COMPUTER CODE FOR PREDICTING THE TWO-DIMENSIONAL NONLINEAR DYNAMIC RESPONSE OF BEAM STRUCTURES SUBJECTED TO TRANSIENT LOADS AND IMPACTS

This paper describes the MENTOR (Meredith Engineering Nonlinear Transient Oscillatory Response) II code, a finite element computer program for the analysis of planar beam structures undergoing large elastic-plastic deformations. The analysis includes the modeling of beam cross-section collapse due to either the direct application of a “crushing load” and/or extreme changes in curvature of the beam neutral axis. Collisions are treated within the MENTOR II program via a monitoring procedure which detects inter-element contact, determines the relative indentations, and calculates the associated local reactive pressure.

The structural equations of motion are derived using Hamilton's principle and are discretized over the beam length using finite elements which are based upon cubic tangential and transverse displacement fields. The integration in time of the equations of motion is accomplished by use of an explicit central difference scheme.

The validity of the MENTOR II program is illustrated by comparing numerical solutions with experimental results for a variety of problems involving large deformation, elastic-plastic behavior.