PSI - Issue 19

Available online at www.sciencedirect.com Structural Integrity Procedia 00 (2019) 000 – 000 ScienceDirect Structural Integrity Procedia 00 (2019) 000 – 000 ScienceDirect Available online at www.sciencedirect.com

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Procedia Structural Integrity 19 (2019) 711–718

Fatigue Design 2019 Updating the Master S-N Curve to Account for Run-Out Data: Application to Piping Vibrations Edrissa Gassama a , Michael F. P. Bifano a , Anthony J. Feller a , Daniel W. Spring a * a E 2 G | The Equity Engineering Group, Inc., 20600 Chagrin Blvd., Suite 1200, Shaker Heights, 44122, USA In the very high-cycle fatigue regime there is a well-known lack of data for the assessment of welded joints. This lack of data has led to Codes and Standards with a wide range of recommendations. Most of these recommendations are justified by experience and lack a well-documented technical basis. The difficulty in testing at very high cycles is that the tests currently take too long to be practical and are often suspended between 10 6 and 10 7 cycles. However, in piping vibration applications the system may undergo more than 10 8 cycles per year. Since much of the experimental data in this very high-cycle regime is run- out or “censored” data, we explore approaches to extract the information contained in such data and infer the behaviour of the Master S-N curve in the very high-cycle regime. This paper presents an approach to account for censored data to provide a basis for extending the Master S-N curve to the very high-cycle fatigue regime for welded joints. Fatigue Design 2019 Updating the Master S-N Curve to Accoun for Run-Out Data: Application to Piping Vibrations Edrissa Gassama a , Michael F. P. Bifano a , Anthony J. Feller a , Daniel W. Spring a * a E 2 G | The Equity Engineering Group, Inc., 20600 Chagrin Blvd., Suite 1200, Shaker Heights, 44122, USA Abstract In the very high-cycle fatigue regime there is a well-known lack of data for the assessment of welded joints. This lack of data has led to Codes and Standards with a wide range of recommendations. Most of these recommendations are justified by experience and lack a well-documented technical basis. The difficulty in testing at very high cycles is that the tests currently take too long to be practical and are often suspended between 10 6 and 10 7 cycles. However, in piping vibration applications the system may undergo more than 10 8 cycles per year. Since much of the experimental data in this very high-cycle regime is run- out or “censored” data, we explore approaches to extract the information contained in such data and infer the behaviour of the Master S-N curve in the very high-cycle regime. This paper presents an approach to account for censored data to provide a basis for extending the Master S-N curve to the very high-cycle fatigue regime for welded joints. Abstract

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. © 2019 The Authors. Published by Elsevier B.V. P er-review under r sponsibility of th Fatigu Design 2019 Organizers. Keywords: Fatigue Life; Master S-N Curve; Censored Data; Very High Cycle Fatigue, Vibration

Keywords: Fatigue Life; Master S-N Curve; Censored Data; Very High Cycle Fatigue, Vibration

1. Introduction

1. Introduction

The Master S-N curve has long been used as the basis for determining the resistance of welded components to fatigue damage, and still serves as the state-of-the-art. For example, in the 2016 release of API 579-1/ASME FFS-1 (API 579), a new part related to fatigue damage was introduced wherein the Master S-N curve was selected as the The Master S-N curve has long been used as the basis for determining the resistance of welded components to fatigue damage, and still serves as the state-of-the-art. For example, in the 2016 release of API 579-1/ASME FFS-1 (API 579), a new part related to fatigue damage was introduced wherein the Master S-N curve was selected as the

* Corresponding author. Tel.: +1-216-658-4752. E-mail address: dspring@e2g.com

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. 2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. * Corresponding author. Tel.: +1-216-658-4752. E-mail address: dspring@e2g.com

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. 10.1016/j.prostr.2019.12.077