Failure mode transition in air-backed plates from near contact underwater explosions

Article type: Research Article

Authors: Riley, Mark J. | Paulgaard, Geoffrey T. | Lee, Julian J. | Smith, Malcolm J.

Affiliations: Defence Research and Development Canada – Atlantic, 9 Grove St., Dartmouth, N.S., Canada | Amtech Aeronautical Ltd, Medicine Hat, AB, Canda | Defence Research and Development Canada – Suffield, Suffield, AB, Canada

Note: [] Corresponding author. Tel.: +1 902 426 3100 Ext. 358; Fax: +1 902 426 9654; E-mail: [email protected]

Abstract: Recent experiments involving near-contact underwater explosions on air-backed plates suggest the following failure mode categories: (1) holing and petaling, (2) complete or partial edge tearing due to shock only, (3) complete or partial edge tearing due to shock and bubble collapse, and (4) large deformation without rupture. Finite-element analysis was used to further investigate the detailed response and failure of the plates, and determine the limit between center plate holing and edge failure. When compared with experimental results, finite-elements showed good agreement with the failure modes of the plates and reasonable agreement with the experimental deformations. It was found that the linear interaction criteria (LIC) failure between plastic strain and through-thickness shear stress produced results closer to experiments than the quadratic interaction criteria (QIC). For the 18~gauge specimens it was found that the through-thickness shear dominated the failure initiation for very close proximity charges, with the direct strain becoming dominant as the standoff was increased. For the thinner 20 and 22 gauge plates the direct strain was always found to be the dominant factor in the failure criteria.

Keywords: Underwater explosions, shock, petaling, fluid-structure interaction, finite element analysis, marine structures, material failure

DOI: 10.3233/SAV-2010-0517

Journal: Shock and Vibration, vol. 17, no. 6, pp. 723-739, 2010