EXACT STABILITY MODEL OF SPACE FRAMES

The buckling loads are, in general, those for which \K\ = 0, where K i s the stiffness matrix. In this case, K is a transcendental function o f the buckling load lambda. The Wittrick and Williams' algorithm consi sts of finding how many buckling loads have been exceeded at each iter ation. Coupled with the bisection method, this algorithm is infallible , but sometimes the convergence rate is slow. To accelerate the conver gence, a new method for computing the buckling loads is presented. Thi s method can be considered as an improvement on the bisection method o f Wittrick and Williams' algorithm. An exact geometric matrix which is a function of the buckling load I, is derived. The stiffness and geom etric matrices are used to perform a linearized eigenproblem combined with the Wittrick and Williams method. Copyright (C) 1996 Elsevier Sci ence Ltd