PSI - Issue 19

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

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Procedia Structural Integrity 19 (2019) 267–274

Fatigue Design 2019 Design recommendations for fatigue-loaded hollow section K-joints with gap Jennifer Hrabowski a *, Stefan Herion a a KoRoH GmbH – CCTH Center of Competence for Tubes and Hollow Sections, Schoenfeldstrasse 8, 76131 Karlsruhe, Germany Fatigue Design 2019 Design recommendations for fatigue-loaded hollow section K-joints with gap Jennifer Hrabowski a *, Stefan Herion a a KoRoH GmbH – CCTH Center of Competence for Tubes and Hollow Sections, Schoenfeldstrasse 8, 76131 Karlsruhe, Germany

Abstract Abstract

The existing and approved rules for the fatigue design of hollow section joints have origin in the CIDECT Design Recommendations, which are based on experimental investigations made in the 1990s and earlier. Conclusions of recent research, based on fatigue tests and numerical investigations as well, are used to extend the scope to high strength steels up to S700 and various load cases. The nominal stress method as well as the structural stress method is considered. Drawbacks and opportunities of existing design recommendations are exemplified. Further instructions for fatigue resistant constructions are given to enable a safe and economic design of K-joints with gap and its girders. The existing and approved rul s for th fatigue design of hollow section joints have origi in the CIDECT Design Recommendations, which are based on experimental investig tions made in the 1990s and earlier. Conclusions of recent research, b sed on fatigue tests a d numerical inv stigations as well, are used to extend t e scope to high strength steels up to S700 and various loa cases. The nomin l stress m thod as well as t structural stress method is considered. Drawbacks and opportunities of xisting design recommendatio s are exemplified. Further instructions for fatigue resistant constructions are given to enable a safe and economic design of K-joints with gap and its girders.

© 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: Fatigue, hollow sections, K-joints, high strength steel Keywords: Fatigue, hollow sections, K-joints, high strength steel

1. Introduction 1. Introduction

The K-joint with gap made of hollow sections, as defined in Fig. 1, is the most common joint type for lattice girders as used for jack-up rigs, wind energy converters, bridges, crane structures, agricultural machinery or amusement rides. The existing and approved rules for the fatigue design of hollow section joints have origin in the CIDECT Design Recommendations (Zhao et al., 2001), which are based on experimental and numerical investigations on joints with small wall thickness made of steel with yield strengths of 235 or 355 MPa made in the 1990s and earlier. Since then, a lot has changed in the development of materials, manufacturing and computer-aided design and computer-aided The K-joint with gap made of hollow sections, as defined in Fig. 1, is the most common joint type for lattice girders as used for jack-up rigs, wind energy converters, bridges, crane structures, agricultural machinery or amusement rides. The existing and approved rules for the fatigue design of hollow section joints have origin in the CIDECT Design Recommendations (Zhao et al., 2001), which are based on experimental and numerical investigations on joints with small wall thickness made of steel with yield strengths of 235 or 355 MPa ade in the 1990s and earlier. Since then, a lot has changed in the development of materials, manufacturing and computer-aided design and computer-aided

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. * Correspon ing author. Tel.: +49-721-8244890-30; fax: +49-721-8244890-99. E-mail address: jennifer.hrabowski@koroh.de * Corresponding author. Tel.: +49-721-8244890-30; fax: +49-721-8244890-99. E-mail address: jennifer.hrabowski@koroh.de

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Fatigue Design 2019 Organizers. 10.1016/j.prostr.2019.12.029