3D thermomechanical buckling analysis of perforated annular sector plates with multiaxial material heterogeneities based on curved B-spline elements

In the present paper, thermomechanical buckling of perforated functionally graded annular sector plates under uniform temperature rises and radial, circumferential or biaxial mechanical loads are investigated. Furthermore, effects of the circular cutouts on the buckling strength and deformation pattern are studied. Influence of the heterogeneity of material of the FGM sector in radial, circumferential, and transverse directions on the thermomechanical buckling is investigated for plates without or with one or two holes. Governing equations are derived based on the 3D energy-based theory of elasticity and buckling occurrence is detected by Treftz instability criterion. A novel curved 3D B-splined C2-continuous element is proposed to trace the inter-element variations of the displacements and stresses and model the geometric discontinuities (cutouts). A proper algorithm is also proposed to relate events of the original cylindrical coordinates to those of the natural coordinates and vice versa. Instead of using the common von Karman assumptions, the most general form of the strain tensor in curvilinear coordinates is used. Finally, effects of the sector dimensions, size and orientation of the cutout, heterogeneity direction, direction of the mechanical loads and the combination of the thermal and mechanical loads on the buckling loads and mode shapes are investigated.