Author(s)

N Gubeljak & S Kravanja

Abstract

The Structural INTegrity Assessment Procedure-SINTAP enables determination of the residual service life-time of a structural component with a crack. The SINTAP procedure makes it possible to follow changes of the maximum limit load during crack propagation. In this paper we have introduced the SINTAP procedure into the design stage on a real industrial example for the purpose of replacing the cracked structural component. We have connected SINTAP algorithms to the optimization techniques for this reason. Optimization was performed using the non-linear programming (NLP) approach. We obtained the optimal design and material of the structural component in the critical cross section by considering geometrical constraints. 1 Introduction The potential danger of plane flaws at the critical section of a structure requires an optimal design approach against brittle fracture. This design should take into account one of the procedures for structural integrity assessment e.g. EPRI [l], R6 [2], SINTAP [3], etc. This procedure requires three main groups of input data: -material: -stress-strain behavior (mechanical properties) -crack resistance parameter (KIc, CTOD,, Jc) -load: -loading regime of primary stresses -secondary stress (residual stresses) -geometry: -geometry of component (design of component) -geometry of flaw In the optimization design process it is possible to treat the material (stress- strain behavior) and a geometry (size of critical section) of component as a

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