Fitness-for-Service Methodology Based on Variational Principles in Plasticity

Abstract

A variational formulation in plasticity has been used to develop improved limit load estimation technique, such as the m-alpha method. Lower bound limit load estimates are especially germane to design and fitness-for-service assessments. The concept of “integral mean of yield” has been applied to problems involving locally thinned areas (LTA) and local hot spots in the context of industrial pressure vessels and piping. Simplified procedures for “fitness-for-service” assessment, suitable for use by plant engineers, have been developed. The results are compared with the corresponding inelastic finite elastic analyses.