Postcritical State of a Ribbed Rectangular Disk under the Action of a Unidirectional Linearly Variable Load.

A solution is obtained for the problem of the stability loss of a ribbed rectangular disk, freely supported along its whole circumference and subjected to the action of a linearly variable load. It is assumed that the disk is strengthened by a longitudinal rib symmetrical to its central plane. An open profile rib characterized by different stiffnesses during bending and compression is assumed. The problem is solved in a nonlinear formulation by the power method. On the basis of the formulas derived, an analysis is made of the effect of the parameters of the reinforcing rib on the deflections and stresses of the disk in the postcritical state. In addition, the limit load is determined as a function of the material and structural parameters of the disk and rib.