PSI - Issue 19

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

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Procedia Structural Integrity 19 (2019) 123–129

Fatigue Design 2019 Crack growth arrester using “ gourd-shaped-insert-plate ” Yoichi Yamashita a,* , Takao Murakami a , Youjirou Akizuki b a IHI Corporation, 1 Shin-Nakahara-Cho Isogo-ku, Yokohama 235-8501, Japan b Kobe Material Testing Laboratory, Kobe, Japan Fatigue Design 2019 Crack growth arrester using “ gourd-shaped-insert-plate ” Yoichi Yamashita a,* , Takao Murakami a , Youjirou Akizuki b a IHI Corporation, 1 Shin-Nakahara-Cho Is go-ku, Yokohama 235-8501, Japan b Kobe Material Testing Laboratory, Kobe, Japan

Abstract In accordance with aging infrastructure systems such as steel bridges, fatigue of metals becomes serious risks. Fatigue crack may lead the structure to catastrophic failure. Countermeasures against fatigue failure are required. “Crack growth arrest and retardation system” using “ gourd-shaped-insert-plate ” has been developed as a high performance and easy construction method against fatigue crack, by generating fatigue crack closure force and reduce crack tip opening displacement and stress concentration at the fatigue crack tip. Arrester was applied to CT (Compact Tension) specimen and also mockup of steel bridge deck, in order to validate performance of the system. Fatigue crack growth rates of the specimens with arrester were 1/10 ~ 1/2 of those without arrester. And apparent threshold stress intensity factor range was increased by about 10~20 MPa√ through using only few gourd-shaped arresters. Also the arrester was applied to the fatigue crack in a mockup of steel bridge deck. Without arrester, fatigue crack growth occurred in accordance with the increase of loading cycles, on the other hand, fatigue crack growth was arrested after installing the arrester in the mockup of steel bridge deck. And to enable quantitative fatigue life assessment in fatigue design, fracture mechanics based-crack closure model with spring elements for the arrester has been verified with good accuracy for fatigue crack growth rate in the tests using CT specimens. Abstract In accordance with aging infrastr cture systems such as steel bridges, fatigue of met ls b comes serious risks. Fatigue crack m y lead the structure to catastrophic failure. Count rmeasures against fatigue failure are required. “Crack growth arre t and retardation system” using “ ourd-shaped-insert-plate ” has been devel ped as a high performan e and easy construction method against fatigue crack, by generating fatigue crack closure force and reduce crack tip opening displacement and stress concentration at the fatigue crack tip. Arrester was applied to CT (Compa t Tension) specimen and also mockup of steel bridge deck, in order to validate performance of the system. Fatigue crack growth rates of the specimens with arrester were 1/10 ~ 1/2 of t ose without arrest r. And app rent thr hold stress intensity factor r nge was increased by about 10~20 MPa√ through using only few g rd-shap d arrest rs. Also the arrester was applied to the fatigue crack in a mockup of steel bridge d ck. Without arrester, fatigue cr ck growth occurred in accordanc with the increase of loading cycles, on the other hand, fatigue crack growth was arrested after installing the arrester in t e mockup of steel bridge deck. And to enable quantitativ fatigu life ass ssment in fatigue design, fracture mechanics based-crack closur model with spring elements for the arrester has been verified with good accuracy for fatigue crack growth rate in the tests using CT specimens.

© 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. Peer-review under responsibility of the Fatigue Design 2019 Organizers. Keywords: Crack arrester; Gourd-shaped-insert-plate; Fatigue crack growth, Steel bridge deck Keywords: Crack arrester; Gourd-shaped-insert-plate; Fatigue crack growth, Steel bridge deck

1. Introduction 1. Introduction

Inspection, maintenance and life assessment design in retrofitting are significant issue in existing old traffic infrastructure. Recently many fatigue cracks have been found in heavy traffic infrastructure systems such as decks of steel bridge which are typically light weight structures with large-span bridges (Kühn (2013)). In accordance with aging infrastructure systems such as steel bridges, fatigue of metals becomes serious risks. Fatigue crack may lead the structure to catastrophic failure. Countermeasures against fatigue failure are required. Inspection, maintenance and life assessment design in retrofitting are significant issue in existing old traffic infrastructure. Recently many fatigue cracks have been found in heavy traffic infrastructure systems such as decks of steel bridge which are typically light weight structures with large-span bridges (Kühn (2013)). In accordance with aging infrastructure systems such as steel bridges, fatigue of metals becomes serious risks. Fatigue crack may lead the structure to catastrophic failure. Countermeasures against fatigue failure are required.

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.

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. 10.1016/j.prostr.2019.12.015