A hybrid approach to the transient collapse analysis of thin walled frameworks I Original Research Article

A compound beam element for the transient hybrid finite element analysis have been developed. The new element is a combination of an elastic beam and nonlinear rotary springs whose behaviour in the elastic/plastic and deep collapse range is controlled by inputted moment-rotation curves. The element formulation is based on the rigid convected co-ordinate procedure similar to the one used by the Belytschko-Schwer (B-S) beam element [1]. The element mass and stiffness matrices have been derived and the stiffness matrix dependency on the spring behaviour explained. Semidiscretized equations of motion are discretized in time by the central difference method.