PROBABILISTIC PROGRESSIVE BUCKLING OF TRUSSES

A three-bay, space, cantilever truss is probabilistically evaluated to describe progressive buckling and truss collapse in view of the numer ous uncertainties associated with the structural, material, and load v ariables that describe the truss. Initially, the truss is deterministi cally analyzed for member forces, and members in which the axial force exceeds the Euler buckling load are identified. These members are the n discretized with several intermediate nodes, and a probabilistic buc kling analysis is performed on the truss to obtain its probabilistic b uckling loads and the respective mode shapes. Furthermore, sensitiviti es associated with the uncertainties in the primitive variables are in vestigated, margin of safety values for the truss are determined, and truss end node displacements are noted. These steps are repeated by se quentially removing buckled members until onset of truss collapse is r eached. Results show that this procedure yields an optimum truss confi guration for a given loading and for a specified reliability.