THE APPLICATION OF SENSITIVITY ANALYSIS TO MODIFYING CAR BODY CONFIGURATION

摘要

In this paper, three dimensions CAD model of a car body is built up with UG software. The model is inputted into ANSYS program by port. After the model is modified properly, it can be meshed. It is necessary for modal analysis to define material] real constants and constraints etc. Then we can launch the ANSYS solver to calculate the model. The modal parameters (modal frequency and mode shape) are gained. Their validity is verified by modal test. On above base, structure modification and optimization are carried out. According to the theory of interior cumulation relativity, their mode shape and frequency relativity is calculated. The degrees of relativity determine if the finite element model can substitute the prototype or not. According to request of exposing environment, its first order frequency must less than 23Hz,but the actual value is 24Hz, so the adjustment must be made. Sensitivity method is used to modify body structure. The values of sensitivity to thickness of sheetmental are calculated. The parameters of thickness corresponding to larger value are regarded as design variables. The anticipant target is minimum expense.