A unified approach to simulate the creep-fatigue crack growth in P91 steel at elevated temperature under SSY and SSC conditions

Author(s):  
Marcello A. Lepore ◽  
Angelo R. Maligno ◽  
Filippo Berto
Author(s):  
Y. Kayser ◽  
S. Marie ◽  
M. H. Lacire ◽  
S. Chapuliot ◽  
B. Drubay

A large program is performed in France in order to develop, for the design and operating FBR plants, defect assessment procedures and Leak-Before-Break methods (L.B.B.). The main objective of this A16 guide is to propose analytical solutions at elevated temperature coherent with those proposed at low temperature by the RSE-M (RSE-M, 1997). The main items developed in this A16 guide for laboratory specimen, plates, pipes and elbows are the following: • Evaluation of ductile crack initiation and crack propagation based on the J parameter and material characteristics as JR-Δa curve or Ji / Gfr. Algorithms to evaluate the maximum endurable load under increasing load for through wall cracks or surface cracks are also proposed. • Determination of fatigue or creep-fatigue crack initiation based on the σd approach calculating stress and strain at a characteristic distance d from the crack tip. • Evaluation of fatigue crack growth based on da/dN-ΔKeff relationship with a ΔKeff derived from a simplified estimation of ΔJ for the cyclic load. • Evaluation of creep-fatigue crack growth adding the fatigue crack growth and the creep crack growth during the hold time derived from a simplified evaluation of C*. • Leak-Before-Break procedure. The fracture mechanic parameters determined in the A16 guide (KI, J, C*) are derived from handbooks and formula in accordance with those proposed in the RSE-M document for in service inspection. Those are: • The KI handbook for a large panel of surface and through-wall defects in plates, pipes and elbows. • Elastic stress and reference stress formula. • Analytical Js and Cs* formulations for mechanical and through thickness thermal load. The main part of the formula and assessment methodologies proposed in the A16 guide are included in a software, called MJSAM, developed under the MS Windows environment in support of the document. This allows a simple application of the analysis proposed in the document.


2010 ◽  
Vol 4 (9) ◽  
pp. 1410-1426 ◽  
Author(s):  
Tae Wuk WOO ◽  
Masao SAKANE ◽  
Kwang Soo KIM ◽  
Kaoru KOBAYASHI ◽  
Hyun Chul PARK

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