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Study on Intrinsic Influence Law of Specimen Size and Loading Speed on Charpy Impact Test

Charpy impact energy/impact toughness is closely related to external factors such as specimen size. However, when the sample size is small, the linear conversion relationship between the Charpy impact energy of the sub-size and full-size Charpy specimens does not hold; the Charpy impact toughness va...

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Detalles Bibliográficos
Autores principales: Jia, Wang, Pi, Aiguo, Zhao, Zhang, Wang, Shaohong, Wei, Chen, Jie, Zhou, Huang, Fenglei
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9181551/
https://www.ncbi.nlm.nih.gov/pubmed/35683153
http://dx.doi.org/10.3390/ma15113855
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author Jia, Wang
Pi, Aiguo
Zhao, Zhang
Wang, Shaohong
Wei, Chen
Jie, Zhou
Huang, Fenglei
author_facet Jia, Wang
Pi, Aiguo
Zhao, Zhang
Wang, Shaohong
Wei, Chen
Jie, Zhou
Huang, Fenglei
author_sort Jia, Wang
collection PubMed
description Charpy impact energy/impact toughness is closely related to external factors such as specimen size. However, when the sample size is small, the linear conversion relationship between the Charpy impact energy of the sub-size and full-size Charpy specimens does not hold; the Charpy impact toughness varies with the size of the specimen and other factors. This indicates that studying the internal influence of external factors on impact energy or impact toughness is the key to accurately understanding and evaluating the toughness and brittleness of materials. In this paper, the effects of strain rate on the flow behavior and the effects of stress triaxiality on the fracture behavior of 30CrMnSiNi2A high-strength steel were investigated using quasi-static smooth bar and notched bar uniaxial tensile tests and Split Hopkinson Tensile Bar (SHTP). Based on the flow behavior and strain rate dependences of the yield behavior, a modified JC model was established to describe the flow behavior and strain rate behavior. Charpy impact tests were simulated using the modified JC model and JC failure model with the determined parameters. Reasonable agreements between the simulation and experimental results have been achieved, and the validity of the model was proved. According to the simulation results, the impact energy was divided into crack initiation energy, crack stability propagation energy and crack instability propagation energy. On this basis, the effects of striker velocity and specimen width on the energy and characteristic load of each part were studied. The results show that each part of the impact energy has a negligible dependence on the hammer velocity, but there is a significantly different positive linear relationship with the width of the sample. The energy increment of each part also showed an inverse correlation with the increase in the sample width. The findings reveal that the internal mechanism of Charpy impact toughness decreases with the increase in sample width; to a certain extent, it also reveals the internal reason why the linear transformation relationship of Charpy impact energy between sub-size specimens and standard specimens is not established when the specimens are small. The analytical method and results presented in this paper can provide a reference for the study of the dynamic behavior of high-strength steel, the relationship between material properties and sample size, and the elastic–plastic impact dynamic design.
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spelling pubmed-91815512022-06-10 Study on Intrinsic Influence Law of Specimen Size and Loading Speed on Charpy Impact Test Jia, Wang Pi, Aiguo Zhao, Zhang Wang, Shaohong Wei, Chen Jie, Zhou Huang, Fenglei Materials (Basel) Article Charpy impact energy/impact toughness is closely related to external factors such as specimen size. However, when the sample size is small, the linear conversion relationship between the Charpy impact energy of the sub-size and full-size Charpy specimens does not hold; the Charpy impact toughness varies with the size of the specimen and other factors. This indicates that studying the internal influence of external factors on impact energy or impact toughness is the key to accurately understanding and evaluating the toughness and brittleness of materials. In this paper, the effects of strain rate on the flow behavior and the effects of stress triaxiality on the fracture behavior of 30CrMnSiNi2A high-strength steel were investigated using quasi-static smooth bar and notched bar uniaxial tensile tests and Split Hopkinson Tensile Bar (SHTP). Based on the flow behavior and strain rate dependences of the yield behavior, a modified JC model was established to describe the flow behavior and strain rate behavior. Charpy impact tests were simulated using the modified JC model and JC failure model with the determined parameters. Reasonable agreements between the simulation and experimental results have been achieved, and the validity of the model was proved. According to the simulation results, the impact energy was divided into crack initiation energy, crack stability propagation energy and crack instability propagation energy. On this basis, the effects of striker velocity and specimen width on the energy and characteristic load of each part were studied. The results show that each part of the impact energy has a negligible dependence on the hammer velocity, but there is a significantly different positive linear relationship with the width of the sample. The energy increment of each part also showed an inverse correlation with the increase in the sample width. The findings reveal that the internal mechanism of Charpy impact toughness decreases with the increase in sample width; to a certain extent, it also reveals the internal reason why the linear transformation relationship of Charpy impact energy between sub-size specimens and standard specimens is not established when the specimens are small. The analytical method and results presented in this paper can provide a reference for the study of the dynamic behavior of high-strength steel, the relationship between material properties and sample size, and the elastic–plastic impact dynamic design. MDPI 2022-05-28 /pmc/articles/PMC9181551/ /pubmed/35683153 http://dx.doi.org/10.3390/ma15113855 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Jia, Wang
Pi, Aiguo
Zhao, Zhang
Wang, Shaohong
Wei, Chen
Jie, Zhou
Huang, Fenglei
Study on Intrinsic Influence Law of Specimen Size and Loading Speed on Charpy Impact Test
title Study on Intrinsic Influence Law of Specimen Size and Loading Speed on Charpy Impact Test
title_full Study on Intrinsic Influence Law of Specimen Size and Loading Speed on Charpy Impact Test
title_fullStr Study on Intrinsic Influence Law of Specimen Size and Loading Speed on Charpy Impact Test
title_full_unstemmed Study on Intrinsic Influence Law of Specimen Size and Loading Speed on Charpy Impact Test
title_short Study on Intrinsic Influence Law of Specimen Size and Loading Speed on Charpy Impact Test
title_sort study on intrinsic influence law of specimen size and loading speed on charpy impact test
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9181551/
https://www.ncbi.nlm.nih.gov/pubmed/35683153
http://dx.doi.org/10.3390/ma15113855
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