Dynamics Design Of C-type Structural Vibration Reduction System Of Launch Vehicle

With the development of aerospace technology and the further demand of manned space exploration, the major-faring power in the world are all developing their own high-thrust launch vehicle. The exciting force caused by the high-thrust rocket engine will make the vibration problem of satellites and spacecrafts carried in the rocket more serious, and these vibration and shock will also do serious harm to the rocket, even destroy the rocket and result in launch failure. Meanwhile, with the increasing requirements of mechanical environment during the launch of rocket, the existing vibration reduction technology and vibration isolation technology can't satisfy the requirements. The research of reducing the vibration of launch vehicle affected by the rocket engine excitation is receiving more and more attention, and this issue is studied in this article. Based on the analysis of the causes, the corresponding vibration reduction scheme is proposed; the C-type structural Vibration Reduction System of Launch Vehicle is designed and analyzed through the finite element simulation.The vibration of launch vehicle during"Core-stage"flight is the most violent in the entire flight. One of the most important reasons is that the separation of booster and the burning of the fuel of the core of the first stage in the"First-stage"flight lead to the first order vertical frequency of launch vehicle close to and the excitation frequency of the rocket engine. Therefore, a kind of vibration reduction scheme reducing the stiffness of connection between the first stage and the second stage of launch vehicle in the"Core-stage"flight is proposed in this paper. The modular research method of vibration reduction system of launch vehicle, which utilizes the known dynamic parameters of the parts of launch vehicle to complete the design of dynamic parameters of the vibration reduction system of launch vehicle, is proposed according to this scheme. This method makes the design of vibration reduction system of launch vehicle have a better versatility and combination, greatly improves the design efficiency, shortens the design cycle, and saves the design cost.The C-type structural titanium alloy vibration reduction component is designed according to special properties of Ti, and its optimization theoretical geometry section is given through theoretical analysis. The finite element model of the component is established and its mechanical properties are analyzed. The finite element model of C-type Structural Vibration Reduction System of Launch Vehicle is established and the mechanical characteristic is analyzed. The finite element models of launch vehicle in different flight time and the finite element models of launch vehicle using the C-type Structural Vibration Reduction System at one point of"Core-stage"flight are established. According to the results of dynamical characteristic analysis, the first order vertical frequency of launch vehicle using the C-type Structural Vibration Reduction System moves away from the excitation frequency of the rocket engine, and the mechanical environment of launch vehicle and satellites and spacecrafts carried in the rocket in the"Core-stage"flight is effectively improved.