PSI - Issue 25

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

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Procedia Structural Integrity 25 (2020) 214–225

© 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 the VCSI1 organizers © 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 the VCSI1 organizers Keywords: Tensile strength; Brazilian Disc test; Ring test; Circular Semi Ring test; Stress field; Displacement field; Complex Potentials method 1. Introduction Insuperable difficulties in obtaining the tensile strength of brittle materials by means of the uniaxial tension test rendered the development of alternative tests a pressing demand. Carneiro (1943) and Akazawa (1943), independently from each other, introduced, the Brazilian-disc test (BD), providing indirectly the tensile strength of the material in terms of the tensile stress at the center, Ο , of a circular disc under diametral compression (Fig.1a) as: Abstract Analytic formulae for stre ses and displacem ts are provided for the Circular Semi Ring under either c mpression or tens on. T e respective expressions for the ensile strength for both tests are obtaine and compared to existing on . In addition, it is hown that smooth contact between the specimen and the loading device should be pr ferred. The suggested tests seem to remov some drawback of xis ing methods f r obtaining th tensile strength of brittle materials: Fracture is hieved at points wh re the stress field is purely tensile and, also, very low external force is required thus voiding pr mature fracturing at th specimen loading device cont ct region. From he theoretical point of view t e tens on test appe rs to be more advantage us garding the very low fracture load and the fact that the maximum tensile stress is higher in absolute value from the respective compressive one. © 2020 The Authors. Published by Elsevier .V. This is an ope acces article under C BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers Keywords: Tensile strength; Brazilian Disc test; Ring test; Circular Semi Ring test; Stress field; Displacement field; Complex Potentials method 1. Introduction Insuperabl difficulties in obtain ng he tensile trength of brittle materials by means of the uniaxial t nsion test rendered the d velopment of alt rnative tests a pr sing demand. Carneiro (1943) and Akazawa (1943), independently fro each other, introduced, the Brazilian-disc test (BD), providing indi ectly the tensile strength of the material in terms of the tensile stress at the center, Ο , of a circular disc under diametral compression (Fig.1a) as: 1st Virtual Conference on Structural Integrity - VCSI1 Enlightening the role of critical parameters for the determination of the tensile strength by means of the Circular Semi Ring test Ch. F. Markides, M. Stavropoulou, E. D. Pasiou, S. K. Kourkoulis* Department of Mechanics, School of Applied Mathematical and Physical Sciences, National Technical University of Athens, 5 Heroes of Polytechnion Avenue, Theocaris Bld., Zografou Campus, 157 73 Athens, Greece. Abstract Analytic formulae for stresses and displacements are provided for the Circular Semi Ring under either compression or tension. The respective expressions for the tensile strength for both tests are obtained and compared to existing ones. In addition, it is shown that smooth contact between the specimen and the loading device should be preferred. The suggested tests seem to remove some drawbacks of existing methods for obtaining the tensile strength of brittle materials: Fracture is achieved at points where the stress field is purely tensile and, also, very low external force is required thus avoiding premature fracturing at the specimen loading device contact region. From the theoretical point of view the tension test appears to be more advantageous regarding the very low fracture load and the fact that the maximum tensile stress is higher in absolute value from the respective compressive one. 1st Virtual Conference on Structural Integrity - VCSI1 Enlightening the role of critical parameters for the determination of the tensile strength by means of the Circular Semi Ring test Ch. F. Markides, M. Stavropoulou, E. D. Pasiou, S. K. Kourkoulis* Department of Mechanics, School of Applied Mathematical and Physic l Sciences, National Tech ical University of Athens, 5 Heroes of Polytechnion Avenue, Theocaris Bld., Zografou Campus, 157 73 Athens, Greece.

* Corresponding author. Tel.: +30 210 7721263; fax: +30 210 7721302. E-mail address: stakkour@central.ntua.gr * Corresponding author. Tel.: +30 210 7721263; fax: +30 210 7721302. E-mail address: stakkour@central.ntua.gr

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 the VCSI1 organizers 2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an ope access article under t C BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers

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 the VCSI1 organizers 10.1016/j.prostr.2020.04.026