The metallurgy crane, key and significant production equipment in metallurgy industry, mainly used for lifting high-temperature molten metal under adverse condition of high temperature and high dust for long time, is being highly concerned in its working reliability and safety. The metal structures of the Metallurgy crane are the welded structures, and the fatigue fracture failure is of the important failure mode. To guarantee the safe and reliable operation of the metallurgy crane for a long time, an accurate and effective method to monitor fatigue damage of the welding structures of metallurgy crane is urgently needed. Based on systematical analysis and research of the welding structures of the metallurgic crane, a kind of monitoring and forecasting method of fatigue damage in the hot spots of the welding structures of the metallurgic crane has been built. The basic process is as follows: Assure the stress hot spots of metal structure by building the metallurgy crane 3D model and finite element analysis; obtain the stress-time history curves in hot structure state by detecting the stress around with help of technology of Fiber Bragg Grating (FBG); The measured stress time history curves were processed by rain flow counting method, the calculation of the Miner linear fatigue cumulative damage theory, and the remaining life prediction; The fatigue damage of the hot spots is then calculated by Miner linear cumulative damage theory and residual life is afterwards predicted after processing stress-time history curve by the Rain-Flow Counting Method. In this paper, this method is used to calculate the fatigue damage and then predict residual life of welded structure of hot spots in an iron and steel enterprise 4S0T metallurgical crane, as a result, the crack-formation time of analysis and calculation results matches that in nature crack, showing the effectiveness and reliability of this method.
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