Tetsuo Iwakuma

Instability phenomena of a rectangular elastic plate under bending and shear

Abstract This paper focuses on the instability phenomena of an elastic rectangular plate under pure bending which emerge after the occurrence of the primary buckling. The mechanisms of this instability behavior are investigated phenomenally throughout the analysis of load-deflection simulations. The relationships between the characteristics of this instability and the boundary conditions of a plate are also discussed. The effect of initial deflections on the post-buckling paths and secondary instability phenomena is examined from the viewpoint of imperfection-sensitivity. Finally, it is presented that a plate also shows the similar instability phenomena when subjected to unequal bending and shear.

Consistency of straight-beam approximation of a thin-walled circular beam

Practically curved members including circular arches are often analyzed by an approximate method using an assemblage of straight beam elements. Here a stiffness equation of such an assemblage of straight beam elements is introduced, and it is shown that the discretized equation converges to the exact field equation of a thin-walled circular beam as the size of each element becomes infinitesimally small. The stiffness equation with the coupled in-plane and out-of-plane motion can be applied to arbitrary circular beams with arbitrary radii no matter how deep they are, as long as the assumptions of the thin-walled curved beams hold.