Analysis of the limiting plastic state of a thick-walled bent pipe

We propose an engineering approach to the determination of the limiting state of a bent pipe. In the first stage, the influence of some groups of external loads is analyzed separately. Then it is necessary to determine the coefficient of reduction of internal moments under the combined action of external bending moments and internal pressure. In the final stage, we use a specially developed general approach to the analysis of the limiting state at a given point of the cross-section of a bent pipe for the obtained system of internal forces, namely, for the bending moment, the tensile force acting in the circumferential direction, and longitudinal and tangential forces. We also demonstrate the possibility of application of the obtained results to the approximate analysis of cracks and three-dimensional defects appearing in a bent pipe. © 1998 Plenum Publishing Corporation.