关键词: 车架；零阶优化；一阶优化；模态分析；模型修正

Abstract: In the modal analysis of vehicle frames using the finite element method, discrepancies between finite element calculation results and experimental test results inevitably arise due to factors such as uncertainty in material properties, simplifications in modeling and boundary conditions. This paper takes a newly developed special-purpose vehicle frame as the research object, establishes a fully parametric model, and employs a combined zero-order and first-order optimization method to update the finite element model of the frame based on experimental data. Taking the sum of frequency errors at each order as the objective function, material density, Young's modulus, and wall thickness are selected as design variables, while model mass error, individual frequency errors at each order, and modal assurance criterion are used as state variables for iterative computation. The results show that the objective function value decreases from 39.68% to 8.33%, the maximum single-order frequency error decreases from 6.03% to 2.13%, and the minimum modal assurance criterion (MAC) value corresponding to each order mode is 0.955. The updated frame model can be used for subsequent dynamic studies.

Key words: vehicle frame; zero-order optimization; first-order optimization; modal analysis; model updating