Issue 52

J. Kasivitamnuay et alii, Frattura ed Integrità Strutturale, 52 (2020) 163-180; DOI: 10.3221/IGF-ESIS.52.14 163 Object-Oriented Software for Fitness-For-Service Assessment of Cracked Cylinder Based on API RP 579 Jirapong Kasivitamnuay, Pairod Singhatanadgid Chulalongkorn University, Thailand jirapong.K@chula.co.th, http://orcid.org/0000-0002-9933-7652 pairod.S@chula.ac.th , http://orcid.org/0000-0002-4972-753X A BSTRACT . Fitness-for-service assessment of a cracked component intends to evaluate its remaining strength and remaining life to support the implementation of a maintenance plan. This research aims to develop a fitness-for-service assessment software to facilitate the task. The software development process included identifying the software specifications, designing the software structure, manipulating the information in the standard for programming, the graphical user interface design, and finally verification. The assessment procedure employed in this study was the third edition of the standard API RP 579. The software structure was designed using an object- oriented concept. The software can perform integrity assessment levels 1, 2, and 3 option B, leak-before-break assessment, and remaining life assessment for a cracked cylinder that has a through-thickness crack or semi-elliptical surface crack oriented in an axial or circumferential direction. The applied loads could be a nominal axial force, bending moment, and internal pressure, as well as stress profiles perpendicular to the crack plane due to mechanical, thermal, and residual stresses. Accuracy of the software was demonstrated by applying it to example problems. Some aspects of the software extensibility were conceptually discussed. K EYWORDS . API 579; Fitness-for-Service; Fracture mechanics; Object- Oriented programming; Pressure vessel. Citation: Kasivitamnuay, J., Singhatanadgid, P., Object-Oriented Software for Fitness-For- Service Assessment of Cracked Cylinder Based on API RP 579, Frattura ed Integrità Strutturale, 52 (2020) 163-180. Received: 25.12.2019 Accepted: 04.02.2020 Published: 01.04.2020 Copyright: © 2020 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION crack-like flaw is one of the major service degradation mechanisms for pressure vessels and piping. Fitness-for- service (FFS) assessments are conducted on these cracked components to quantitatively evaluate their suitability for operation and to determine the remaining service life. Numerous professional FFS assessment procedures have been developed worldwide, as reviewed by Hasegawa [1]. To enhance FFS assessment activities, Filiou et al. [2] suggested the development of FFS software. Researchers from universities, organizations, and companies have attempted to develop these software packages [3-14]. The computational basis within these packages may refer to a single specific FFS standard [3, 6, 9, 11, 14], an integration of several FFS standards [12, 13], or a direct implementation of a fracture mechanics methodology without referring to any standard [4, 5, 7, 8, 10]. A