Study On The Rigid-Flexible Couple Launch Dynamics Of Truck-Mounted Guns

Based on multibody dynamics, finite element analysis, contact/impact theory and the correlational numerical methods, an approach toward the rigid-flexible couple launch dynamics was investigated for the trucked-mounted gun, which can provide theoretical foundation and design decision for overall design and structural design of such weapon systems.The solution accuracy of the contact problem depends upon the precision of the 3D model, so the components were modeled based on the NURBS theory. A subroutine about the Lankarani and Nikravesh contact force model was linked to extend the LMS/Motion's contact force model using the method of dynamic link library. In light of summation on the results from dynamic responses of impact/contact between typical parts, a procedure for dealing with impact/contact problem was presented for the trucked-mounted gun. The macro edited by VBScript was used to automatically set numerous models of contact/impact between balls for the traverse bearing. By taking the contact between ball and raceway, ball and adjacent ball, gear arc and main gear of the traversing mechanism, and the clearance between ball and raceway into consideration, the dynamic model of rigid bodies system was set up for the trucked-mounted gun. The effects of structural parameters of traverse bearing on muzzle disturbance and forces acted on parts were examined by using numerical computation.The flexible-body contact method is used to construct the coupling between the barrel and cradle bush. The barrel and the bush of cradle were meshed by CHEXA element manually and the master/slave nodes technique was used. Based on the Craig-Bampton method and the mode truncation technique, the main mode and the constraint mode of the barrel and bush were used to construct the flexible bodies by LMS/Motion. Via the model of contact between the flexible bodies, the effects of the barrel's flexibility and contact clearance on muzzle disturbance were analyzed for the trucked-mounted gun.Modeling of elastic and plastic deformation is conducted for soil. Soil, base plate, and spade were discretisized by solid and shell element, respectively. Drucker-Prager model was utilized for describing elasticity and plasticity of soil. The master/slave searching technique was used to get the relation between load and deformation. The least square fitting method was applied to attain the nonlinear stiffness curve, which was used in representing elasticity and plasticity of soil, and providing the soil model for multi-body dynamics analysis of the trucked-mounted gun. The plasticity of the two typical soil materials were numerically simulated, and their effects on muzzle disturbance were figured out.With comprehensive consideration on the multiple contacts in the traversing bearing, the contact between barrel and cradle bush, and the elasticity and plasticity of soil, a model of rigid-flexible couple launch dynamics was established for the trucked-mounted gun. The effects of the elasticity and plasticity of soil, the traversing bearing, and the flexibility of barrel on muzzle disturbance and forces acted on the key components were investigated by means of numerical method, and the simulated results were in excellent agreement with the test data.