Numerical analysis of biaxial elasto-plastic buckling of perforated rectangular steel plates applying the Constructal Design method

Abstract

Thin plates are constantly used in many applications of the structural designs, like naval, aerospace, civil and offshore platforms. When the supported loading is compressive along the plane of plate, it can suffer with an instability phenomenon called buckling which can be elastic or elasto-plastic. In addition, many times the plated structures need to be designed with cutouts for the most varied reasons: access, maintenance, crossing pipes and reducing of weight, for example. The presence of holes affects the mechanical behavior of the plate and it must be investigated. This work used Finite Element Method associated to Constructal Design method and Exhaustive Search technique to find the optimal geometries, i.e. the ones that maximize the Normalized Ultimate Stress, for simply-supported rectangular steel plates under biaxial compressive loading. It was analyzed the size and geometry of the centered elliptical hole. It was observed that the presence of cutout reduces the mechanical strength of the plate and also, the same occurs when the hole size is increased. Constructal Design method has been proved as an effective method to analyze buckling problems conducting to the best geometry for each studied case. For the simulated cases it is evident the relevance of geometric evaluation of elliptical perforations, once the simply variation of geometry can provide differences until around 42% when comparing the optimum and the worst geometries, for the same hole size.