PSI - Issue 28

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

www.elsevier.com/locate/procedia

ScienceDirect ScienceDirect

Procedia Structural Integrity 28 (2020) 561–576 Structural Integrity Procedia 00 (2019) 000–000

www.elsevier.com/locate/procedia

© 2020 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 European Structural Integrity Society (ESIS) ExCo Abstract Fracture surfaces generated under biaxial fatigue (combined bending-torsion loading) was studied presented work. Complexity of the crack path was characterized by normal vectors of elementary flats instead classical roughness parameters (such as arithmetic roughness etc.) or fractal characteristics used in previous studies. Presented method of description is based on normal vectors (or directional angles) and it was designed in order to overcome some disadvantages of old methods. Disadvantages that are typical for surface assessment using classical roughness parameters classical roughness parameters. This method applied on fracture surfaces generated by fatigue. These specimens were made from steel EN 37CrA1Mo 6. In experiments two sets of specimens were used, virgin and specimens with plasma nitrided surface. Description of the fracture surface using normal vectors, resp. their directional angles make it possible to describe the surface as well as by using classical roughness parameters. However, it does not require such a precise selection of the studied profiles. In addition, however, it allows some mapping of the direction of crack propagation. Keywords: Type your keywords here, separated by semicolons ; Fatigue fracture, fracography, bending-torsion loading, normal vectors, triangulation network, square network. 1. Introduction Although engineers and scientists have been paying attention to the fatigue fracture more than 140 years is still one the most important topics in material science. Nowadays, fatigue damage under multiaxial condition is studied predominantly in the case of metallic materials. Also, considerable emphasis is now placed on non-metallic materials, whereas fatigue degradation of these materials has not been studied in the past, see Socie and Marquis (2000) or Schijve (2003). Because, the fracture surface can be considered to be record of the course of degradation process, we can get a lot of information from it. The general availability of the SEM opened up new ways toward the understanding Abstract Fracture surfaces generated under biaxial fatigue (combined bending-torsion loading) was studied presented work. Complexity of the crack path was characterized by normal vectors of elementary flats instead classical roughness parameters (such as arithmetic roughness etc.) or fractal characteristics used in previous studies. Presented method of description is based on normal vectors (or directional angles) and it was designed in order to overcome some disadvantages of old methods. Disadvantages that are typical for s face ass sment using classical roughness param ters classical roughness parameters. This method applied on fracture surfaces generated by f tigue. These specim ns were mad from steel EN 37CrA1Mo 6. In experiments two ets of speci ns were used, virgin and spe imens w th plasma nitrided s rface. Desc iption of the fracture u face using normal vectors, r sp. thei make it po sible to escribe the surface as well as by using clas ical roughness parameters. However, it does not require such a precise selection of the studied profiles. In addition, however, it allows some mapping of the directi of rack propagation. Keywords: Type your keywords here, separated by semicolons ; Fatigue fracture, fracography, bending-torsion loadi g, normal vectors, triangulation network, square network. 1. Int oduction Although engineers and scientists have been paying attention to the fatigue fracture more than 140 years is still one the most important topics in material science. Nowadays, fatigue damage under multiaxial condition is studied predominantly in the case of metallic materials. Also, considerable emphasis is now placed on non-metallic materials, whereas fatigue degradation of these materials has not been studied in the past, see Socie and Marquis (2000) or Schijve (2003). Because, the fracture surface can be considered to be record of the course of degradation process, we can get a lot of information from it. The general availability of the SEM opened up new ways toward the understanding 1st Virtual European Conference on Fracture Utilization normal vectors for description of fracture surfaces Stepan Major a, * a Department of Technical Subject, Faculty of Education - Campus S, Faculty of Science, Hradecká 1285, University Hradec Králové, Hradec Králové 50003, Czech Republic. 1st Virtual European Conference on Fracture Utilization normal vectors for description of fracture surfaces Stepan Major a, * a Department of Technica Subj ct, Faculty o Education - Campus S, Faculty o Science, Hradecká 1285, University Hradec Králové, Hradec Králové 50003, Czech Republic.

* Corresponding author. Tel.: +420; fax: +0-000-000-0000 . E-mail address: author@institute.xxx s.major@seznam.cz, stepan.major@uhk.cz

2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo 10.1016/j.prostr.2020.10.066 2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo 2452-3216 © 2020 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 European Structural Integrity Society (ESIS) ExCo * Corresponding author. Tel.: +420; fax: +0-000-000-0000 . E-mail address: author@institute.xxx s.major@seznam.cz, stepan.major@uhk.cz