PSI - Issue 20

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Procedia Structural Integrity 20 (2019) 254–258

1st International Conference on Integrity and Lifetime in Extreme Environment (ILEE-2019) Crack branching in polymers A.A. Alexeev*, K.N. Bolshev, V.A. Ivanov, A.S. Syromyatnikova, A.M. Bolshakov Larionov Institute of the Physical-Technical Problems of the North of SB RAS, 1 Oktyabrskaya str., Yakutsk, 677891, Russian Federation Abstract One of the little-studied problems of modern mechanics and the physics of fracture is the crack branching in materials of a different nature. For its research, an analysis of the criteria and mechanisms for crack branching. The investigations of crack branching in polymers and metals, fractographic investigation of the fracture surface, criteria for crack branching as a dynamic stress intensity factor, crack speed are considered. Experimental studies of crack branching in a brittle polymer, measuring of crack velocity by breaking the conductive strips with rectilinear propagation and branching of the crack have been carried out. A measurement installation was created on the basis of a precision signal converter of resistance thermometers and thermocouples “ Tercon ” connected to a computer. It is established that the crack at branching in brittle polymers reaches the limiting propagation speed 500 – 800 m/s. A hypothesis is proposed for the physical mechanism of crack branching. 1st International Conference on Integrity and Lifetime in Extreme Environment (ILEE-2019) Crack branching in polymers A.A. Alexeev*, K.N. Bolshev, V.A. Ivanov, A.S. Syromyatnikova, A.M. Bolshakov Larionov Institute of the Physical-Technical Problems of the North of SB RAS, 1 Oktyabrskaya str., Yakutsk, 677891, Russian Federation Abstract One of the little-studied problems of modern mechanics and the physics of fracture is the crack branching in materials of a different nature. For its research, an analysis of the criteria and mechanisms for crack branching. The investigations of crack branching in polymers and metals, fractographic investigation of the fracture surface, criteria for crack branching as a d namic stress i tensity factor, crack speed are considered. Experimental studies of crack branching in a brittle polymer, measuring of crack velocity by breaking the conductive strips with rectilinear propagation and branching of the crack have been carried out. A measurement installation was created on the basis of a precision signal converter of resistance thermometers and thermocouples “ Tercon ” connected to a computer. It is established that the crack at branching in brittle polymers reaches the limiting propagation speed 500 – 800 m/s. A hypothesis is proposed for the physical mechanism of crack branching.

© 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers © 2019 The Author(s).Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers © 2019 The Author(s).Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers

Keywords: Crack, branching, speed, polymer, steel. Keywords: Crack, branching, speed, polymer, steel.

1. Introduction One of the little-studied problems of modern fracture mechanics and physics of a solid body is the crack branching, which is observed in materials of different nature: glass, metals, polymers and rocks, etc. Analysis of theoretical and experimental works by Yoffe (1951), Serensen et al. (1970), Finkel (1970), Ravi Chandar and Knauss (1984), Sharon and Fineberg (1996), Bediy (1991), Naimark (2000), Uvarov (2000), Kobayashi (1985) on the study of branching of cracks in materials of different nature shows that the parameter controlling the 1. Introduction One of the little-studied problems of modern fracture mechanics and physics of a solid body is the crack branching, which is observed in materials of different nature: glass, metals, polymers and rocks, etc. Analysis of theoretical and experimental works by Yoffe (1951), Serensen et al. (1970), Finkel (1970), Ravi Chandar and Knauss (1984), Sharon and Fineberg (1996), Bediy (1991), Naimark (2000), Uvarov (2000), Kobayashi (1985) on the study of branching of cracks in materials of different nature shows that the parameter controlling the

2452-3216 © 2019 The Author(s). Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers 2452 3216 © 2019 The Author(s). Publis ed by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers * Correspon ing auth r. Tel.: +7-411-239-0553; fax: +7-411-233-6665. E-mail address: spinor03@gmail.com * Corresponding author. Tel.: +7-411-239-0553; fax: +7-411-233-6665. E-mail address: spinor03@gmail.com

2452-3216 © 2019 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the ILEE-2019 organizers 10.1016/j.prostr.2019.12.148