A Study of Internal Stress Concentration Zones in Load Carrying Part of Passenger Wagon

摘要

At present, conventional non destructive testing methods are used in Mongolian Railways for satisfy safety requirements of railroad transport. The NDT usage is limited by controlling integrity of moving part, detecting of internal and external defects. These conventional NDT methods are unable to detect stress concentration zones, which can be create in working part during service. For example, when wagon part metal exerting the sudden load such as braking then part material can fracture leading to accident. Recently developed new NDT method named Metal Magnetic Memory (MMM) method can detect stress concentration zones by detecting of self-magnetic-leakage field (SMLF) distribution on component's surfaces. It gives quantitative estimation parameter named magnetic index m for material limiting condition, which used for life assessment of the part tested. In this work stress concentration zones in load carrying part of wagon were measured by specified instrument of MMM. Analyzing of measured data with using specific software developed for determination of internal stress concentration zones and estimation of residual life of tested component. In result of this experiment the residual life time of the tested 31 years old component was determined as 8.2 years.