CRITICAL SAFETY FATIGUE CRACK SIZES FOR THE RD2 TYPE AXLE OF CHINESE RAILWAY FREIGHT CARS
The critical safety fatigue crack sizes are investigated for the RD2 type axle of Chinese railway freight cars. Attention is paid on the axle load relief grooves near the axle boxes, where more fatigue cracks were early appeared even result in at least six derailed accidents. Load history corresponding to the peak and valley points of wheel-rail contact forces, in which the wheel flat effect has been taken into account, is collected by vehicle dynamic simulation with on-line inspection. Different from the existent work, two axle crack/defect models, i.e. semi-elliptical and external circumferential cracks, were employed by the field inspections. Crack shape changes are taken into account in calculations of the crack growth driving stress intensity factors. The shear stress at the tip of semi-elliptical crack is also considered. Critical safety sizes for the two crack models are considered as the initial crack sizes, from which to axle fracture the residual life is equal to the overhaul inspection interval of axle. A step-by-step method is applied to determine the sizes. Results show that the external circumferential crack is more dangerous than the semi-elliptical crack. The critical sizes and the action of abolishing the load relief grooves have been applied in the field management. Two years practice has verified the availability.
Y. X. Zhao B. Yang M. F. Feng
Institute of Engineering Reliability and Safety, Traction Power State Key Laboratory, Southwest Jiao Institute of Engineering Reliability and Safety, Traction Power State Key Laboratory, Southwest Jiao
国际会议
第九届工程结构完整性国际会议(The Ninth International Conference on Engineering Structural Integrity Assessment)
北京
英文
2007-10-15（万方平台首次上网日期，不代表论文的发表时间）