| When a tracked vehicle is walking or working,the vibration on the driving wheels is likely to cause it to disengage from the track and even break.If severe vibration occurs,it is further transmitted to the vehicle body,causing resonance of the entire vehicle,which seriously affects the service life of parts and the physical and mental health of the driver.Therefore,"a damping treatment" becomes a common method to cushion the vibration shock.However,the transition damping structure changes the "damping layer" to a "damping layer and transition layer" structure.During the vibration process,the transition layer works just like a better leverage.That could provide a good influence to the shear strain of the damping layer,thereby improving the energy consumption effect of the entire structure.In addition,the previous researches has found that the old damping structure only performs relatively well in a single working state,and the vibration reduction effect deteriorates.To this point,based on analyzing multiple working conditions of tracked vehicles,this text uses parametric modeling and adopts the methods of ANSYS and improved genetic algorithm,for having an optimized tubular transitional damping structure.The specific works are as follows:(1)Two kinds of driving wheel tubular transitional damping structures where the damping layer and the transition layer exchange positions are proposed.The structural parametric analysis model is established.Based on the modal strain energy method,the structural natural frequency and loss factor in the first three modes are analyzed.Therefore,the relatively good laying position of the damping layer and the transition layer in the structure is obtained.(2)Taking the bulldozer as an example,the transient dynamic analysis of the driving wheel tubular transitional damping structure is carried out under multiple working conditions,under its three typical working conditions.ANSYS first-order optimization is borrowed.The driving wheel tubular transitional damping structure satisfies the conditions that the total thickness is constant andthe transition layer and the damping layer do not exceed the allowable stress and strain.The energy loss ratio per unit period of the structure is used as the optimization goal.The design variables(base layer,constraint layer,transition layer,damping layer thickness and elastic modulus,loss factor of transition layer and damping layer material)are optimized.Through transient analysis under multiple working conditions,the maximum displacement,maximum stress and maximum strain of the damping layer and the transition layer before and after the optimization are compared.A more reasonable optimization result is obtained.(3)The niche-adaptive idea is borrowed.The mathematical model of optimization design used in the ANSYS first-order optimization is referred to.ANSYS and MATLAB are combined.The optimization of the driving wheel tubular transitional damping structure is optimized by the improved genetic algorithm.Through the comparison and analysis transient analysis under multiple working conditions,the optimized structure with more obvious vibration reduction effect is obtained.(4)Modal analysis,transient analysis,harmonic response analysis are applied.The performance of the structure before optimization,the structure after ANSYS optimization,and the structure after improved genetic algorithm optimization are analyzed.Further,the damping performance of each structure is discussed.The results show that when the transition layer is laid between the constraint layer and the damping layer,the vibration reduction effect of the structure is more significant.After two optimal designs under multiple working conditions,the driving wheel tubular transitional damping structures not only meet the stress and strain constraints,but also have a relatively large increase in energy loss ratio per unit period.This theoretical design and method can provide a certain reference for the vibration reduction design of various vehicle structures. |
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