内燃机曲轴轴系弯扭耦合非线性振动响应

建立了内燃机曲轴轴系弯扭耦合运动微分方程，模型中考虑了轴系变惯量、质量偏心和非线性干摩擦阻尼力等因素.采用数值积分法研究了质量偏心和转速对系统非线性动力学响应的影响；将系统微分方程组转化为非线性代数方程组，运用谐波平衡法获得了系统幅频特性.结果表明，谐波平衡法与数值积分法得到的结果吻合较好；气缸与活塞间阻尼会对系统响应振幅产生明显抑制作用；减小曲轴轴系偏心量可以有效地提高曲轴系统运动稳定性.

Response of Nonlinear Bending Torsional Coupling Vibration of the Combustion Engine Crankshaft System

The bending torsional coupling dynamic model of the crankshaft system in combustion engine was presented by considering varied inertia， mass eccentricity and nonlinear friction damping force. Numerical integration methods were adopted to analyze the effects of the mass eccentricity and rotate speed on the dynamic performance， and the characteristics of amplitude frequency responses were obtained based on the harmonic balance method. It is shown that the harmonic balance method coincides well with the numerical method. The damping between the cylinder and piston can produce significant inhibition of system response amplitude. The motion stability can be effectively improved by reducing the eccentric of crankshaft system.