有效载荷基频降低对火箭动特性的影响

为了分析有效载荷基频降低对火箭动特性的影响规律,采用纵横扭一体化梁模型与耦合质量方法模拟箭体承力结构与液体推进剂,使用NASTRAN中的RBE2单元模拟芯级与助推器连接接头.通过修改有效载荷有限元模型以得到不同的有效载荷基频,选取飞行过程中的四个典型秒状态,计算三种不同有效载荷基频下全箭的前九阶固有振动频率.结果表明：纵横扭一体化梁模型在进行全箭动特性分析时模型简单,结果满足要求,可用于设计初期的模态分析;同时,分析得到基频降低对全箭动特性的影响规律,给卫星设计人员提供了相关依据.

Effects of Payload＇s Base Frequency Reduction on Dynamic Characteristics of Rocket

In order to analyze the effects of payload＇ s base frequency reduction on dynamic characteristics of rocket, the longitudinal-lateral torsional integrated beam model and coupled mass method are used to simulate load bearing structure of rocket and liquid propellant, and the RBE2 element in NASTRAN is also used to simu- late the joints between the core and the booster of launch vehicle. Different payload＇s base frequency can be obtained by modifying the finite element model of payload. The author chooses four typical second states in the process of flying, and obtains the first nine natural frequency of the rocket in three different payload＇s base fre quency. Results show that the integrated beam model is very simple and practical in analyzing the dynamic characteristics of rocket, and the results can meet the requirements. The model can be used for modal analysis at the early stage of design. At the same time, the effects of payload＇s base frequency reduction on dynamic characteristics of rocket can be obtained by analyzing the natural frequency data. These conclusions can provide some re lated basis for the design of rocket.