The concepts of limit load and reference stress have been widely used in structural engineering design and component integrity assessment, especially in Nuclear Electric's (formerly CEGB) R5 and R6 procedures. The referencestress method has been proven to be successful in problems pertaining to creep growth, rupture damage, creep buckling, and more recently, elastic–plastic fracture toughness. An approximate method of referencestress determination relies on prior knowledge of limit loads for various configurations and loadings. However, determination of the limit loads for the problems with complicated geometric forms and loading conditions is not a simple task. In the present paper, a numerical solution method for radial loading is presented, the mathematical programming formulation is derived for the kinematic limit analysis of 3D structures undermulti-loading systems, and moreover, a direct iterative algorithm used to determine the referencestress is proposed which depends on the evaluation of limitload. The numerical procedure is applied to determine the limitload and referencestress of defectivepipelinesundermulti-loading systems. The effects of four kinds of typical part-through slots on the collapse loads of pipelines are investigated and evaluated in detail. Some typical failure modes corresponding to different configurations of slots and loading forms are studied.
|Number of pages||10|
|Journal||International Journal of Pressure Vessels and Piping|
|Publication status||Published - 1998|
- limit load
- reference stress
- loading path
- mathematical programming