Abstract: To study the dynamic response of a military cargo box under standard attitude drop,the performance evaluation of the packaging system is conducted through simulation analysis to provide data support for the structural optimization,and the simulation test is conducted to compare it with the hypothetical attitude drop. The difference of the response results is analyzed,and the importance of the standard attitude drop modeling in the simulation analysis is confirmed. Hypermesh and LS-Dyna integrated modeling idea is used to carry out finite element simulation analysis of different attitude drop conditions to obtain the stress cloud map of each part of the packaging system and the response acceleration curve of the built-in object. Under the standard attitude,the maximum stress of the system during the drop process of the face and edge does not exceed the yield strength of the corresponding material. During the angle drop process,the maximum stress of the box body is 76.654 MPa,which significantly exceeds the yield strength of the material. Compared with the standard attitude,the maximum stress,the peak response acceleration and the force response time of the system all have deviations in different degrees during the process of edge and angle drop under the hypothetical attitude. The structure of the cargo box will not be damaged when the face and edge drop test is carried out under the standard attitude,and there is a risk of damage when the angle drop test is carried out,so the structure needs to be optimized. In order to improve the accuracy of the drop simulation results of the packaging system,it is very important to build a finite element simulation model with a standard drop attitude.

Key words: finite element analysis, standard attitude, drop shock