Limit analysis for piping branch junctions with local wall- thinning under pressure

Currently, the most widely recognized limit analysis techniques utilizing finite element methods are based on mathematical analysis of optimization problems using the lower and upper bound limit load theorems, but their computing needs are excessive for realistic problems. Elastic analysis was used to develop a simple technique called the elastic compensation method to calculate the limit load for complex structures. The method was used in combination with a three-dimensional finite-element analysis to calculate the limit load for equal-diameter piping branch junctions. The results compare well with a detailed elasto-plastic analysis showing that the simple elastic compensation procedure can provide good estimates of the bearing capacities of complex three-dimensional structures. Calculational results also show that the local wall-thinning of main pipes most greatly affects the limit load capacity for piping branch junctions.