Modal Analysis and Model Updating Studies on a Three-Wheeler Auto

Abstract

Three-wheelers (auto rickshaws) are light and inexpensive vehicles capable of carrying up to three passengers or a cargo of 6,000 Newton and are mostly found in developing countries. Experimental modal analysis was carried out on a newly designed diesel auto rickshaw mainly to validate and update the finite element model of the auto chassis. With 495 degrees of freedom, the finite element model stiffness matrix was updated using the first four eigenvalues and eigenvectors measured at 63 points. Difficulties involved in model updating of complex structures using incomplete measured data have been discussed. Eigensolution with an updated model produces natural frequencies close to the measured values. Mass and stiffness modification studies were carried out on the updated model to simulate a fully loaded vehicle and were correlated with the resonant peaks experienced when the fully loaded auto was running at 30 kmph on typical bad roads.