Ultimate Strength and Plastic Collapse Behavior of Statically Indeterminate Pipes with Crack and Compliances.

Abstract

The effects of crack size, compliance and fracture toughness on plastic collapse behavior and ultimate strength of a statically indeterminate pipe system have been analyzed. The main results obtained are as follows. 1) For the case of JIC≥500kN/m and dJ/da≥100MN/m2, these parameters have little effect on plastic collapse behavior and ultimate strength. 2) The J-integral value at the onset of plastic collapse depends on crack size, pipe span length, compliance and loading system. However the highest value is lower than 8 MN/m. 3) The plastic rotation angle of plastic hinge at the onset of collapse is lower than 0.2 [rad]. This value is important when considering the LBB (leak before break) behavior of a piping system. 4) The analysis method adopted in this paper is useful and convenient for evaluation of the tearing instability behavior of a piping system.