高阶多边形车轮的瞬态磨耗行为分析

Analysis on transient wear of high-order polygonal wheels

采用ANSYS/LS-DYNA建立自由轮对运行于半径3500 m曲线轨道上的三维轮轨滚动接触有限元模型,于时域内模拟考虑轮对初始横移和侧滚角的高速曲线通过和瞬态滚滑行为,分析不同牵引系数下23阶实测车轮多边形对轮对曲线通过和车轮瞬态磨耗的影响。研究结果表明:车轮多边形会造成轮轨力、法/切向接触应力、摩擦功和磨耗深度等的周期性波动,最终造成非均匀磨耗;当速度为250 km/h和牵引系数为0.03时,峰谷幅值为0.128 mm的车轮多边形可使最大垂向轮轨力达113 kN(静态轮重的144%),摩擦功最大值可由平顺表面下的2 mJ增至2.3 mJ,相应波动幅值可达1.4 mJ;虽然一侧车轮多边形所激励的振动可以传递至另一侧,但对另一侧车轮多边形的发展不起主导作用;多边形造成的磨耗率峰值、谷值分别发生在多边形幅值的波峰、波谷附近,会抑制车轮多边形的进一步发展;牵引系数增大,会加剧车轮表面的平均磨耗和非均匀磨耗,加速车轮多边形的发展。

A three-dimensional wheel-rail rolling contact finite element(FE)model was developed by ANSYS/LSDYNA to simulate the high speed curving of a free wheelset on a curve of radius of 3500 m and the rolling-sliding behavior between wheel and rail in the time domain.The lateral shift and roll of the wheelset were set as initial conditions.The influence of measured 23-order polygons on the high speed curving and transient wear on the wheels at different traction coefficients was analyzed.The results show that the wheel polygons can lead to significant periodic variations of wheel and rail contact forces,contact stresses,friction work and worn depth,causing uneven wear.At 250 km/h and a traction coefficient of 0.03,due to the existence of the wheel polygons with a peak and valley amplitude of 0.128 mm,the maximum vertical wheel-rail force reaches 113 kN(144%of the static wheel load),the maximum frictional work reaches 2.3 mJ from 2.0 mJ on the even surfaces,and a fluctuation up to 1.4 mJ is present.Although the vibrations excited by the polygon on one side can be transferred to the other side,it does not play a dominant role in the development of the polygon on the other side.The peak wear rate and least wear rate occur near the geometric crest and valley of polygons respectively,prohibiting further development of the polygons.The increase of traction coefficient will increase the average wear and uneven wear of the wheel surface,accelerating the development of the wheel polygons.