Mechanical Analysis Of The Launching Force Of The Terminal Guided Gun And The Optimization Of The Protective Structure Of The Test

Study of terminal guided projectile launching dynamics is an important process for analyzing the reliability and safety of the terminal guided projectile, and it is of great significant to the design of terminal guided projectile. Besides, analysis of projectile launching process is also important for the study of interior ballistics process and the design of guns. The projectile launching process is an extremely complex physical and chemical process with characteristics of strong shock, high transience and high nonlineariry. In this thesis, launching process of terminal guided projectile was studied by nonlinear finite element analysis and numerical simulation, and the technology of cushion and protection for projectile-borne testing equipment was investigated for background of the test problem of in-bore projectile.The components and structural characteristics of the terminal guided projectile launching system were analyzed. The structure characteristics of sliding band were depicted, including obturation, centering, and decreasing spin, et al. The force features of terminal guided projectile in engraving process and in-bore process were investigated, as well as characteristics and calculations of the gunpowder gas pressure, radial pressure of the rotating band, non-homogeneity force, friction, lateral guiding force generated by the rifles were presented.The gun barrel, the sliding band and the terminal guided projectile were meshed by the reduced integration isoparametric hexahedron element, shell element and other types of element, respectively. The Johnson-Cook constitutive model and arbitrary Lagrangian-Eulerian method were employed for simulation the large deformation of sliding band. The penalty function method was used to simulate the contact between the sliding band, the terminal guided projectile and the gun barrel. The finite element model of terminal guided projectile launching system was established and explicit numerical integration algorithm was used for numerical simulation of the terminal guided projectile launching process. The formation process of the rotating band grooves, the elastic-plastic strain of the rotating band, and the movement law of the projectile were analyzed. By the comparative analysis of results reported in open literatures, the correctness of the simulation models and results were verified.The influence factors on terminal guided projectile launching process were researched. Different finite element models of terminal guided projectile launching system were established from the aspects of different friction coefficients of band and the band groove, different length of the band as well as band radial interference. Rotational speed of projectile was calculated by the proposed model, and were compared with the result calculated by the formula for calculating the spin speed of sliding band. The influence of structure parameters on decreasing spin of terminal guided projectile was investigated, and the design suggestions of the band structure of the terminal guided projectile were summarized. Different finite element models of terminal guided projectile launching system were established from the aspects of different gap between the projectile and gun, and the eccentricity of the projectile, and the projectile overload in bore was calculated. The structure parameters on overload of terminal guided projectile in-bore was analyzed, and the suggestions for improving structural design of the terminal guided projectile were presented.For the testing problem of in-bore projectile, the cushion and protection technology for the circuit module of projectile-borne testing equipment was studied. The damage mechanism of the circuit module of projectile-borne testing equipment were analyzed, and the cushioning mechanism was discussed, and a circuit module composite buffer protection structure was proposed. Base on iSIGHT and ABAQUS, an optimal design of the buffer protection structure was carried out by using multi-island genetic algorithm and sequential quadratic programming method. The proposed optimal design method can provide some reference for buffer and protection structure of this kind of system.