the fatigue life of a wheel, so the stress and fatigue evaluation is focused on the rim. III. STATIC STRUCTURAL ANALYSIS Static Structural Loading Condition: This test is performed to analyse the effect of static force acting on the wheel. The static force being applied on the wheel is to simulate an incident of an attempt to break the wheel by exertion of pressure on the outer periphery. In physical test conditions, the wheel is supported on the hub along with the bolts and a pressure at the outer periphery is applied on it by the air. The direction of the pressure is normal ISSN 2278-5787 ge 66
w.r.t. the axis of rotation. The point of loading is at the outer periphery of the wheel. This loading is done in ANSYS Workbench 15. The value of the pressure to be entered in ANSYS Workbench 15 in the Pressure tab can be seen in Figure. Figure shows the direction of force and the selected geometry for application of load. Image showing pressure applied on selected model geometry in ANSYS Workbench 15 The boundary conditions can be defined as the supports and displacement constraints that are applied in order to fix any degrees of freedom of the model. This condition can be simulated by applying a Fixed Support and a cylindrical support to the required geometry as seen in Figure Image showing boundary conditions applied on the model in ANSYS Workbench 15 Static Analysis A static structural analysis determines the displacements, stresses, strains, and forces in structures or components caused by loads that do not induce significant inertia and damping effects. Steady loading and response conditions are assumed; that is, the loads and the structure's response are assumed to vary slowly with respect to time. A static structural load can be performed using the ANSYS. The types of loading that can be applied in a static analysis include: Externally applied forces and pressures Steady-state inertial forces (such as gravity or rotational velocity) Imposed (nonzero) displacements Temperatures (for thermal strain) A static structural analysis can be either linear or nonlinear. All types of nonlinearities are allowedlarge deformations, plasticity, stress stiffening, contact (gap) elements, hyper elasticity and so on. This chapter focuses on linear static analyses with brief references to nonlinearities Material properties can be linear or nonlinear, isotropic or orthotropic, and constant or temperature-dependent. You must define stiffness in some form (for example, Young's modulus, hyper-elastic coefficients, and so on). For inertial loads (such as Standard Earth Gravity), you must define the data required for mass calculations, such as density. A rigid part is essentially a point mass connected to the rest of the structure via joints. Hence in a static structural analysis the only applicable loads on a rigid part are acceleration and rotational velocity loads. You can also apply loads to a rigid part via joint loads. The output from a rigid part is the overall motion of the part plus any force transferred via that part to the rest of the structure. Rigid behavior cannot be used with the Samcef solver. If your model includes nonlinearities such as large deflection or hyperelasticity, the solution time can be significant due to the iterative solution procedure. Hence you may want to simplify your model if possible. For example you may be able to represent your 3D structure as a 2-D plane stress, plane strain, or axisymmetric model or you may be able to reduce your model size through the use of symmetry or anti-symmetry surfaces. Similarly if you can omit non-linear behavior in one or more parts of your assembly without affecting results in critical regions it will be advantageous to do so. Provide an adequate mesh density on contact surfaces to allow contact stresses to be distributed in a smooth fashion. Likewise, provide a mesh density adequate for resolving stresses; areas where stresses or strains are of interest require a relatively fine mesh compared to that needed for displacement or nonlinearity resolution. If you want to include nonlinearities, the mesh should be able to capture the effects of the nonlinearities. For example, plasticity requires a reasonable integration point density (and therefore a fine element mesh) in areas with high plastic deformation gradients. For a static structural analysis applicable loads are all inertial, structural, imported, and interaction loads, and applicable supports are all structural supports. For the same of solver, the following loads and supports are not available: Hydrostatic Pressure, Bearing Load, Bolt Pretension, Joint Load, Fluid Solid Interface, Motion Loads, Compression Only Support, Elastic Support. Loads and supports vary as a function of time even in a static analysis as explained in the Role of Time in Tracking. In a static analysis, the load s magnitude could be a constant value or could vary with time as defined in a table or via a function. Details of how to apply a tabular or function load are described in Defining Boundary Condition Magnitude. In addition, see the Apply Loads and Supports section for more information about time stepping and ramped loads. A static analysis can be followed by a pre- ISSN 2278-5787 ge 67
