Strength Analysis And Optimal Design Of Articulated Mechanism For Articulated Tracked Vehicle

Articulated tracked vehicle has the advantages of flexible mobility and strong passage capacity.It can run in all kinds of extreme conditions,and implement rescue and transportation works quickly and precisely.Articulated tracked vehicle's through performance is strong because of its front and rear body connected by an articulated mechanism.This mechanism enables the front and rear body to achieve relative steering,pitch and twist motion.And the steering and pitching motion are controllable.When the vehicle is traveling on uneven terrain,the bodies can be adjusted with the change of terrain.This can help the track maintain contact with the ground as far as possible,then the vehicle get a higher capacity.Therefore,it is necessary to study the articulated mechanism of articulated tracked vehicle.In this paper,we present the existing articulated mechanism,and compare the advantages and disadvantages of each articulated mechanism.According to the actual motion of this articulated tracked vehicle,the proper articulated mechanism is designed and selected.This mechanism enables the front and rear body to achieve relative steering,pitch and twist motion.On the basis of studying the mechanism of interaction between tracks and soil,the steering model of articulated tracked vehicle is established.Thus,the theoretical formulas for calculating the shear resistance and the steering resistance moment of track are derived.So it provide theoretical basis for solving the mechanical problems between track and clay pavement in the steering process of the articulated tracked vehicle.Finally,through the analysis of the geometric parameters the force relationship of the articulated mechanism,the formula for calculating the force of pitching cylinder is obtained.It can provide the basis for the structural design,parameter selection of articulated mechanism and the design and control of the hydraulic system.Based on the analysis of the kinematic characteristics of the articulated mechanism of articulated tracked vehicle,the unified multi objective function method is used to establish the optimization model of the hinge position of the articulated mechanism based on genetic algorithm.Through the completion of entire optimization process,stroke difference and torque difference between left and right cylinders are greatly reduced compared with the original mechanism.Therefore,the pressure fluctuation and unsteady flow of the hydraulic oil will decrease and the vibration,shock and energy loss in the process of steering will also reduce.The steering performance of the vehicle is improved after optimization.The finite element model of the hinge mechanism is established by using Hyper Mesh software.And the model is simplified in accordance with the practical situation.The assembly model is transformed into a finite element information file which can be identified by ANSYS software.The constraints and loads are applied to the finite element model in ANSYS software.The selection calculation conditions are steering at the time of 0 degrees,steering at the time of 35 degrees,pitching conditions,and horizontal conditions.According to the calculation results,Amendments and improvements are proposed.Finally,using the Opti Struct module of Hyper Works software to optimize the articulated mechanism,the topology optimization is carried out.Take upper hinged support as an example,establish its optimization model.According to the actual load conditions,the boundary conditions are determined.By define the corresponding design variables,constraints and objective functions and combining with the actual processing,the final improvement model is obtained.Comparing the performance of before optimization with that of after optimization,the optimized model's weight was lighter.The optimization scheme is feasible.