扣件刚度非线性对波磨区轮轨瞬态滚动接触行为的影响

Influence of Fastener Stiffness Nonlinearity on Wheel–Rail Transient Rolling Contact Behavior in Corrugated Area

WJ-8型扣件橡胶垫板刚度在长期服役过程中表现出非线性特征,静刚度随荷载增加而降低,为提高三维瞬态滚动接触有限元模型计算精确性,本文以LMA踏面车轮及CHN60型钢轨为基础,基于显式积分算法,将以往研究中线弹性扣件转化为非线性扣件,建立考虑扣件刚度非线性特征的三维轮轨瞬态滚动接触有限元模型,研究刚度非线性对车轮与钢轨波磨间高频动态响应及瞬态接触行为的影响,并重点分析了波磨工况下时频域内轮轨接触力、轴箱加速度的变化信息.结果表明:扣件非线性对轮轨接触力变化影响明显,主要表现为车轮行驶至扣件前端时强振动导致橡胶垫板表现为柔软特性使轮轨接触力减小,车轮行驶至扣件上方时在轴重作用下振动减弱表现为刚硬特性使轮轨接触力增大,轮轨力变化差异最大达到13.1%.

The stiffness of the rubber pad of the WJ-8 fastener exhibits nonlinear characteristics during long-term service,and the static stiffness decreases with the increase in the load.In order to improve the calculation accuracy of the three-dimensional transient rolling contact finite element model,the LMA tread wheel and CHN60 rail were used.Based on the explicit integration algorithm,the linear elastic fasteners in the previous research were transformed into nonlinear fasteners to establish a three-dimensional wheel–rail transient rolling contact finite element model considering the nonlinear characteristics of fastener stiffness.The influence of stiffness nonlinearity on the high-frequency dynamic response and transient contact behavior between wheel and rail corrugation was studied,and the change of wheel–rail contact force and axle box acceleration in the time-frequency domain under corrugation conditions was analyzed.The results show that the nonlinearity of the fastener has an obvious effect on the change of the wheel–rail contact force.The main manifestation is that when the wheel travels to the front end of the fastener,the strong vibration makes the rubber pad soft,which reduces the contact force of the wheel and rail.In addition,when the wheel travels above the fastener,the vibration is weakened under the action of the axle load;the stiffness characteristic increases the wheel-rail contact force,and the difference between the wheel–rail force changes is up to 13.1%.