stressed analysis such as modal or linear (eigenvalue) buckling analysis. In this subsequent analysis the effect of stress on stiffness of the structure (stress-stiffness effect) is taken into account. If the static analysis has a pressure or force load applied on faces (3D) or edges (2D) this could result in an additional stiffness contribution called pressure load stiffness effect. This effect plays a significant role in linear (eigenvalue) buckling analyses. This additional effect is computed during the eigen analysis using the pressure or force value calculated at the time in the static analysis from which the perturbation occurs. See the Applying Pre- Stress Effects section for more information on this topic. When performing a nonlinear analysis you may encounter convergence difficulties due to a number of reasons. Some examples may be initially open contact surfaces causing rigid body motion, large load increments causing non-convergence, material instabilities, or large deformations causing mesh distortion that result in element shape errors. To identify possible problem areas some tools are available under Solution Information object Details view. Solution Output continuously updates any listing output from the solver and provides valuable information on the behaviour of the structure during the analysis. Any convergence data output in this printout can be graphically displayed as explained in the Solution Information section. You can display contour plots of Newton-Raphson Residuals in a nonlinear static analysis. Such a capability can be useful when you experience convergence difficulties in the middle of a step, where the model has a large number of contact surfaces and other non-linearity s. When the solution diverges identifying regions of high Newton-Raphson residual forces can provide insight into possible problems. Result Tracker (applicable to Static Structural systems only) is another useful tool that allows you to monitor displacement and energy results as the solution progresses. This is especially useful in case of structures that possibly go through convergence difficulties due to buckling instability. Result Tracker is not available to the Same solver. All structural result types except frequencies are available as a result of a static structural analysis. You can use a Solution Information object to track, monitor, or diagnose problems that arise during a solution. Once a solution is available you can contour the results or animate the results to review the response of the structure. As a result of a nonlinear static analysis you may have a solution at several time points. You can use probes to display the variation of a result item as the load increases. An example might be large deformation analyses that result in buckling of the structure. In these cases it is also of interest to plot one result quantity (for example, displacement at a vertex) against another results item (for example, applied load). You can use the Charts feature to develop such charts. Property of a Material ISSN 2278-5787 ge 68 Sr. No. Property Value Unit 1 Density 2770 Kg m -3 2 Co-efficient of thermal expansion 3 Reference temperature 4 Young s modulus 5 Poisson s ratio 6 Bulk Modulus 7 Shear Modulus 8 Tensile Yield strength 9 Compressive Heat Strength 10 Tensile ultimate Strength 2.3E-05 c -1 22 C 7.1E+10 0.33 6.9608E+10 2.6692E+10 2.8E+08 2.8E+08 3.1E+08 When the wheel is meshed, in estimated data change gradient big spot, it needs to adopt more intensive grid to better reflect the changes of data. In the wheel hub, the danger zones are rim, junction with rim and rib, and the areas around bolt hole. The process of dividing the object in to different elements is called meshing. Meshing involves division of the entire of model into small pieces called elements. This is done by meshing. Meshing thus holds a very important place in the finite element analysis. An in-depth study of meshing assumes a very important role. The wheel is meshed using SOLID element size is 5mm. The number of elements was found to be 208273 and the number of nodes was found to be 347677. Meshing in alloy wheel model Result and discussion Change in Cycles w.r.t. Alternating Stres Alternating Stress Cycles (Mpa) 24076 225
. Alternating Stress 7000 Cycles (Mpa) 34527 213 6000 51601 201 5000 77110 182.5 4000 1.886e+05 170 3000 1.8509e+05 162 2000 2.9425e+05 151 1000 5.1319e+05 134 0 5.1319e+05 134 8.7774e+05 120 1 3 5 7 9 1.7667e+06 105 3.2e+06 90 Total Deformation Alternating Stress vs Cycle Effect on Total Deformation wrt Various values of s were changed inthe model and the total deformation were computed with the help of ANSYS workbench. The changes made and their respective effects are shown in the figures as follows: The maximum equivalent stress in the wheel is increasing with increase in pressure as shown in the table. Change in Total Deformation w.r.t. Total Deformation 2000 0.44180 2500 0.44876 3000 0.4552 3500 0.46116 4000 0.46661 4500 0.47153 5000 0.47591 5500 0.47973 6000 0.48299 6500 0.48566 Maximum Total deformation at 30000 The maximum Total Deformation at 3000 can be seen in Figures.The maximum Total Deformation at 3000 is found to be 0.4552. Total Deformation w.r.t. Effect on Stress wrt Pressure Various values of pressure were changed in the model and the Maximum equivalent stresses were computed with the help of ANSYS Workbench keeping constant 4000. The changes made and their respective effects are shown in the figures as follows Table The maximum equivalent stress in the wheel is increasing with increase in pressure as shown in the table. Change in Max equivalent stress w.r.t. Pressure Pressure (M) Max. Equivalent Stress(Mpa) 0.5 41.78 1 46.16 1.5 67.89 2 92.64 Maximum equivalent stress at pressure 0.5 Mpa Total Deformation CONCLUSION From the study carried out, the following broad conclusions are arrived. A suitable alternative to the traditional techniques of testing and experimentation by using Finite Element Analysis (FEA). The results calculated by using FEA are close to the experimental results calculated using traditional methods of the areas of maximum stress can be easily visualised with the help of FEA and the accuracy of results by using the sub-modelling technique depends on meshing of the geometry model and defining the physical and material property values. The study of effects of various variations in the model using FEA is cost effective and time saving as compared to traditional techniques. Following result or obtained: ISSN 2278-5787 ge 69
