Stress analysis of pipe bends subjected to internal fluid pressure using the finite element technique

Ovality and thinning are the commonly observed shape irregularities that are introduced during the forming process of pipe bends. Pipe bends with ovality and thinning are subjected to higher stresses than pipe bends with perfectly circular cross-sections. The stresses introduced in pipe bends with different ovality and thinning for a particular internal pressure are calculated using the finite element method. The constant allowable pressure ratio for different ovality and thinning is presented at different bend radii. The allowable pressure ratio increases, attains a maximum, and then decreases as the values of ovality and thinning are increased. A mathematical correlation to determine the allowable pressure in terms of bend ratio, pipe ratio, per cent thinning, and per cent ovality is presented.