Dynamic Analysis And Computation For Certain Missile

Based on the experimental response data of acceleration and the practical missile structure and material parameters, the natural frequency of transverse vibration, the response and the deflection angle of the missile body are all computed by employing the theoretical and finite elemental methods. And the dimension of the system is reduced. By comparing the computed results with the experimental results.For the theoretical computation, the missile body is simplified as a cascade beam with interior structural beams and lumped mass according to the practical structure of the missile. And the key to solve the cascade beam problem is to build up the transfer matrix by the continuous conditions. The differential equations of vibration are built up for each sub-beam and are solved through the Laplace transform. By means of the continuous conditions of two adjacent sub-beams, the transfer matrix can be established. Then the whole transfer matrix between the first and the last sub-beam is built up with the transfer matrices between the adjacent sub-beams. Finally, the natural frequency of the missile body is calculated using the boundary conditions of the missile body.As to the finite element computation, the software-NASTRAN is employed. Firstly, the analytical model is built up according to the missile structure. Then the natural frequency of the missile body can be computed by compartmentalizing the model and defining the material parameters and boundary. Finally, the acceleration responses obtained by the finite element method are compared with the corresponding experimental results, and the feasibility of finite element is verified by calculating and analyzing the errors.During calculating the deflection angel of vibration of the missile body, the deflection angel bout the Y and Z axes by a plane determined by three arbitrary points on the missile is computed. Under several assumptions and programming with MATLAB, the deflection angles are calculated with the experimental acceleration data and displacement results acquired from the finite element method and the results obtained by the two methods are compared with each other. As for reducing the system's dimension, for the cases of one input with one output and two inputs with one output, the frequency response function is obtained with the Fourier transform and the optimum order of the system is obtained.In this paper, the dynamical problems of the missile body are calculated and analyzed. The results show that the vibration experiment for the missile is feasible and the exactness and validity of the computation methods and programs in the paper are also verified.