Modal analysis of a truck cab using the least squares complex exponent test method

Abstract

This article introduces the basic theory of modal analysis. The modal testing system is established for a developing truck body. Using a pseudo-random excitation signal along the x, y, and z directions, the modal test is carried out to obtain the dynamic performance by multi-point excitations. The transfer function set is obtained by averaging all transfer functions, and the set is processed by order selection to get 28 order modes. Fitting modal parameters and normalizing modal mass can gain natural frequencies and vibration modes of cab. Then, the modal analysis of truck cab is calculated based on the finite element method, and the results are compared with the test results. The improved measures are put forward to enhance the local stiffness, avoid modal coupling, and reduce vibration noise. So, this article supplies a reference for the dynamic test for the large body.