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航天器结构的日益复杂和庞大为全系统级的动力学仿真带来了更大的困难和挑战,目前主要采用动态子结构法来提高分析求解效率,并解决不同设计部门之间的模型共享和技术保护问题。月球探测器软着陆阶段的冲击力学环境一般由加速度冲击响应谱描述,由于高阶振型对结构加速度响应的影响要比对位移响应的影响大得多,所以在小阻尼情况下,经典的基于模态的子结构方法在相同截断频率下对加速度响应的预测精度远低于位移响应。为解决这一问题,引进基于脉冲响应函数的时域子结构(IBS)方法,提出了一种适用于预测加速度响应的降阶形式的迭代求解格式。利用探测器着陆数值模拟试验中测得的缓冲机构作用力作为激励,分别采用固定界面模态综合(CB)法和IBS方法分析了月球探测器的加速度响应。数值算例表明,后者在计算精度和求解效率方面均高于前者,并说明基于脉冲响应函数的子结构方法适于对月球探测器加速度响应进行高精度快速预测。
The increasingly complex and huge spacecraft structure brings more difficulties and challenges to the whole system-level dynamics simulation. At present, the dynamic sub-structure method is mainly used to improve the efficiency of the analysis and solve the problem of model sharing between different design departments Technical protection issues. The impact mechanics environment of the lunar probe soft landing phase is generally described by the acceleration shock response spectrum. Because the influence of the higher modes on the structural acceleration response is much greater than that on the displacement response, in the case of small damping, the classical modal Substructure method predicts the acceleration response under the same cut-off frequency well below the displacement response. In order to solve this problem, an impulse response function-based time-domain substructure (IBS) method is introduced and an iterative solution scheme is proposed for the reduced order form of the predicted acceleration response. Using the buffer mechanism forces measured in the numerical simulations of the landing of the detector as stimuli, the acceleration responses of the lunar probe were analyzed using the fixed interface modal synthesis (CB) method and the IBS method respectively. Numerical examples show that the latter method is superior to the former in terms of both the computational accuracy and the solution efficiency, and shows that the substructure method based on the impulse response function is suitable for high accuracy and fast prediction of the lunar probe acceleration response.