PSI - Issue 77

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

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 77 (2026) 389–396

© 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 ICSI organizers Abstract The effect of loading velocity on delamination is taken into account in this paper. A multilayered planar load-carrying structural member of circular cross-section is considered. The member is made up of concentric layers, inhomogeneous in thickness. The member has a horizontal and a vertical portion. The latter is rigidly fixed in its vertical end. The internal delamination arm in the member horizontal portion is at a torsion angle that varies linearly with time. Furthermore, the cross-section where the two parts of the structure are connected is at a bending angle that changes linearly with time. As a result of this, the horizontal and vertical portions are subjected to torsion and bending, respectively. The structure behaviour is non-linear elastic. A constitutive law that accounts for the effect of the velocity is applied. The structure material properties are distributed continuously along the thickness of layers. The strain energy release rate (SERR) is derived. Verification is performed by considering the energy balance in the structural member. The effect of different factors and parameters on the delamination is investigated. © 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 ICSI organizers Keywords: Twist; Bending; Multilayered planar structure; Delamination; Circular cross-section 1. Introduction In the age of high tech, the quick advance in different sectors of engineering demands use of modern and efficient structural materials. Meeting the needs of such materials is one of the key challenges for the engineering International Conference on Structural Integrity Twisting and bending of planar members of circular cross-section: a delamination analysis with considering the loading velocity effect Victor Rizov* Department of Technical Mechanics, University of Architecture, Civil Engineering and Geodesy, 1 Chr. Smirnensky blvd., 1046 – Sofia, Bulgaria

* Corresponding author. Tel.: + (359-2) 963 52 45 / 664; fax: + (359-2) 86 56 863. E-mail address: v_rizov_fhe@uacg.bg

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 ICSI 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 ICSI organizers 10.1016/j.prostr.2026.01.050