The Study On Buckling And Post-buckling Of Corrugated Boxes

The corrugated boxes have been widely used in the field of packaging products nowadays, its properties of stacking strength and cushioning are good, the products can be protected very well. Buckling is the main form when corrugated boxes'damage occurs, so the study about buckling of corrugated boxes has important practical significance and engineering value. In this paper, corrugated boxes 0201 were selected, and the buckling and post-buckling of corrugated boxes were mainly discussed.Corrugated cardboard should be simplified as its structure is complex. Corrugated boards were replaced by the orthotropic homogeneous sheet with the principle that flexural rigidity of corrugated board and equivalent board were equal in the horizontal and vertical direction respectively. Corrugated box has a direct relation with the side board when buckling failure occurs, corrugated board was simplified by the simply supported orthotropic plate, the buckling load of corrugated board was obtained based on the bending equations of sheet, and finally we derived the buckling load formula of corrugated boxes.In order to get the mechanical properties of the material, Tensile tests were performed on liners, corrugated medium; edge compressive tests were performed on corrugated board, We got the load-displacement curve of liners, corrugated medium and corrugated board, and elastic modulus of liners, corrugated medium and corrugated boards were obtained according to the elastic modulus formula. In addition, compression testing were performed on corrugated boxes, compressive strength of corrugated boxes were obtained.In order to analysis post-buckling load of the corrugated boxes conveniently, the finite element model of corrugated boxes were established and linear buckling analysis was needed firstly, the first buckling mode shape in linear buckling analysis as the initial geometric imperfection in nonlinear buckling analysis secondly. Then the finite element model of corrugated boxes were fixed, the overall load performance of corrugated boxes were enhanced by adding ribs in the four corners. Finally, nonlinear buckling analysis were performed on the corrugated boxes, we got the post-buckling load of corrugated boxes.According to the previous idea of buckling analysis of corrugated boxes, finite element model of corrugated boxes with rectangle, oval, round window were established and buckling and post-buckling analysis were done. The feasibility of the finite element method of corrugated boxes was verified again. Finally, we got the regular pattern that post-buckling load of corrugated boxes as sizes and positions of window changed.