International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056 Volume: 02 Issue: 06 | Sep-2015 www.irjet.net p-ISSN: 2395-0072 © 2015, IRJET ISO 9001:2008 Certified Journal Page 58 Probabilistic design of helical coil spring for Translational invariance by using Finite Element Method Sagar N Khurd, Prasad P Kulkarni, Samir D Katekar 1Research scholar, Department of mechanical Engineering, SKN Sinhgad College of Engineering, Korti, 2Department of mechanical Engineering, SKN Sinhgad College of Engineering, Korti, Pandharpur , 3Department of mechanical Engineering, SKN Sinhgad College of Engineering, Korti, Pandharpur , ---------------------------------------------------------------------***--------------------------------------------------------------------- Abstract - The study represents new approach to design helical coil spring by using workbench. Response surface modeling and analysis of helical spring by considering Translational invariance have been carried out. In previous paper we had considered longitudinal invariance. Design parameters are wire diameter, coil diameter, height, number of turns elastic modulus in X and Y direction, force. Simple equation is proposed which gives value of compressive stress of helical coil spring by carrying out regression analysis done by M S excels, It is observed that force and material property are significant parameters which affect compressive stress because their P value is 1. Relationship among design parameters and compressive stress has been obtained. In this analysis it is observed that coil diameter increases stress on the the spring decreases. Key Words: - Analysis by FEA and Response surface modeling, Simulation. I.INTRODUCTION Spring act as a flexible joint in between two parts or bodies. Spring is the energy storing and releasing element whenever required. This paper demonstrates by taking the combination of steel and composite material for design of helical compression spring. In this case instead of steel is used combination of steel and composite material Glass fiber/Epoxy because of low stiffness of single composite spring, which limits its application to light weight vehicle only. Composite material is light weight and corrosion resistance, it can withstand high temperature. It increase efficiency of vehicle and overcome the cost. He had concluded combination of steel and composite material can increase the stiffness which is the major requirement of regular vehicle due to higher weight this done by using the FEA.[1].This study investigates static behavior of helical structure under axial loads. In this paper, authors have taken two helical structure first one is single wire on which homogeneous theory applied and second is axial elastic properties of seven wire strand are computed. This approach, based on asymptotic expansion, gives the first- order approximation of the 3D elasticity problem from the solution of a 2D microscopic problem posed on the cross- section and a 1D macroscopic problem, which turns out to be a Navier–Bernoulli–Saint-Venant beam problem and result compared with reference results.[2] This paper researchers taken four composite material (structure)these are unidirectional laminates (AU), rubber core unidirectional laminates (UR), Unidirectional laminates with braided outer layer (BU), and rubber core unidirectional laminates with braided outer layer (BUR). They investigated effect of rubber core and braided outer layer on the mechanical properties of the above mentioned helical springs. According to the experimental results, the helical composite spring with a rubber core can increase its failure load in compression by about 12%; while the spring with a braided outer layer cannot only increase its failure load in compression by about 18%, but also improve the spring constant by approximately 16%. [3]This study deals with the stress analysis of a helical coil compression spring, which is employed in three wheeler’s auto-rickshaw belonging to the medium segment of the )ndian automotive market. This spring’s have to face very high working stresses, so in this design of the spring both the elastic characteristics and the fatigue strength have to be considered as significant aspects. This done by using finite element analysis. These springs have to face very high working stresses. The structural reliability of the spring must therefore be ensured. [4]The linear zed disturbance equations governing the resonant frequencies of a helical spring subjected to a static axial compressive load are solved numerically using the transfer matrix method for clamped ends and circular cross-section to produce frequency design charts.This paper summarize the behavior of the lowest resonant frequency obtained from the model of a helical compression spring with an initial number of turns.[5]In this paper, long term fatigue test on shot peened compression spring were conducted by means of special spring fatigue testing machine at 40 Hz. Three different types of material is taken and the influence of different shot peening conditions were investigated. In this paper fractured test spring were