Frame Instability and Strain Hardening in Plastic Theory

The general problem of the effect of strain hardening on the elastic-plastic failure loads of plane structural frameworks is considered. A general computer analysis is described that enables a full examination of the problem to be made. Some results of this analysis are presented, and a comparison with the large-scale test results of earlier authors is made. It appears that the rigid-plastic-rigid theory suggested by Horne is inadequate when applied to more complex structures than those considered in his initial investigations. In the absence of any method of taking account of the effects of strain hardening and frame instability in a simple plastic analysis, it is concluded that the computer approach provides the only rational solution to the problem.