PSI - Issue 82

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2026) 000–000 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2026) 000–000

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ScienceDirect

Procedia Structural Integrity 82 (2026) 72–78

© 2026 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 ICSID organizers Abstract Dynamic splitting of brittle solid specimens is studied where each specimen has one or more perforation lines with aligned small scale cracks corresponding to grain in wood materials. Fracture development in the grain direction is experimentally observed using the technique of dynamic photoelasticity in conjunction with a high-speed video camera. As a preliminary study, a brittle polycarbonate rectangular specimen with vertical straight perforation lines consisting of straight small-scale cracks are prepared and an “axe” is inserted at the top of each specimen. Then, each specimen with the “axe” is dropped onto a rigid plate and subjected to vertical impact from bottom. It is found that, at least in the polycarbonate specimen, the “axe” does not split the specimen all at once along the perforation line, but rather fracture (splitting) repeats extending and arresting until the specimen is totally split along the perforation line. © 2026 The Authors. Copy from the contract: 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 ICSID organizers Keywords: Unzipping fracture; Vertical impact; Dynamic splitting; Dynamic fracture along perforation lines 1. Introduction Wooden structures are considered to have low emissions of carbon dioxide from an environmental viewpoint and are therefore being reevaluated. Their number is increasing in many places, and for instance, edge crack behavior of wood fiber polylactic acid (PLA) composite and pure PLA under quasi-static tension (Carlsson and Isaksson, 2018) has been studied. However, although structures can be subjected to strong vertical shock near epicenters on the onset of seismic shaking and peculiar structural failures have been observed (Uenishi, 2024), dynamic fracture behavior of Abstract Dynamic splitting of brittle solid specimens is studied where each specimen has one or more perforation lines with aligned small scale cracks corresponding to grain in wood materials. Fracture development in the grain direction is experimentally observed using the technique of dynamic photoelasticity in conjunction with a high-speed video camera. As a preliminary study, a brittle polycarbonate rectangular specimen with vertical straight perforation lines consisting of straight small-scale cracks are prepared and an “axe” is inserted at the top of each specimen. Then, each specimen with the “axe” is dropped onto a rigid plate and subjected to vertical impact from bottom. It is found that, at least in the polycarbonate specimen, the “axe” does not split the specimen all at once along the perforation line, but rather fracture (splitting) repeats extending and arresting until the specimen is totally split along the perforation line. © 2026 The Authors. Copy from the contract: 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 ICSID organizers Keywords: Unzipping fracture; Vertical impact; Dynamic splitting; Dynamic fracture along perforation lines 1. Introduction Wooden structures are considered to have low emissions of carbon dioxide from an environmental viewpoint and are therefore being reevaluated. Their number is increasing in many places, and for instance, edge crack behavior of wood fiber polylactic acid (PLA) composite and pure PLA under quasi-static tension (Carlsson and Isaksson, 2018) has been studied. However, although structures can be subjected to strong vertical shock near epicenters on the onset of seismic shaking and peculiar structural failures have been observed (Uenishi, 2024), dynamic fracture behavior of 8th International Conference on Structural Integrity and Durability (ICSID2025) Dynamic splitting of a brittle solid with aligned small-scale cracks Koji Uenishi a,b, *, Kanata Sogawa b , Masanao Sekine b 8th International Conference on Structural Integrity and Durability (ICSID2025) Dynamic splitting of a brittle solid with aligned small-scale cracks Koji Uenishi a,b, *, Kanata Sogawa b , Masanao Sekine b a Department of Advanced Energy, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8561, Japan b Department of Aeronautics and Astronautics, The University of Tokyo, 7-3-1 Hongo, Bunkyo 113-8656, Japan a Department of Advanced Energy, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8561, Japan b Department of Aeronautics and Astronautics, The University of Tokyo, 7-3-1 Hongo, Bunkyo 113-8656, Japan

* Corresponding author. Tel.: +81-4-7136-3824; fax: +81-4-7136-3824. E-mail address: uenishi@k.u-tokyo.ac.jp * Corresponding author. Tel.: +81-4-7136-3824; fax: +81-4-7136-3824. E-mail address: uenishi@k.u-tokyo.ac.jp

2452-3216 © 2026 The Authors. Copy from the contract: 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 ICSID organizers 2452-3216 © 2026 The Authors. Copy from the contract: 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 ICSID organizers

2452-3216 © 2026 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 ICSID organizers 10.1016/j.prostr.2026.04.012