气囊着陆缓冲系统冲击动力学模型修正方法

Finite element model updating of airbag cushion landing system

针对气囊着陆缓冲系统的冲击动力学模型修正问题,首先建立了典型气囊着陆缓冲系统的冲击动力学仿真分析模型,考虑到结构动力学模型和气囊模型的相互独立性,提出对回收舱模型和气囊系统模型分别进行修正的分级修正思路;其次定义了关键点处冲击响应,解决了试验数据采样频率和试验触发不一致带来的计算结果与试验结果比较问题;就气囊着陆缓冲系统冲击动力学响应的典型特征,定义冲击响应置信因子评价计算结果与试验结果之间的吻合程度;以关键点冲击响应的试验数据与计算结果之间的误差范数作为修正目标函数,引入增广径向基函数构造修正变量关于修正目标的代理模型,将模型修正问题转换为优化问题进行求解;最后,通过典型气囊着陆缓冲系统冲击动力学试验和计算验证了所提方法的有效性。

This paper focuses on the finite element model updating of an airbag cushion landing system.First,a typical finite element model of an airbag cushion landing system is developed.Since the structure model and the airbag model is independent with each other,a systematic model updating strategy is proposed,and precisely for this reason the model updating of the recovery module structure and the airbag system are conducted individually.The impact responses at some key points are introduced to avoid the trouble caused by the difference between the sampling frequency and the trigger of the test and simulation.The confidence factor of the impact response is defined to evaluate the matching degree of the simulation results and testing results.The norm of the error between the testing data and the simulation results at the key points are defined as the updating objective,and the augmented radial basis functions are introduced to construct the agent model of the error norm.Since the minimum error norm will lead to ideal model parameters,model updating problem can be transformed into an optimization problem.The impact test and simulation of a typical airbag cushion landing system are conducted.The method presented in this paper is demonstrated through the comparison of the test results and the simulation results.