Study On Nonlinear FEM Of Self-propelled Guns And Technology Of Visual Simulation

This paper focuses on launch dynamics of self-propelled gun with nonlinear Finite Element Methods and post-processing technology, based on "the Ninth National Five years project" of defense keystone research task of dynamic simulation technique study. The main results are concluded as followings: I ) A modeling method of modularization and parameterization is presented. The whole system is composed of six modules, each module is based on parameterization modeling, which makes modification easier and modeling efficient higher. II) A 3-D model and finite element model of a self-propelled gun is built. The intrinsic frequencies of all main assemblies and full gun are got, which are consistent with experiment data. III) The construction and solution of nonlinear finite element dynamics equations are analyzed, and the increment iteration method is used to solve them, in which Newton-Raphson or modified Newton-Raphson is adopted, also the stability of solution and convergence precision are discussed. IV) Revolute joint element, nonlinear spring-damper element, 3-D 5 points contact element are applied to simulate the revolute restriction between two caterpillar boards, suspension nonlinear vibration, contact between wheels and caterpillar boards, and contact between caterpillar boards and ground are considered respectively. Drucker-Prager material is employed to simulate reinforced concrete. V) The nonlinear dynamic response of vehicle, projectile, and gun barrel is derived by the nonlinear FEM. It is compared simulation results in which material nonlinearity of ground and contact nonlinearity between caterpillar boards and ground are considered with those without the former nonlinear factors. VI) The interface between multi-body simulation system and I-DEAS is developed, and the visual simulation of self-propelled gun is fulfilled based on the I-DEAS platform. Multi-media shows of self-propelled gun are accomplished including curve simulation, texturing, lighting technology voice effect, flame effect, etc. VII) Distributed real-time dynamics simulation system for virtual self-propelled gun, which is a solid basis for virtual-reality gun, is set up through LAN, based on TCP/IP protocol, OpenGL, Client/Server, Object Oriented, etc.