Research Of Equivalent Model Of Brazed Aluminum Honeycomb Sandwich Panel And Application

Lightweight rail transit vehicle body structure is an eternal theme.The application of brazed aluminum honeycomb sandwich panels in the load-bearing structure of the vehicle body is an effective way to achieve lightweight.Considering the characteristics of the real geometric structure,the period of refined modeling of the honeycomb structure is long and the calculation conditions are demanding,so the application of the equivalent model has attracted attention.This thesis mainly studies the applicability of the equivalent model of the brazed aluminum honeycomb sandwich panel.Firstly,the three-point bending and plane compression tests of the sandwich panel were carried out.Secondly,the equivalent model was used to simulate the test process and compared with the refined finite element model to verify the calculation accuracy of the equivalent model.Finally,the equivalent method was used to establish the finite element of the vehicle structure.The model verifies the applicability of the equivalent model in the vehicle calibration calculation.Firstly,based on the theory of sandwich panels,the equivalent parameters are modified by considering the thickness of the solder between the cores on the basis of the traditional equivalent parameters.The accuracy of the equivalent model is compared with the refined finite element model,and the equivalent model established by the modified equivalent parameters has the highest calculation accuracy,which provides support for the application of the equivalent model later.Secondly,the three-point bending test of the sandwich panel was carried out,and the equivalent model and refined finite element model were used to calculate the equivalent parameters of the modified sandwich panel through the comparison of load-displacement curves,stiffness parameters and strength parameters.The established model has good accuracy in calculating the stiffness and strength performance of the sandwich panel.Thirdly,carry out the flat compression test study of the sandwich panel,respectively use the equivalent model and the refined finite element model to calculate,through the load-displacement curve,flat compression modulus and energy absorption comparison,it is concluded that the model established by using the equivalent parameters of the modified sandwich panel has good accuracy in calculating the flat compression performance of the sandwich panel.At the same time,the influence of the height of the sandwich panel,the angle of the cell,the side length of the cell and the thickness of the cell wall on the energy absorption performance of the sandwich panel is analyzed,and the average crushing stress,specific load,specific energy absorption and peak stress are approximately one-time or the quadratic function relationship,which providing a reference for the application design of sandwich panels in energy absorbing devices.Finally,using the equivalent parameters of the modified sandwich panel which has been verified by the three-point bending and flat compression load befoer,the finite element model of the vehicle head cover is established.Comparing calculations,it is found that the use of sandwich panel head cover can increase the local rigidity of the cab structure.The static strength of the honeycomb vehicle head cover is checked,and the applicability of the equivalent model in the static strength calculation is verified.Calculating the collision impact of the energy absorbing device and comparing with the refined finite element model to verify the accuracy of the equivalent model in the component-level flat pressure calculation.The equivalent model is used to calculate the deformation mode and energy situation of the energy absorbing device in the collision process,and the influence of the apparent density of the honeycomb on its energy absorption performance is analyzed,and the applicability of the equivalent model in the collision calculation is verified.