Yield-Line Theory Application And Studying Of The Plate In Plastic Limit State

With the continuous development of society, thin-slab structure due to its own structure advantages is used more and more extensive in all kinds of engineering structure. The final strength problem of plate structure under the role of limit load is prominent increasingly. Therefore, researching overall mechanics behavior and limit strength of plate structure under the role of limit load becomes a hotspot research subject in structural mechanics field recently.First of all, this paper systematically elaborates the basical comcept and theories of board structure. And it introduces the bassical theory and differential equation of the elastic lamella bending problem in detail. And it forces the Winkler foundation plate analysis method to establish the Winkler foundation plate mathematical model. Simultaneously it has carried on the analysis to the boundary condition and the component of stress. In the next place, this paper studied the failure criterion for the thin plastic bonding. And it introduces the plastic yield criterion and the plastic constitutive model in detail. Based on the Mises yield criterion, this paper establishes the quite stress expression with the displacement for the fourth strength theory. And establishes the strength criterion of lamella bending plastic limit analysis. And espounds the calculation principle of the plastic yield line method.Establishes a new computation module of plastic yield line. Once again, this paper carries on plastic limit analysis to lamella bending ultimate load with plastic yield line theory. Taking the force situation of the rectangular lamella and polygon plate under the simple support and clamped boundary conditions as example, this paper solves the ultimate load with the method of plastic yield line. In the end, this paper derived a general expression of the equivalent stress for the limit load when the simple supported plate is under the concentrated load and the boundary for arbitrary shapes.Applying the yield-line theory to analyze the plate bending problem and combining strength criterion, we can establish the limit load expression based on allowable stress. By analysis, we get the result that the plastic hinge line position of the structure and the characteristics of breakage and the load of the structure could beared and the distribution of internal force when a structure gets to the limit state, and so on. It has formed a method of using plastic limit theory to analyze the structure plastic failure in load. The calculation process of the method does not involve the structure stress and strain of section; it finds the final structure damage directly. Compared with the traditional calculation method, it can reduce computation cost and save time.