巡天任务复杂工况下超静平台作动器疲劳寿命评估

Fatigue Life Evaluation of Ultra-quiet Platform Actuator for Complex Astronomy Survey Missions

为研究超静平台作动器的疲劳寿命特性,以其在轨执行巡天任务时的复杂工况分析为出发点,开展了典型工况下的超静平台物理试验,获取作动器实测载荷数据;采用有限元仿真模型进行疲劳损伤系数计算,根据“累积损伤-临界损伤”干涉模型进行累积损伤建模,推导了基于损伤系数外推的作动器概率疲劳寿命解析模型;利用最大损伤系数对应工况进行试验载荷谱设计,开展作动器疲劳寿命试验获取疲劳寿命分布,结合模型计算给出超静平台上不同损伤系数对应作动器的疲劳寿命评估结果。结果表明,运用建立的方法及模型,能够结合超静平台巡天任务工况,利用基于载荷谱编制的疲劳寿命试验结果,计算出平台上各作动器可靠度随在轨时间变化规律及概率疲劳寿命,可为超静平台作动器等一类在轨工况及载荷谱复杂、多样的空间运动机构提供一种真实有效的寿命评估技术途径。

In order to study the fatigue life characteristics of the ultra-quiet platform actuator,starting from the analysis of the complex on-orbit survey task conditions,a physical simulation test of the platform is carried out to obtain the actual load spectrum of the actuator under typical working conditions.The finite element simulation model is used to calculate the fatigue damage coefficient,and the cumulative damage model is established according to the“cumulative damage-critical damage”interference model,and the analytical model of the probabilistic fatigue life of the actuators is deduced based on the damage coefficient extrapolation.The test load spectrum is designed based on the maximum damage coefficient,and the fatigue life test of the actuator is carried out.Based on the correctness verification of the model,the fatigue life evaluation results of the actuators are given.The results show that the established method and model can be combined with the ultra-quiet platform astronomy survey task conditions,and the fatigue life test results based on the load spectrum can be used to calculate the reliability variation of each actuator on the platform with the on-orbit time and the probabilistic fatigue life,which can provide a real and effective life evaluation method for space motion mechanisms with complex load spectrum and on-orbit working conditions.