500吨级液氧煤油发动机结构动态特性

为获得我国载人登月运载系统用500吨级液氧煤油发动机结构动态特性,采用有限元方法对发动机整机结构进行了模态计算分析,并对影响结构动态特性的相关因素进行了分析,获得了发动机的模态参数以及优化结构低频特性的有效途径。针对该发动机零部组件多、结构复杂度高的特点,采用子结构有限元模型组装并结合部分组件试验的方式建立了整机结构的有限元仿真模型。计算结果表明,在目前设计状态下,发动机的首阶模态频率约为8.8 Hz。进一步优化表明,通过增大工艺拉杆倾角,可显著提升伺服回路在相应方向上的横向刚度,从而使该方向上的模态频率得到大幅提升。

Research on structural dynamic characteristics of the 500-ton LOX/kerosene rocket engine

To obtain the structural dynamic characteristics of the 500-ton LOX/kerosene rocket engine which is planed for the manned lunar project,the finite element method was used for modal analysis of the whole structure of the engine.In addition,the factors which may affect the dynamic characteristics were analyzed,thus the modal parameters as well as the approach to optimize the low frequency dynamic characteristics were obtained.In view of large number of subassemblies and complicated structure of the engine,the finite element model of the engine was established by assemble the finite element model of the substructures in combination with some modal test of subassembly.The results show that the first modal frequency of the engine in current state is 8.8 Hz.The optimized results show that the horizontal stiffness in the corresponding direction of the servo loop structure can be enhanced dramatically,which makes the corresponding modal frequency of the engine improved significantly by increasing the dip angle of the pull rod.