DIRECT STRAIN MEASURE FOR LARGE-DEFORMATION ANALYSES OF BEAM STRUCTURES

A nonlinear kinematics called the direct strain measure is proposed fo r large deformation and finite rotation analyses of a two-node Timoshe nko beam. The kinematics extracts pure elastic deformations without de riving any virtual frame to describe rigid body motion, internal force and stiffness matrices are derived to constitute a Newton's method fo r finding the solution. Computational results show that the present me thod is valid for Timoshenko beams whose relative angular displacement in an element is less than 0.5 rad.