PSI - Issue 42

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

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 42 (2022) 762–768

© 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the 23 European Conference on Fracture – ECF23 Abstract This paper highlights the main impacts of HFMI (High Frequency Mechanical Impact) technology on increasing the fatigue resistance and extending the fatigue life of welded joints. In the case study there are SN curves of T-welded joints made of two different steels (conventional steel S235JR and high strength steel S460MC). For both materials there is a comparison of SN curves with and without HFMI treatment. Both samples are loaded by bending for cycle asymmetry R = 0. The failure criterion is a decrease in stiffness caused by the formation of a macrocrack. The results of fatigue testing are then applied in a parametric study, which assumes a random loading of a selected structural detail in a railway application. Opportunities and barriers of the implementation of HFMI in practice are mentioned and documented according to results of laboratory experiments, which take place in cooperation with the university research center and the manufacturer of railway vehicles. © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of 23 European Conference on Fracture - ECF23 Keywords: High-strength steels; HFMI; Railway vehicles; weld; SN curve 1. Introduction The Regional Technological Institute is currently working on many projects dealing with increasing the fatigue life of welds since the service life of welded joints is an important topic in many areas of research. Methods of additional processing of welds have been known since the 1970s. These are methods based on improving the geometry of the critical weld points for the initiation and propagation of a fatigue crack and at the same time adjusting the residual stress in this area. Among these methods are hammering, ball rolling, rolling, teming, and remelting of the weld heel with a TIG welder can also be counted among these methods. The collective term for a larger number of modifications of the weld toe is HFMI. It includes Ultrasonic impact treatment (UIT), Ultrasonic peening (UP), Ultrasonic peening treatment (UPT), High frequency impact treatment This is an open access article und 23 European Conference on Fracture - ECF23 Opportunities and partial problems of HFMI implementation in design of welded structures of rail vehicles Miloslav Kepka jr. a , Miloslav Kepka a , Jan Tittel a a Regional Technological Institute, Faculty of Mechanical Engineering, University of West Bohemia, Univerzitni 2732/8, 301 00 Pilsen, Czech Republic

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of 23 European Conference on Fracture - ECF23

2452-3216 © 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the 23 European Conference on Fracture – ECF23 10.1016/j.prostr.2022.12.096