International Journal of Impact Engineering 25 (2001) 493}506
Linear elastic shock response of plane plates subjected to
underwater explosion
R. Rajendran, K. Narasimhan*
Naval Science & Technological Laboratory, Visakhapatnam 530 027, India
Department ofMetallurgical Engineering and Materials Science, Indian Institute ofTechnology, Bombay 400 076, India
Received 7 January 1998; received in revised form 16 September 2000; accepted 28 September 2000
Abstract
Linear elastic shock response of plane plates subjected to underwater explosion is of importance to
warship designers. Underwater explosion experiments were carried out with small quantity of explosive
charges on air-backed 4 mm high strength low alloy (HSLA) steel circular plates of 290 mm diameter and
rectangular plates of 300;250 mm with varying stand o!. Strain gauges were "xed at regular intervals from
the centre to the edge of the plates and dynamic strains were recorded. Strain distribution function was
formed from the experimental data using which semi-analytical models were derived for predicting the elastic
strain. The models showed good agreement with the experiments. 2001 Elsevier Science Ltd. All rights
reserved.
Keywords: Underwater explosion; Elastic shock response; HSLA steels; Strain analysis
1. Introduction
The e!ect of underwater explosion against a vessel will depend both on the proximity of the
explosion and the way in which the hull is constructed [1]. The quantity of charge required to hole
a single-hulled vessel during contact explosion is relatively small when compared to that of the
non-contact explosion [2]. If the e!ect of the explosive power is small enough or the stand-o! is
large enough during non-contact explosion, all e!ects of hull structure are within its elastic range
and there is no permanent damage. Estimating the elastic stresses developed during non-cata-
strophic attack of mines, depth charges and torpedoes is of interest to warship designers. Under-
water explosion experiments were carried out on air backed circular and rectangular plates with
* Corresponding author. Tel.: 0091-22-576-7630; fax: 0091-22-572-3480.
E-mail address: nara@met.iitb.ernet.in (K. Narasimhan).
0734-743X/01/$ - see front matter 2001 Elsevier Science Ltd. All rights reserved.
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