Stiffness weak link identification of cantilever beam based on vibration test data

摘要

The evaluation of the weak link of machine tool structural stiffness is the key link to improve the machining performance of the machine tool.It is proposed that the serial structure of the machine tool be equivalent to a cantilever beam structure and the static rigidity of the machine tool be studied by using the method of dynamic test.A theoretical method for evaluating the position of the weak link of cantilever beam stiffness and the magnitude of stiffness by using the curve angle index is proposed.This paper mainly studies the evaluation effect of indicators.Taking the MATLAB finite element numerical model of cantilever beam structure as a numerical example,the dynamic test data of each node of the numerical model are obtained by using the state space method.After Fourier transform,the angle index is studied by taking the amplitude of 0 Hz.The weakening of the elastic modulus of the element is used to simulate the weak link of stiffness,and the evaluation effect of the corner index is studied under the three conditions of weakening the stiffness of a single element,weakening the stiffness of two elements,weakening the stiffness of three elements and involving noise.The results of simulation and experiment show that the curve angle can be used to better evaluate the weak link of the cantilever beam,which has a certain practical value in engineering.