Evaluation of the central crack effect on the buckling behavior of an isogrid plate with optimized stiffening lattice

The use of thin plates with grid reinforcements has a widespread application in the design of lightweight structures. In this paper, the effect of the presence of a central crack on the critical buckling load of a thin plate reinforced with an isogrid lattice under pressure load is evaluated. The plate is reinforced by four horizontal and three diagonal ribs, which create hexagonal grids. The modeling and analysis is preformed numerically by finite element method using Abaqus software; and the influences of crack length and orientation, and Poisson's ratio on buckling load coefficients are investigated. The results show that the effect of these parameters is strongly influenced by the boundary conditions. In plates with simple supports on all four edges, increasing the length of the crack increases the critical buckling load and increasing the crack angle reduces the load. On the other side, when the longitudinal edges of the plate are free, the previous trend changes. As the increase in the length of the crack decreases the critical buckling load and the increase in the crack angle increases the critical buckling load. Also, the change in Poisson's ratio in both of the supporting conditions has little effect on stability of the plate; and the results show that increasing the Poisson's ratio slightly reduces the critical buckling load.