Study On Remanufacturing Parts Damage Monitoring And Life Prediction Based On Multimedia Mix

The purpose of this study lies in solving the online monitoring and fatigue life prediction of remanufactured crankshaft. It can provide with service that could guarantee security for manufactured crankshafts and reduce the property loss and waste of resources caused by crankshaft failure. The significance of this study is to evaluate the fatigue performance of remanufactured crankshaft with low cost, as well as to meet the requirements of remanufacturing engineering, which means saving energy and reducing costs. In view of high costs of time and money the traditional method, how to ensure the reliability, while reducing costs, shortening testing cycle is the focus of this study.The remanufactured samples used for bending fatigue test are made of the same matrix material, coating material and spraying process. For remanufactured the evaluation of fatigue performance of specimens, we need to warn fatigue failure timely. The fatigue strength and fatigue life and other parameters should also be determined. A single test cannot meet the all the mentioned requirements. Therefore, through resistance meter, infrared imaging and acoustic emission device real-time monitoring, this paper can advance the warning of fatigue damage. This study could also predict the fatigue limit and service life. Eventually, the three devices collected the resistance, temperature and acoustic emission signal during fatigue tests, and realized the online monitoring and fatigue life prediction. Final results are as follows:(1)There is a good correspondence between resistance, infrared, acoustic emission and the fatigue process. Resistance and acoustic emission signal is relatively stable in the process of tests, and mutations in the signal appear before fatigue failure. Temperature achieved by infrared thermal imager present three phases: initial risen, stable phase and temperature rise suddenly. The damage cumulative, energy dissipation and the change of the stress wave can be expressed by above three signals, they all suitable for the on-line monitoring of fatigue failure.(2)Three kinds of signal are combined to warn fatigue failure in this study and it works well. Fatigue failure can be warned in the early stage by acoustic emission. Several mutations signal appears hundreds of seconds before fatigue failure.(3) Infrared data is analyzed by both Risitano method and Luong method to predict fatigue limit. The analysis found that, Risitano method is more suitable for small changes datas, while the Luong method is applied to a big change, and the fatigue limit of sample determined by those two methods is between 200 MPa and 250 MPa.(4) The temperature acquired from infrared and resistance analyzed by damage cumulative and energy dissipation respectively. Fatigue life of both new specimens and remanufactured specimens are predicted. After the comparison with test S-N curve, we know this prediction is accurate, and S-N curve of remanufactured specimens is got quickly with low cost.(5) Fatigue life before and after spraying remanufacturing of specimens is compared in this work, it can be found that, when stress is larger, fatigue life value of them is close, while when the stress is small, the gap of fatigue life is large. This conclusion is useful to the safety service of remanufactured parts.