Metal Structures Of Cranes Stiffening Sheet Carrying Capacity Of Experimental Study And Simulation Analysis

The modern trend for the development of crane is maximization and high-efficiently. On the other hand, limited by the port condition and manufacturing cost, while the weight of crane is high, the demand of its own weight control demand is also higher to higher.At present, the external dimension of box beam structure of the crane is larger and larger, some even reaches 3600mm. so "thin wall " becomes the important characteristic of metal structure of the crane. This characteristic makes local stability bearing capacity of the structure drop suddenly. When the stability bearing capacity are smaller than a certain external load, the structure will lost stability in part and withdrawn the load finally, lead to destruction such as collapsing wholly or breaking. In recent years, a series of accidents happened again and again. It also shows this problem. Most accidents happened under the state of the normal task. In the face of these accident, setting up one intact security evaluation system to guide equipment management of enterprise become an urgent problem to be solved.Our seminar has gained some theory and experience accumulation on the security evaluation system of the metal structure (seminar has already finished Shanghai State Education Commission fund project: the invalidation studies of the container metal structure based on fracture theory, the serial number of the project: 02JK05; the crack explanding law of large-scale mechanical structure's panel in common use, the serial number: 97JG5055). The seminar has already set up more intact system in the evaluation of fatigue and rupture, but still stay in aspect of quoting criterion in local stability research of the component, need simulating and testing to see its invalid mechanism. So, this text has carried on experimental study and the finite element simulating on the question of stability of the stiffened panel with initial defect, seek how to apply the theory of the stiffened panel with initial defect to project reality.This paper uses the pressed flange plate of the crane metalstructure's box section as the research object. It is simplified as a four-side simple support stiffened panel. The means of combining loading test and finite element analysis has been used to do some beneficial exploration on stability mechanism of the panel.We have done some loading testing on the panel with different initial deflections and different stiffener. In the tests, we measured the membrane stress and the crooked stress in the key position of the panels and gained the waveform's distributing of the panels before and after loading. Certain perceptual knowledge to critical load, limit load, waveforms redistributing, which all belong to the stiffened panel with initial defects, have been got. The characteristic distributed for the membrane stress and crooked stress, has proved the bucking course of the panel is non-linear.In the analysis of the finite element, we simulated the real panel and condition of restraining which are in the loading test, utilize the non-linear analysis flat ( eigenvalue of bucking analysis, flexibility plasticity analysis) which is in ANSYS, the large-scale finite element analysis software, proved the reliability of the calculating value on theory of the ideal stiffened panel's the critical load of bucking, receive the relation curve between initial deflection and critical load of bucking, and the influence curve between scale of width and thickness and limit load when the panel has certain initial deflection. Compare it with the result of the test and get the conversion coefficient of finite element analysis with actual limit load. The cloud chart of the panel's stress distributing has also been observed, which proved the exactness of the conclusion in test.