CAE Analysis and Structural Optimization of PitmanArm

International Engineering Research Journal Page No 1-5CAE Analysis and Structural Optimization of PitmanArm Sijith PM1, Prof. Shashank Gawade2, Prof. S.S Kelkar3 1, 2, 3 Mechanical Engineering 1, 2, 3 ’ JSPM S Jayawantrao Sawant College of Engineering, Hadapsar, Pune, India. [email protected] [email protected] [email protected] Abstract— Steering system is used to steer the front wheels in dynamics approach for design reduces time for optimization, response to driver inputs in order to provide overall directional simulation and provide the chance to take most corrective control of the vehicle. Thus, Steering system plays very action. Rigid dynamics approach is used in modern design important role in vehicle handling characteristics. Pitman arm techniques for various domains plays a very important role in steering system as it transmits the Girish Rane and K.M. Narkar[3] investigated the steering arm steering movement to the wheel. The Pitman arm is a linkage attached to the sector shaft of the steering box and track rod, and pitman drag link ball joint affects these parameters and that converts the angular motion of the sector shaft into the prove that the location of the steering arm ball joint affects linear motion needed to steer the wheels. vehicle directional stability in severe brake applications The Pitman arm is supported by the sector shaft and supports Malge Sangeeta Ganesh, G. P. Patil B and N. A. Kharche[2] the drag link or center link with a ball joint. It transmits the analyzed various structural analyses such as static-structural, motion it receives from the steering box into the drag (or center) modal Analysis of a steering rod are done. Static-structural link, causing it to move left or right to turn the wheels in the analysis is capable to find out deformation in body in which appropriate direction. Performance study is carried out followed Von-mises stress are calculated and this state that up to what by static structural analysis and optimization to minimize the extent the deformation in the rod occurs. weight of the pitman arm and thereby reducing the material cost. Optimized model is then verified by physical testing. Cristina Elena Popa[6] investigated the current automotive steering and suspension systems followed by the review of I. INTRODUCTION Formula SAE-A restrictions and design requirements. A thorough analysis of 2004 USQ racer car has been included in The pitman arm is also called steering arm, it is a linkage order to establish the areas of design modifications followed which is attached at one side to the steering box (through by the actual design with all the technical specifications sector shaft) at the bottom of the steering wheel shaft and on required. the other side to the track rod which is attached at the other end to the idler arm. When the steering wheel is turned left or III. OBJECTIVES OF THE WORK right, a worm gear at the bottom of the steering shaft turns a set of teeth. That action moves a gear that activates the pitman 1. To study and perform static analysis on pitman arm under arm, causing the steering linkage to move the wheels. steering load. The steering arm is part of an older recirculating ball steering 2. To propose an optimized model which will have better or system which is still used primarily in some full-size SUVs same performance and reduced weight. and trucks as compared with the smoother-handling rack and pinion steering mechanism more commonly used in IV. SCOPE OF THE WORK automobiles. A properly functioning pitman arm, 1) precisely directs the 1. Numerical analysis: Static analysis and topology movement of all the other steering links, 2) limits wheel optimization is performed on the existing pitman arm wobble on bumpy surfaces, 3) assures full wheel turning model using FEA tools. radius and 4) helps to reduce steering wheel vibration. 2. Theoretical verification: Verifying the FEA analysis using hand calculation. II. LITERATURE SURVEY 3. Experimental analysis: Making the optimized geometry, physically testing it under the same loading conditions Various studies have been carried out to understand Pitman and verifying the test and analytical result. arm function and load condition. V.D.Thorat and S.P.Deshmukh[1] analyzed rigid multi body dynamic analysis approach in design and Results shows rigid Element Type. Recreational Vehicles VI. ADVANTAGES OF PITMANARM 1. INTENDED APPLICATION 1. Discretize the model by meshing. Pitman arm combined with power steering mechanism could be better than a rack and pinion mechanism Fig. First Order (Linear) Fig.3. VII.0 and Optistruct tools. 6. MODELLING AND ANALYTICAL TOOLS USED IX. Finite element analysis is performed using Hypermesh 3. Heavy Duty Equipment 12. Provides mechanical advantage to the driver 5. Hexahedron & Wedge (Prism) Element Order. FEM ANALYSIS OF PITMAN ARM Finite element analysis is a computational technique used to obtain approximate solutions of boundary value problems in Fig. Simple in Design 4. 8. Define the geometry of the problem. 4. 7.4. Less Sensitive to errors in assembly 3. Solve the analytical problem. 3. Higher turning Ratio 2. Truck Steering 2. Define the material properties of the elements. Carbon steels VIII. Passenger Car Steering Parametric 2. 2. International Engineering Research Journal Page No 1-5 V.0. Element population count. 3D Modelling of the pitman arm is made using Creo 1. Define the element connectivity. Pitman arm vehicle assembly Node Population Count. Define the loadings. Result evaluation. Iron 3. 