Papers by Keyword: Geometrical Imperfection

Abstract: As dual-phase (DP) steel sheet is widely used in automotive manufacture, researches on failure mode of DP steel have been carried out experimentally and numerically in recent years. In this paper, failure mode of DP 780 steels with geometrical imperfection, which was assumed as a consequence of previous process, was investigated via a microstructure approach utilizing RVE technique. Multiple damage models were applied on characteristic microstructures and the modified pointed-ended geometrical imperfection was ingrained. Considering the progress of crack evolution, the depth and the location of geometrical imperfection were critical factors in determining the mode of crack initiation and propagation. Essentially, geometrical imperfection influenced the failure mode of investigated DP steel via aggravating the structural heterogeneity.

Abstract: Von Misses truss is one of the best examples to explain nature of non-linear solution and define the snap-through. Linear buckling analysis and nonlinear finite element approaches are compared in presented paper. At the present time theoretical models for the evaluation of the ultimate load assume a structure with imperfections. The peculiarities of the effect of the magnitude and mode of initial imperfections are investigated. Effect of member stiffness on the load level in critical point of nonlinear solution, as well as the relative position with respect to the critical load from buckling analysis are analyzed. To obtain the nonlinear equilibrium paths, Newton-Raphson iteration algorithm has been used. Obtained results are compared with those gained using ANSYS system.

Abstract: The equilibrium equations of elastic support circular arches considering geometrical imperfections are deduced from variation principle. And the relations between external load, radial displacement and axial forces are determined; also the equilibrium conditions of snap-through buckling and bifurcation buckling in circular arch are ascertained respectively. Further, influences of geometrical imperfections and elastic supports on in-plane stability are analysis with analytical and finite element (FE) method. And the compared results display that the two methods coincide with each other very well for smaller opening angle in circular arches. The geometrical imperfections have only certain effects on the buckling path, while the elastic support rigidity play a significant role in both the path and critical load of snap-through buckling.