Sheet Metal Components A Number Of Stability Issues

In the view of the destorying of the equipment in port machine, two viewpoints take shape when the reason is analyzed, that is fatigue break and loss-in-stability break. What is the fatigue break? (this phenomenon is always happen in some place), the fatigue is that board appears apophysis and concave when the board is pressed. So that the board ability of bearing the weight of load will descend. Second, the board appear the flaw that the flaw extends in the some place of board, one reason is that the machine works too long, so the board ability of bearing the weight of load will decline. This thesis mainly studies the problem of local loss-in-stability, and discuss the problem of stability in the plate with symmetrical & dissymmetrical longitudinal stiffeners, and the effect in the stress of the weld, because the stress of the weld will change with the using of the equipment, there is also some analysis on this problem.The first chapter reviews the background of the research, first the critical stress of the problem of stability in two conditions of boundary is computed. Then compute the bend deflection equation of the plate which has the effect of initial curvature. In the last of this chapter discuss the effect of the critical stress when the plate was in the condition of corrosion and removal of weld.The second chapter discuss the stability of the plate with symmetrical & dissymmetrical longitudinal stiffeners. In this chapter, the equation which is how to compute the critical stress of plate with symmetrical & dissymmetrical longitudinal stiffeners is educed, that is the equation (2-5) (2-6). In the equation (2-5)&(2-6), we can use the coefficient and matrix to compute the value of k, and use this value can compute the critical stress.The third chapter and the forth chapter discuss two problems, the first is the analysis of infection under the shape wave, the second is the stability of the thin-wall structure. In the third chapter, I first gain the equation of the large deflection considering the plate that has original deflection, that is the equation of the compatibility and the bend deflection of the plate which has the effect of initial curvature. Then use the compatibility equation to solve the equation of membrane stress, and use Ritz method to solve the equation of the bend deflection of the plate which has the effect of initial curvature. In the forth chapter, gained two relations, that is the relation between in original deflection and the critical stress and the relation between the total deflection and the load. In the last of the forth chapter,discuss the thickness of the wall that has the affection on the stability of thin-wall structure, use the typical thin-wall structure-Cable Frame to analyse, and gain the critical thickness value of destroying between the strength and stability, and proof those conclusions from the test.The last chapter discuss the local loss-in-stability under the stress of the weld. First discuss the form and harm and control of the stress of the weld. And then gain the equation of the stress of the weld. At the last, compute the equation (5-14) of changing of the remainder stress of the weld, from this equation we can compute the fact remainder stress of the weld in some time.Shen.Honggao Directed by Ma.Jie...