Lower and upper bound limit analyses for pipeline with multi-slots of various configurations

Using the finite element method and mathematical programming techniques, a simplified numerical method for both lower and upper bound limit analyses o f a 3-D structure has been developed in our previous work. In this paper, t he lower and upper bound limit loads of the 3-D pipeline with one or two pa rt-through slots of various geometrical configurations are calculated by th e proposed method. The slots considered here are small spherical slots, cir cumferential slots, axial slots and large area slots. The loading considere d includes internal pressure, axial tension and bending moment at both ends , and the radial loading path scheme is adopted. The effects of slot number and type on the load carrying capacity of the pipeline are discussed in de tail. The discrepancy between lower and upper bounds is below 20%. All the numerical results confirm the applicability of the procedure. (C) 2000 Else vier Science Ltd. All rights reserved.