蜂窝材料率相关本构模型及其在月球探测器中的应用研究

A rate-dependent constitutive model for honeycomb material and its application in a lunar lander

蜂窝材料是探测器缓冲装置中使用最多的缓冲介质之一,研究其力学特性对探测器缓冲器及上升器月面起飞稳定性设计具有重要意义。首先分析了蜂窝材料面内面外等效力学特性,在考虑蜂窝结构率相关特性的基础上,建立了蜂窝结构横观各向同性率相关本构模型;其次,基于有限元法编写了横观各向同性率相关本构模型用户子程序,并验证了其可靠性;最后,以四腿悬架式探测器为研究对象,研究了不同率敏感系数对探测器着陆过程的影响。结果表明:随着率相关系数的增加,缓冲器吸收的能量先增大再减小,当率相关系数为0.6时最大;探测器的最大冲击加速度一直增大,且当率相关系数较大时,最大冲击加速度增长速度较率相关系数较小时要大。

Honeycomb material is one of the most used buffer medium in the buffer device of a lunar lander, studying its mechanical properties is of significance for stability design of buffer devices of lunar lander and ascender＇s taking off from the moon＇s surface.Firstly,the in-plane and out-of-plane equivalent mechanical properties of honeycomb material were analyzed.and its rate-dependent transversely isotropic constitutive model was built considering the rate-dependent features of a honeycomb structure.Secondly,the user subroutine of the rate-dependent transversely isotropic constitutive model was written based on FEM,and its reliability was verified.Finally,taking a four-leg hanging rack lander as a study object,the influence of rate-dependent coefficients on its landing impact performance was studied.The results showed that with increase in a rate-dependent coefficient,the energy absorption of the buffer device increases firstly and then decreases,and reaches the maximum value when the coefficient is 0.6;the biggest impact acceleration of the lunar lander is increasing,and when the rate-dependent coefficient is larger,the growth rate of the biggest impact acceleration is bigger than that when the rate-dependent coefficient is smaller.