Buckling of composite plate made of curvilinear fiber with linear and nonlinear fiber orientation variation

In this research, effect of curvilinear fibers on the buckling load improvement of composite plates was studied. Two paths for curvilinear fiber were considered, namely, the linear variation of fiber angle and the nonlinear variation of fiber angle (constant curvature). The fiber orientation varies linear and nonlinear with the coordinates of plate in these two mentioned paths respectively. In the previous researches, linear variation of fiber angle was usually investigated. However, the results were not compared with those of the other paths. In this research, comparisons between the two paths of the linear variation of fiber orientation and the constant curvature of composite plates with and without cutout were performed. ABAQUS finite element software was used for modeling and analysis. Results show that for composite plates without cutouts and with intended dimensions, material, lay-up and boundary conditions in the ideal state, the linear variation of fiber orientation caused ten percent increase in the buckling load in comparison with the constant curvature path. However, by considering the minimum practical radius constraint of the manufacturing method, the constant curvature path shows better results. According to applied boundary conditions, the mechanism of buckling load increase with curvilinear fibers is due to shifting the load from the center of plate to the side edges. Two geometries of cutout, circular cutout with different diameters and elliptical cutout with different aspect ratios were also considered. The results show that in the models with cutout by considering the manufacturing constraints, both paths have similar buckling load approximately.