INTERNAL VARIABLE FORMULATIONS FOR THE PLASTIC ANALYSIS OF PLANE FRAMES

There are a number of methods available for the plastic analysis of pl ane frames; of these the most widely used are those which are rooted i n mathematical programming techniques. This paper presents a formulati on which utilizes the thermodynamically based internal variable approa ch where plastic hinges are characterized as internal variables. The a lgebraic equations resulting from the formulation are versatile and it is illustrated how they can be incorporated in an algorithm to solve incremental problems. A number of examples illustrate the application and effectiveness of the formulation.