PSI - Issue 25

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Procedia Structural Integrity 25 (2020) 465–469 Structural Integrity Procedia 00 (2019) 000–000 Structural Integrity Procedia 00 (2019) 000–000

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© 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 Abstract In this work, a failure of the Kuznetsk coal basin sandstone samples subjected to uniaxial compression is simulated with explicit consideration of pore space. A constitutive response of loaded samples is described in the framework of non-linear model based on the circumscribed Drucker-Prager criterion. The continuum damage mechanics is also employed to describe the softening of a material. The numerical simulation is carried out using the finite-di ff erence method. At all other factors being equal, an amount of pores is varied in the range of ≈ 5–25%. The problem of evaluating the uniaxial compressive strength as a function of porosity is addressed. It is shown that the results of modelling satisfactory meet available experimental data. c 2020 The Authors. Published by Elsevier B.V. is is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) r-review lin : Peer-rev ew und r responsibil ty of the VCSI1 organizers. Keywords: numerical simulation; failure; finite-di ff erence method; damage mechanics; uniaxial compression; Drucker-Prager; The problem of evaluating the threshold values of stress, particularly the crack initiation ( σ ci ), damage ( σ cd ), and peak stress ( σ p ), is of great importance for solving specific engineering problems Martin and Chandler (1994); Hoek and Martin (2014); Kong et al. (2018). Methods of acoustic emission (AE), consideration of a complete stress-strain curve, etc. have been employed to find the threshold values. For instance, it was found that first impulses of AE are observed prior to the peak stress Martin and Chandler (1994); Hoek and Martin (2014); Kong et al. (2018). Structural impurities, e.g. pores, inclusions, intrinsically exist in all rocks. They give rise to local stress concentra tion under applied external load prior to the peak stress which is expressed in local damage and AE impulses. Influence of the porosity on the e ff ective mechanical characteristics (uniaxial compressive strength (further referred to as UCS) and Young’s modulus) has been extensively investigated in many works. e.g. Farrokhrouz and Asef (2017); Atapour and Mortazavi (2018); Smolin et al. (2014, 2016, 2019). Regardless of the nature of materials, the UCS and Young’s modulus decrease with an increase in porosity. 1st Virtual Conference on Structural Integrity – VCSI1 Influence of the porosity on the uniaxial compressive strength of sandstone samples Mikhail Eremin a, ∗ a Institute of strength physics and materials science of Siberian branch of Russian academy of sciences, 2 / 4 Akademicheskii Av., Tomsk, 634055, Russia Abstract In this work, a failure of the Kuznetsk coal basin sandstone samples subjected to uniaxial compression is simulated with explicit consideration of pore space. A constitutive response of loaded samples is described in the framework of non-linear model based on the circumscribed Drucker-Prager criterion. The continuum damage mechanics is also employed to describe the softening of a material. The numerical simulation is carried out using the finite-di ff erence method. At all other factors being equal, an amount of pores is varied in the range of ≈ 5–25%. The problem of evaluating the uniaxial compressive strength as a function of porosity is addressed. It is shown that the results of modelling satisfactory meet available experimental data. c 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 line: Peer-review under responsibility of the VCSI1 organizers. Keywords: numerical simulation; failure; finite-di ff erence method; damage mechanics; uniaxial compression; Drucker-Prager; 1. Introduction The problem of evaluating the threshold values of stress, particularly the crack initiation ( σ ci ), damage ( σ cd ), and peak stress ( σ p ), is of great importance for solving specific engineering problems Martin and Chandler (1994); Hoek and Martin (2014); Kong et al. (2018). Methods of acoustic emission (AE), consideration of a complete stress-strain curve, etc. have been employed to find the threshold values. For instance, it was found that first impulses of AE are observed prior to the peak stress Martin and Chandler (1994); Hoek and Martin (2014); Kong et al. (2018). Structural impurities, e.g. pores, inclusions, intrinsically exist in all rocks. They give rise to local stress concentra tion under applied external load prior to the peak stress which is expressed in local damage and AE impulses. Influence of the porosity on the e ff ective mechanical characteristics (uniaxial compressive strength (further referred to as UCS) and Young’s modulus) has been extensively investigated in many works. e.g. Farrokhrouz and Asef (2017); Atapour and Mortazavi (2018); Smolin et al. (2014, 2016, 2019). Regardless of the nature of materials, the UCS and Young’s modulus decrease with an increase in porosity. 1st Virtual Conference on Structural Integrity – VCSI1 Influence of the porosity on the uniaxial compressive strength of sandstone samples Mikhail Eremin a, ∗ a Institute of strength physics and materials science of Siberian branch of Russian academy of sciences, 2 / 4 Akademicheskii Av., Tomsk, 634055, Russia 1. Introduction

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.2020.04.052 ∗ Corresponding author. Tel.: + 7-382-228-6937. E-mail address: eremin@ispms.tsc.ru 2210-7843 c 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 line: Peer-review under responsibility of the VCSI1 organizers. ∗ Corresponding author. Tel.: + 7-382-228-6937. E-mail address: eremin@ispms.tsc.ru 2210-7843 c 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 line: Peer-review under responsibility of the VCSI1 organizers.