内燃机曲轴的弯扭耦合非线性振动分析

Analysis of Non-linear Coupled Bending-torsional Vibration of Internal-combustion Engine Crankshaft

以内燃机曲轴单位曲柄为研究对象,着重考虑刚度不对称和质量偏心的影响,建立了系统的非线性运动微分方程,利用数值方法对曲轴的非线性动力学特性进行了仿真.结果表明:随着质量偏心的增加,弯扭耦合区的范围增大,系统运动由周期运动变为概周期运动;随着刚度不对称系数的增加,系统出现环面倍化分岔,并转变为混沌运动;随着扭转刚度的增加,系统的运动趋于稳定.

Taking unit crank of internal-combustion engine crankshaft as study object,the nonlinear differential equation of bending-torsional vibration of crankshaft system is built, emphasizing the effects of stiffness asymmetry and mass eccentricity. The dynamic charaeteristies of crankshaft system are analyzed by using numerical method. The results show that the coupled bending-torsional vibration range increases and the motion changes from periodic motion to quasi-periodic motion as the mass eccentricity rises; with the increase of stiffness asymmetry coefficient, it can generate torus-doubling bifurcation and then changes into chaotic motion;the motion of system tends to be stable with the increase of torsinal stiffness.