International Journal of Engineering Research ISSN:2319-6890)(online),2347-5013(print) Volume No.5, Issue No.2, pp : 123- 126 1 Feb. 2016 doi : 10.17950/ijer/v5s2/211 Page 123 Analysis of Coil Spring Used in Shock Absorber using CAE Dr. Dhananjay. R. Dolas , Kuldeep. K. Jagtap JNEC,Aurangabad Abstract: Vehicle suspension system has to perform complexity requirements, which includes road holding and equality, driving pleasure, riding comfort to occupant. The objective of this paper is to analyze the performance of Shock absorber spring by varying stiffness, which is obtained by doing optimization using Genetic Algorithm as optimization tool to obtain maximum ride comfort. The Shock absorber is one of the suspension systems designed mechanically to handle shock impulse and dissipate kinetic energy. It reduces the amplitude of disturbances leading to increase in comfort and improved ride quality. The spring is compressed quickly when the wheel strikes the bump. The compressed spring rebound to its normal dimension or normal loaded length which causes the body to lift. The spring goes down below its normal height when the weight of the vehicle pushes the spring down, spring resist deformation. Modeling and analysis is done using Pro E and ANSYS respectively. Keywords: Coil spring, Stiffness, Modelling & FEA Introduction: Suspension system plays an important role for a comfortable ride for passengers besides protecting the chassis and other working parts from getting damaged due to road shocks. If in a vehicle both front and rear axles are rigidly fixed to the frame, while vehicle is moving on the road, the wheels will be thrown up and down due to the irregularities of road, as such there will be much strain on the component as well as the journey for the passengers in the vehicle will also be very uncomfortable. This is the system that provide comfortable ride and also prevent damage to the working parts. Literature Review In this section, literatures survey study gathered regarding the information about the stress for the helical compression spring. Springs are mechanical shock absorber system. A mechanical spring is defined as an elastic body which has the primary function to deflect or distort under load, and to return to its original shape when the load is removed. The researchers throughout the years had given various research methods such as Theoretical, Numerical and Experimental. Researchers employ the Theoretical, Numerical and FEM methods. Study concludes Finite Element method is the best method for numerical solution and calculating the stress, life cycle and shear stress of helical compression spring Lavanya et al. [1] presented the work to analyze the safe load of the light vehicle suspension spring with different materials and investigation includes comparison of modeling and analyses of primary suspension spring made of low carbon-structural steel and chrome vanadium steel and suggested the suitability for optimum design. The results showed that reduction in overall stress and deflection of spring for chosen materials. Youli Zhu et al.[2] analyzed compression coil spring fractured at the transition position from the bearing coil to the first active coil in service, Visual observations indicated that a wear scar was formed on the first active coil and the fracture surface showed radiating ridges emanating from the wear scar. Scanning electron microscopy examination showed crescent shaped region and beach marks, typical of fatigue failure. Chavan et al. [3] determine the fatigue life of the existing coil spring on the car and identify areas of improvement over the fatigue life. Finite Element Analysis would be deployed for the structural analysis using NASTRAN or suitable solver while the fatigue life would be predicted using `MSC Fatigue' or suitable. For this work, experimentation shall be performed for validating the performance parameter identified as `Stiffness' of the spring. The load vs. displacement shall be recorded using load cells with data logger to display results. Kannan et al. [4] presented shock absorber modeling using SOLID WORKS and analysis done in ANSYS. Structural analysis is done on the shock absorber for various material, Spring Steel and Carbon fiber. Suryawanshi et al. [5] considered the four variants of spring as its application is in the dies to hold the metal sheet during blanking (stamping) operation. One of the variant is considered as standard specimen and accordingly study and design analysis of standard specimen is done (In Hypermesh, NASTRAN and MSC Fatigue), by finding the both static force and dynamic forces in terms of fatigue life. Mehdi et al.[6] worked on optimum design of steel helical spring related to light vehicle suspension system under the effect of a uniform loading has been studied and finite element analysis has been compared with analytical solution. The spring has been replaced by three different composite helical springs which are made of Eglass/Epoxy, Carbon/Epoxy and Kevlar/Epoxy. The optimum design based on the parameters of weight, maximum stress and deflection and has been compared with steel helical springs. It has been shown that spring optimization by material spring changing causes reduction of spring weight and maximum stress considerably. Mulla et al. [7] presented the static stress analysis using finite element method has been done in order to find out the detailed stress distribution of the spring. Pharne et al. [8] study under fatigue loading condition. Fatigue analysis is done in ANSYS 14.0 software. The results are compared with the experimental observations. A new design modification is done by introducing another spring coaxially. Gaikwad et al. [9] presented the analysis of safe load of the helical compression spring. A typical helical compression spring configuration of two wheeler horn is chosen for study. This work describes static analysis of the helical compression spring is performed using NASTRAN solver and compared with analytical results. The pre processing of the spring model is done by using HYPERMESH software. Achyut et al. [10] worked on the shock absorber designed and a 3D model is created using Pro/Engineer. Structural analysis and modal analysis are done on the shock absorber by varying material for spring, Spring Steel and Phosphor Bronze. Structural analysis is done to validate the strength and modal analysis is done to determine the displacements for different