A fatigue lifetime prediction method of aluminium alloy wheels was proposed to ensure their durability at the initial design stage. FEM model was built using Ansys to simulate the rotary fatigue test, static load. In analysis results we can see that the maximum stress area was located in the hub bolt hole area agreed with the fact. Therefore, the results achieved by actual static load test and the results of finite element model are consistent to each other. The prediction the fatigue life of aluminium alloy wheels is done with the help of nominal stress method. In the nominal stress method, the fatigue life of aluminium wheels was predicted by using aluminium alloy wheel S-N curve and equivalent stress amplitude. The baseline design fatigue life was lower than 1 10 5 according to the simulation results. After improving the weakness area of aluminium alloy wheels, the improved wheel life cycle exceeded 1 10 5 and satisfied the design requirement. Aluminium alloy wheel rotary fatigue bench test was conducted. The test result showed that the prediction of fatigue life was consistent with the physical test result. The test result shows that with increase in value of pressure the value of Maximum equivalent stress is increasing. These results indicate that the fatigue life simulation can predict weakness area and is useful for improving aluminium alloy wheel. These results also indicate that integrating FEA and nominal stress method is a good and efficient method to predict aluminium alloy wheels fatigue life. FUTURE SCOPE Recommendations for Future Research The benefits of Finite Element Analysis are numerous. In this study the emphasis is laid just on static structural and fatigue analysis on an aluminium alloy wheel but this can be carried forward for further research. Here are some of the recommendations for future research: 1. Impact/crash test can be done,. 2. Vibration considerations can be done at different s. Future Scope The scopes of the project are:- 1. Optimization of fly whell can be done. 2. The methodology can be practically validated for the value of stress by using strain gauge. 3. Transient analysis can be done to check the effect of change of time. 4. Design of the automotive alloy wheel using CAD software product is generally used in automotive industry (14, 15, 16 inch alloy wheel, 6 inch wide, 5~8 spokes) 5. Simulation data collection using FEA software 6. Analysis of stress and fatigue of alloy wheel. REFERENCES [1]. N. Satyanarayana & Ch. Sambaiah-.Fatigue Analysis of Aluminium Alloy Wheel Under Radial Load, International Journal of Mechanical and Industrial Engineering (IJMIE), ISSN No. 2231 6477, 2012,Vol-2, Issue-1. [2]. J. Janardhan, V. Ravi Kumar, R. Lalitha Narayana- Radial Fatigue Analysis of An Alloy Wheel, J. Janardhan et al. Int. Journal of Engineering Research and Applications www.ijera.com ISSN : 2248-9622, Vol. 4, Issue 12( rt 6), December 2014, pp.253-258. [3]. T. Siva Prasad, T. Krishnaiah, J. Md. Iliyas, M.Jayapal Reddy-A Review on Modeling and Analysis of Car Wheel Rim using CATIA & ANSYS, International Journal of Innovative Science and Modern Engineering (IJISME) ISSN: 2319-6386, May 2014 Volume-2, Issue-6. [4]. P. Meghashyam1, S. Girivardhan Naidu2 and N. Sayed Baba3- Design and Analysis of Wheel Rim using CATIA & ANSYS, International Journal of Application or Innovation in Engineering & Management (IJAIEM)Volume 2, Issue 8, August 2013 ISSN 2319 4847. [5]. Ravi Lidoriya, Sanjay Chaudhary and Anil Kumar Mohopatra- Design and Analysis of Aluminium Alloy Wheel using PEEK Material, International Journal of Mechanical Engineering and Research. ISSN No. 2249-0019, Volume 3, Number 5 (2013), pp. 503-516. [6]. M.V. Prabha and Pendyala Veera Raju-Design and development of aluminium alloy wheels, International Journal of Advanced Science, Engineering and Technology. ISSN 2319-5924, Vol 1, Issue 2, 2012, pp 55-60. [7]. P. Ramamurty Raju a,*, B. Satyanarayana b, K. Ramji b, K. Suresh Babu a -Evaluation of fatigue life of aluminium alloy wheels under radial loads, Engineering Failure Analysis 14 (2007) 791 800. [8]. Hement tel1, Rajesh Kumar Satankar-Failure analysis of Steel Wheel by using finite Element Method, International journal of research in aeronautical and mechanical engineering vol.2 issue.6,2014,pgs:106-115. [9]. M.M. Topaç, S. Ercan, N.S. Kuralay-Fatigue life prediction of a heavy vehicle steel wheel under radial loads by using finite element analysis, Engineering Failure Analysis 20 (2012),67-79. [10]. Rahman, A. R., Tamin, M. N., &Kurdi, O. -Stress analysis of heavy duty truck chassis as a preliminary data for its fatigue life prediction using FEM. Journal Mekanika (2008), 76-85. ISSN 2278-5787 ge 70