5. Define the element type(s) to be used.2. 4. 9. Steering Linkage Components [3] engineering. Pitman Arm side View X.19750. COMMON MATERIAL USED FOR PITMANARM 1. Alloy steel 2. Meshing . Define the physical constraints (boundary conditions). 2. These are the steps for pre and post processing in FEM 1.1.23887. PITMANARM ASSEMBLY Fig. MATERIAL PROPERTIES Material used for Pitman Arm is Alloy Steel – 4140. based on an objective function and subject to certain M/I = /y design constraints. calculated in a finite element analysis. B= 215mm Center of rotation (king pin) to wheel. Since single steering arm will be handling two wheels so force on steering arm will be doubled F= 6781 N. M= 504kg which is very close to the calculated value (258MPa). F= Force on steering arm. M1= 1640+680+200 = 2520kg Mass on the front axle. Yield strength of the material is 520MPa and stress I= Moment of Inertia value obtained is just half of the yield strength. International Engineering Research Journal Page No 1-5 XI.59e3 mm4 XIII. Maximum Bending Moment (M) calculation: Thickness t = 15mm Fig. Load=6781N is applied (from the side) at as we needed.6N. Topology Optimization is a mathematical technique that optimized the material distribution for a structure within a given package space. and manufactured by forging TABLE 1 MATERIAL PROPERTIES Density of Material 7. µ= 0. M2=1008kg Von Mises stress observed from the FE analysis = 255 MPa Mass on one of the front wheel. Boundary Condition and Loading Total Mass of the vehicle.3 Yield Strength 520MPa XII.5 N.Von Mises Stress Plot Width b= 35mm Numerical stress value closely matched with analyzed stress Length L = 120mm value.6. Width of tire. F = T/L1 = 3390. . There are many different methods that can Maximum Bending Stress  = 258 MPa be used to optimize a structure. I = (t*b3) /12 I= 53.5. OPTIMIZATION M =F * L =6781*120 Optimization is a process to make a component possibly =813720 N-mm perfect. Optistruct tool is selected for the optimization as this software allows the use of numerous structural responses. E= 120mm Co-efficient of friction. we have selected Topology The hole which is connected to sector shaft of steering box is optimization as it is more suitable to apply design constraints fully constrained. or combination of these responses to be used as objective and constraint functions in a structural optimization. BOUNDARY CONDITION AND LOADING Fig. L1= 145mm.85e-6 kg/mm3 Modulus of Elasticity 210 GPa Poisons Ratio 0. So it shows the scope for the optimization of the existing pitman arm. T=M*g*µ* ((B2/8) + E2) T=Torque required to rotate one wheel (torque at king pin). T= 491629. [4] For Pitman arm optimization. the other end of the pitman arm.7 Distance from king pin center to tie rod center. Optimization rear side wire cut EDM technique (Since it is a forged part). Strain gauge mounting .11.9.7. Von Mises Stress Plot Fig.8. Hexahedron & Wedge (Prism) Element Order. International Engineering Research Journal Page No 1-5 Fig. Optimized model with weld connection Element Type. First Order (Linear) Node Population Count.13. In the above figure 9 and 10 (optimized model). XIV. TESTING AND VALIDATION Optimized pitman arm is made from the existing part using Fig.12. Machined Pitman Arm After machining. Optimization top side Fig. material can be removed from area colored in dark blue.39265. Average Principle strain plot Obtained strain for optimized model is 1600µe.10. Fig. surface preparation is done to locate and paste the strain gauge on pitman arm Fig.45306 Element population count. Fig. P. Issue 1. REFERENCES [1] V. Procedia Engineering 15 (2011) 1030 – 1035 [6] Cristina Elena Popa. “Performance of the Structural Analysis of Ford Car Steering Rod”. International Journal of Research in Advent Technology. K. Vol. A. Feb-Mar. “Dynamic Modeling and Steering Performance Analysis of Active Front Steering System”.D. pitman arm is attached to a fixture new pitman arm design could be used instead of the by welding in such a way to locate it in UTM properly and current one. “Steering System and Suspension Design For 2005 Formula SAE-A Racer Car”. “Rigid Body Dynamic Simulation of Steering Mechanism”. N.14.M. Liping Chen “Analysis and Optimization of the Double-Axle Steering Mechanism with Dynamic Loads”. Narkar. XV.2. Volume 3. 6. load applying by UTM Fig. Also the static analysis result of the optimized model was well correlating with the test result which proves that the . “Steering System Optimization for Vehicle Drift”. 2015. February 2014 E-ISSN: 2321-9637 [3] Girish Rane. Initial static analysis result and calculated stress values are closely matching which shows that the boundary conditions and force calculations were right. University of Southern Queensland. Issue-5. 2. Pitman Arm attached in fixture 5747.15. Patil B. Jun Wang. then to apply the load on other side. a weight reduction of about 120g is achieved which saves the material cost. Through optimization. Fig.Thorat. 2014 [4] Yunqing Zhang. Kharche. Deping Wang. G. the Open Mechanical Engineering Journal. Ird India. Gang Qin. 2012. P. S. Elseveir. Strain gauge reading after load application. ISSN: 2320 – 8791 [2] Malge Sangeeta Ganesh.16. No.2. ISSN: 2321- Fig. International Journal of Research in Engineering & Advanced Technology. CONCLUSIONS Optimization of the pitman arm is carried out and below are the conclusions from the analysis and testing: 1. Volume-2. 3. (Suppl 1-M2) 26-39 [5] Zhenhai Gao. The measured strain value from gauge is 1568 µe. October 2005. Ying Sun.Deshmukh. International Engineering Research Journal Page No 1-5 After strain gauge pasting.