Study On Nonlinear Dynamics Simulation For Vehicle-Mounted Howitzers By FEM

This paper is concerned with the investigation on contact/impact occuring during the firing of a vehicle-mounted howitzer and its system dynamics by nonlinear finite element method (FEM), which can provide theoretical foundation and design decision for overall design and structural design of such weapon systems.Meshing technologies of finite elements with high precision for large-scale complicated structures are discussed and a modeling method of modularization and parameterization is presented. The whole system is composed of four modules, including recoil parts, cradle, and other components. Parameterization modeling with morphing technique is applied in each module, which makes modification of some model parameters easy and modeling efficiency high. Stiffness and strength of cradle, top carriage and auxiliary frame of the vehicle-mounted howitzer is studied by FEM. Vulnerable positions are found and improved to meet the design requirements.A contact/impact FE model of variable section rifled tube-projectile coupling system is constructed by use of mapped hexahedral elements. The band of the projectile is simulated with bilinear elastoplastic material model, together with the consideration of elastic and plastic deformation. The influence of coupling between rifling and projectile on muzzle disturbance and projectile motion in bore is investgated. Also dynamics response of both muzzle and projectile is examined upon considering the initial deflection due to gravity of tube.Drucker-Prager material model is employed to research the contact between spade and ground. Balanced master-slave search algorithm is used to model the contact/impact behavior between tube and cylinder-type cradle under different fitting tolerance, and an optimal tolerance is obtained. An FE model is constructed for the contact/impact between the main gear of elevating mechanism and cradle arc. The model reflecting contact between the upper and lower gear rings of cross-rolling bearing is developed. Based on the above contact dynamics analysis, the system nonlinear FE model is finally set up, and the numerical computation methodology for the nonlinear FEM is discussed, then the method of parallel calculation is used in dynamics simulation for the vehicle-mounted howitzer, in which the effect of soil performance and bearing condition on muzzle disturbance and projectile motion is taken into insight. The comparison between the simulated results and experiment data shows that the satisfied consistency is achieved.