MODELLING AND SIMULATION OF SHOCK ABSORBER FOR NOISE RECTIFICATION ANALYSIS
D. KUMAR YOGEESH *
Department of Engineering, FEAM, Nilai University, 71800, Nilai, Malaysia.
B. R. RAMESH BAPU
Department of Mechanical Engineering, CIT, 600069, Chennai, TN, India.
K. ERIKI ANANDA
Department of Mech. and Ind. Engg, Caledonian College of Engineering, Muscat, Sultanate of Oman.
*Author to whom correspondence should be addressed.
Abstract
A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy. The shock absorber noise problem was planned to be identified and rectified using Finite element simulation method. Initially the cause of this problem was believed because of vibration of the spring. Free-free modal analysis of the spring was conducted and it was identified that spring frequency was not the reason for 3Hz noise. Then free-free modal analysis of the shock absorber assembly and other components were done. The first natural frequency of the shock absorber assembly and other components were not near 3 Hz. Then the dynamic analysis of the shock absorber was done to find out whether there is any buckling or contact issue. During dynamic analysis there was buckling effect in the spring which scratched the inner rod and created 3 Hz noise. Customer constrained us not to change the material or redesign the spring. Work allowed changing the design of nylon end cap only. We designed different nylon end cap by varying the length and conducted the dynamic analysis with the modified end cap. The buckling effect and hence 3Hz noise was eradicated while conducting dynamic analysis using 40 mm long nylon end cap.
Keywords: 3 Hz noise, shock absorber, free-free model analysis