变形摩擦元件对系统热弹性不稳定性的影响

建立了压力扰动与摩擦元件固连的反对称模态热弹性不稳定模型，应用该模型计算得到了判断摩擦系统热弹性不稳定性的临界速度，分析了弹性模量、泊松比等材料参数对摩擦系统热弹性稳定性的影响，并与Yi Yun-bo和赵家昕的有限元模型进行了对比分析.结果表明，变形摩擦元件对换挡过程影响较大，对蠕行工况影响较小.三种常用摩擦片中，纸基摩擦片TEI临界速度最高，热弹性稳定性最优，石棉摩擦片次之，铜基摩擦片TEI临界速度最小，热弹性稳定性最差；摩擦系统TEI临界速度随对偶钢片比热、导热系数和摩擦片热膨胀系数的增加而增加；随对偶钢片和摩擦钢片弹性模量与泊松比的增加而减小.对偶钢片材料参数不变的前提下，减小摩擦材料比热、泊松比、导热系数和弹性模量，同时增大热膨胀系数可提高摩擦系统的TEI临界速度、提高系统热弹性稳定性. 

Influence of Deformed Friction Components on the Thermoelastic Instability

The anti-symmetric thermoelastic instabilitymodel was developed to calculate the critical speed with the sliding condition of the perturbation fixed on friction components.The influence of material parameters such as elastic modulus and Poisson''s ratio on thermoelastic stability of the friction system was studied.The model was verified by the finite element solution of Yi Yun-bo and Zhao Jianxin.The results show that the deformed discs have great influence on the process of shifting,however little effect on the creeping condition.Among the three kinds of friction discs,paper-based friction discs have the best thermoelastic stability,while the Cu-based friction discs are the worst.The critical speed increases with the increase of the specific heat,thermal conductivity of steel discs and thermal expansion coefficient of friction discs.On the contrary,the critical speed decreases with the increase of the other material parameters.Under the premise that the parameters of the separator discs remain unchanged,the stability of the friction system can be improved by decreasing the specific heat,Poisson''s ratio,Young''s modulus and thermal conductivity,meanwhile increasing the coefficient of the thermal expansion.