着陆冲击仿真月壤本构模型及有限元建模

摘要

为建立合理的月壤有限元模型用于着陆器着陆冲击动力学仿真分析,在对已知月壤的相关力学特性参数和试验数据进行分析推理的基础上,推断出月壤屈服面在低围压条件下可能会呈现出剪切膨胀特性,而在高围压条件下则可能会呈现出塑性压缩和应变硬化特性,因此定性地选择帽盖德鲁克-普拉格（Cap Drucker-Prager,CDP）模型作为月壤本构模型。模型的参数通过月壤或模拟月壤的试验数据定量地标定。对着陆器地面着陆冲击试验进行有限元建模和仿真分析,仿真结果表明：模型参数的标定方法是合理可行的;CDP模型可以准确模拟月壤在着陆冲击载荷下的动力学响应,可用于着陆冲击动力学仿真月壤有限元建模。对月壤模型参数进行了参数分析,并评估了月壤模型参数对着陆器着陆冲击性能的影响。%The purpose of this study is to construct finite element model of lunar soil for landing impact simulation of lunar lander.Based on the analysis of the known mechanical properties and tri-axial test data of lunar soil sample,it is found that lunar soil may exhibit shear-induced dilation at low confining pressure and plastic compression and strain hardening at high confining pressure.Cap Drucker-Prager（CDP） model is selected as the constitutive model of lunar soil according to the previous qualitative analysis,and the model parameters are calibrated quantitatively by test data of lunar soil or lunar soil stimulants.Finite element modeling and simulation analysis of lunar lander landing impact tests are conducted,the results indicate that calibration methods of model parameters are practical and reasonable.Dynamic response behaviors of lunar soil under landing impact condition can be accurately simulated by CDP model,and the model can be used for lunar soil finite element modeling.Parameters analysis of lunar soil model is conducted,and effects of parameters of lunar soil model on the landing performances of lunar lander are evaluated.