ASME STP-PT-082

Abstract

INTRODUCTION ASME ST-LLC request-for-proposal RFP-16-03 (project STIN-0151) sought the calculation of stress intensity K factors for external surface cracks in thick-walled cylinder vessels. The 1040 crack analysis cases for this project extend the K factor solutions available in the API 579-1/ASME FFS-1 [1] Annex C tables. This project supplements the results from ASME ST- STIN-0130 for the internal crack solutions as identified in ASME ST-LLC’s publication STP-PT-072 [2]. The analysis method uses our FEACrack™ [3] software to generate the three-dimensional (“3D”) crack meshes, described below. Quest Integrity developed the FEACrack™ software, a commercial product for 3D crack mesh generation and analysis, and has continuously verified its robustness and suitability for analyses such as in the current work. This software was originally released in 1998, and was used to create most of the K factor solutions in Annex C of API 579 [1][4][5]. FEACrack™ creates complete and readyto- run Abaqus™ [6] input files, including the syntax to define the J-integral calculation, to allow efficient analysis of many crack cases. The finite element analysis cases are run for each crack mesh using the Abaqus™ solver. Abaqus™ also provides the crack front J-integral calculation at the crack front nodes. FEACrack™ provides automated post processing to help inspect the mesh and crack front J-integral results and tabulate the stress intensity solution factors. FEACrack™ automatically computes the stress intensity K factor from the J-integral using the elastic material properties, and examines the J-integral path dependence to indicate any issues with a result. The stress intensity results are reported as non-dimensional geometry G factor values, described in Section 1.2. The result values are tabulated in the appendices. Plots of the results for all the cases examined and for result trends are also shown in the appendices. Each appendix begins with a description of the values or plots within the particular appendix.