Reliability Assessment System Researching Of Gantry Crane Steel Structure Fatigue Life

Gantry crane, frequent lift heavy objects and load its own characteristics, during theservice, its structure is subjected to repeated alternating load, therefore fatigue brittle fractureis the main threat factor of structure security. The purpose of this paper，is researching thesuitable steel structure for the gantry crane, and construct the fatigue life prediction system,The system includes monitoring system, numerical simulation, Stress Spectrum Compilingand real time analysis. The main research of the paper included the following contents:First of all, through the ANSYS software, construct to structural entity parametericmodeling of gantry crane steel structure, to different size of gantry crane only need to inputspecific parameter, through the software make static analysis and dynamic analysis to thestructure, to obtain the stress time history data, determine the weak site of the gantry cranesteel structure, provide a basis for the arrangement of sensors, and calculate the initial stressof the structure on the zero state.Secondly, use the high durability, strong anti-jamming fiber grating sensor as the sourceof the health monitoring, to create a suitable structure of gantry crane monitoring system,through the fiber grating strain sensor to real-time monitor the stress changes at dangeroussection positions of the structure in different service conditions, get the stress time historydata of each measuring point.Once more, combined with the characteristics of portal crane, determine the suitablefatigue cumulative damage theory for the structure, and find the appropriate P-r-S-N curves toanalysis fatigue life reliability of weak parts.Finally, research the rain flow counting method thoroughly, through the monitoring systemto get the stress time history data and rain flow counting statistics, statistics the load spectrum.Selected four peak rain flow counting model, and apply Fortran language to programming, torealize the computerized of statistical.The system can real-time assess the life of dangerous section on gantry crane steelstructure, assess fatigue life on different confidence levels and different reliability, achievemore persuasive and valuable damage assessment results, the method can provide somereference effect for scientific management of gantry crane and similar structure fatigue lifeassessment.