Reliability Study On Overhead Crane Structure With Multiple Cracks

With the continuous progress of science and technology of modern machinery industry in China and the continuous development of the industry scale,the application of overhead crane is more and more extensive,and ensuring the reliability of its operation is becoming more and more important.The reliability of the bridge structure,the main load-bearing component of the overhead crane,directly determines whether the overhead crane can work normally.In order to ensure the safe and effective operation of overhead crane,it is necessary to study the reliability of its bridge structure.There are a lot of components such as large transverse bulkhead,small transverse bulkhead and longitudinal stiffener in the thin plate welded box structure of large span overhead crane and the structure is relatively complex.In the case of repeated loading,the thin-plate-box beam is prone to stress concentration and crack failure.The failure of any part or component of crane box girder with complex configuration may lay hidden trouble for the safe operation of overhead crane.Therefore,it is very important to study the reliability of complex bridge structure of overhead crane under the condition of multiple crack faults.In this paper,the reliability of the overhead crane is studied by considering the multi-crack fault condition which widely exists in the actual overhead crane structure.In this paper,the overhead crane as the research object,through the finite element modeling of mechanical performance analysis,and combined with the relevant structural reliability theory,the bridge in the initial structure and multi-crack structure reliability research.Firstly,the finite element model of the bridge crane structure is established,and the mechanical properties are calculated when the full load crane is located in the unfavorable position of the main girder,and the maximum stress and location of the bridge structure are calibrated.Secondly,combined with the theory of structural reliability evaluation,a reliability analysis method of the partition lattice of overhead crane structure is proposed,and the reliability analysis of the initial structure of the overhead crane is carried out by using this method.Then,the reliability of the bridge structure of the overhead crane is studied when cracks occur in the failure prone parts of the overhead crane with multiple stress concentration.Finally,through the analysis and comparison of the reliability of the initial bridge structure and the multi-crack fault bridge structure,some measures to improve the reliability of the bridge structure are put forward.