Study On The Rigidity Of Structures Of Large - Caliber Gun Launching Process

Structure strength and stiffness issue of carriage body during launch is always a focus among large caliber artillery research, in particularly, the current development direction of artillery is giving consideration to high destructive power and mobility at the same time, its importance seems more outstanding. The research on this issue has an engineering value for guiding the carriage body structure design of howitzer, and a certen reference value for structure analysis and optimum design of general complicated mechanical system.In this thesis, based on nonlinear finite element theory and strength & stiffness theory, a large caliber vehicle-mounted howitzer has been taken as an object of study. Specific work of this thesis reads as follows:(1)Strength and stiffness theory of mechanical structure and its application in structure design had been stated. The application range and advantage between static and dynamic strength design had been compared. The methods of strength and stiffness analysis, the basic concepts of energy method and its application in stiffness analysis were also introduced in this t. All this works Laid a theoretical foundation for further research.(2)In order to find out an efficient and reasonable way to simulation the interactional relations between artillery structure and soil, the lumped parameter model based on Lysmer simplify analogy method was used to establish the vehicle-mounted howitzer dynamics nonlinear finite element model. On this basis,5 kinds of soil, whose stiffness and damping were different, had been selected to used in the FE model to acquire the influence laws of soil property on the artillery dynamic response. The results had a certain reference value in improving the calculation precision and efficient of the artillery dynamics finite element model.(3)Stiffness analysis and sensitive analysis of frame, top carriage, cradle carriage, etc, had been conducted. On this basis, carriage bodies with different stiffness were acquired by changing the parameters of high sensitive sub-structures. Used the vehicle-mounted howitzer dynamics nonlinear FE model, the artillery dynamic responses of different stiffness carriage bodies were acquired. The influence laws of single carriage body stiffness on other carriage bodies’ dynamic strain were acquired.(4)A parameterized vehicle-mounted howitzer dynamics nonlinear FE model was established. By combining the OLHD and Kriging technique, an approximate model was built, the NSGA-II was employed as the optimization method, and a Pareto optimal front was acquired. The result showed that, the mass and carriage body strain could be optimization at the same time by using the strength and stiffness optimum matching design method.