Study On Launch Dynamics For Vehicle-mounted Weapon On Traveling

Vehicle-mounted weapon plays an important role on armament series of modern army due to its good maneuverability and protective ability.In order to make full use of its advantages,to improve operational efficiency and to ensure the survival probability,the ability of launch in traveling has become an important index to evaluate the tactical performance of vehicle-mounted weapon.To understand the dynamic response characteristics and force law during the process of launch in traveling,the methods of launch dynamics modeling,numerical simulation,and sensitivity analysis of structural nonlinear factors were investigated for vehicle-mounted weapon in traveling by means of multi-body system dynamics,finite element method and contact theory.Based on the reasonable simplification and hypothesis,the vehicle-mounted weapon are divided into multiple sub systems according to the actual function and movement of each part.The force characteristics of each sub system during the process of launch in traveling is analyzed.The dynamic equations of sub systems are derived by using Newton-Euler method.The component description method of space motion is described.The rigid flexible coupling dynamic equations of vehicle-mounted weapon is established.It provides a basis for establishing launch dynamics model of vehicle-mounted weapon in traveling.According to Chinese road roughness classification standard and the actual road conditions of battlefield.Harmonic superposition method which has good universality and high precision is adopted to achieve the two-dimensional surface model reconstruction.The coherent characteristics of road excitation is characterized by random phase difference of two wheels(track)random,and the road roughness model is extended to three-dimensional.Based on the periodogram method,verification results show that the power spectrum of road roughness model which established in this paper has high consistency with theoretical power spectrum.It can reflect the characteristics of random roughness with road surface level.The commoness and differences between two modeling methods of launch dynamics for weapon system in traveling and stopping are summed.Vehicle-mounted weapon launching dynamics modeling process is detailed.According to different structure features of a tank and a wheeled self-propelled anti-aircraft gun,topological analysis is carried out,respectively.The Mcpherson suspension model of front axle and hydro pneumatic suspension model of rear axle for wheeled chassis are established.Ftire model with multi-conditions applicability is introduced to the launch dynamics model of wheel self-propelled antiaircraft gun.C.oupling function between the tire and the road is described,and the conversion of the actual road roughness and effective road roughness is achieved.Based on professional tracked vehicle toolbox,the crawler chassis dynamics model which contains nonlinear stiffness suspension,contact between balance elbow and limiter is established.Both of two kinds of the vehicle-mounted weapon launch dynamics model are verified by the experiment data from the firing test.Elastic deformation of barrel is described by modal synthesis method.The rigid flexible coupling launch dynamic model is constructed for a wheeled self-propelled anti-aircraft gun and a tank,respectively.The influence of the elastic deformation on muzzle disturbance during process of launch in traveling is analyzed by numerical calculation.The rotating hinge dynamics modeling method is put forward for trunnion and bearing with small clearance.The contact algorithm in light of Lankarani&Nikravesh method is introduced into launch dynamics model,in which the nonlinear characteristics of the rotating hinge contact force acted on trunnion and bearing is taken into consideration.The effect of trunnion contact on muzzle disturbance,and load distributing of left and right trunnion are examined.Launch dynamics model containing large-scale contact/impact of ball race is constructed for a wheeled self-propelled anti-aircraft gun in traveling.The effect of race contact on vibration of muzzle is investigated by numerical computation.Forces acted on balls on different position during the process of launch in traveling are analyzed.The contact between tank gun barrel with radial clearance and sliding plates is modeled by the Rigid-To-Flex model.The effect of contact between barrel and sliding plates on muzzle disturbance is investigated by analysis of numerical calculation results,and forces acted on front and rear plate during the process of launch in traveling are analyzed.By comprehensive consideration of the proposed structural nonlinear factors,numerical simulation of launch dynamics is performed for vehicle-mounted weapon in traveling at different driving velocity and road level.The effects of elevation and azimuth,as well as overall structure parameters such as trunnion bearing clearance,clearance between barrel and sliding plates,and layout of front sliding plate on muzzle disturbance are analyzed.