柴油机球墨铸铁飞轮应力与断裂损伤失效分析

Stress and fracture damage analysis of nodular iron flywheel for diesel engine

球墨铸铁飞轮是柴油机中结构形状相对简单但起重要作用的零件之一。对于圆盘状球墨铸铁飞轮,其结构破坏行为往往与飞轮在高速旋转时所引起的包含径向、轴向及环向等复杂的三维应力状态有关。此外,还与其表面摩擦损伤有关。为了分析飞轮高速旋转时的复杂应力状态与其断裂损伤失效之间的关系,用有限元方法分析了球墨铸铁飞轮在高速旋转时径向应力、轴向应力及环向应力的分布情况,预测飞轮的极限转速及断裂损伤形式,同时用实验的方法进行验证分析,实验所得结果与有限元分析结果具有很好的一致性。该方法对飞轮失效分析及飞轮结构优化设计具有重要的理论指导意义。

Nodular iron flywheel is one of the parts which have relatively simple structure but play an important role in diesel engine. In the case of disc-shaped nodular iron flywheels, the structural damage behavior is strongly influenced by complex three-dimensional stress states in the flywheel structure. The complex three-dimensional stress states in combination with the ordinary radial, axial and tangential stresses are caused by high speed rotating of the flywheel. In addition, the structural damage behavior of the flywheel is also related to its surface fatigue wear. In order to analyze the relationship between the complex three-dimensional stress and failure of the high-speed rotating flywheel, the stress distributions of radial stress, axial stress and tangential stress were given by finite element method, the limit speed of the flywheel and its fracture damage forms were predicted; In the mean time, experimental analysis was carried out for the fracture and damage of the flywheel. The experimental results are in agreement with the finite element analysis results. Such method of combining finite element with experiment analysis is of important guiding significance for the failure analysis and structural optimization design of the flywheel.