International Journal of Impact Engineering 35 (2008) 1000–1008
Ballistic impact response of laminated composite panels
, D.S. Cronin
, A. Plumtree
Department of Mechanical Engineering, University of Waterloo, 200 University Ave., W, Waterloo, ON, Canada N2L 3G1
Received 16 October 2006; received in revised form 3 April 2007; accepted 23 July 2007
Available online 8 August 2007
Laminated ballistic composite panels are an important part of hard-plate protective body armour and may be subjected to a wide
variety of impact conditions depending on the projectile, impact velocity and armour construction, to name a few.
The ballistic response of laminated composite panels has been investigated through direct impacts of two non-deforming projectiles
(7.5 mm diameter hardened steel 1201 cylindrical–conical, and 9 mm hemispherical nosed) selected to enhance different failure
mechanisms including penetration and delamination.
Experimental and numerical studies were carried out to determine the ballistic response of laminated Kevlar
29 and 129 composite
panels, commonly used in protective body armour. These panels were impacted at velocities between 130 and 250 m/s, which were below
the penetration limit of the panels.
A numerical parametric study was initially undertaken to determine those material properties which reduce back face signature (BFS;
maximum dynamic displacement), one of the important performance indicators for assessing personal protection. Experimental material
characterization then allowed mechanical property data to be determined for numerical simulations, which showed good agreement with
the experimental data, particularly for the conical projectile impacts on both types of Kevlar
Numerical simulations of the impact tests accurately predicted the BFS and dynamic response for the conical projectile impacts, while
the BFS for the hemispherical projectiles was slightly low. This can be attributed to the dominant delamination failure mechanisms,
which may not be completely captured by the numerical model. Importantly, the numerical analysis accurately predicted the initial
velocity of the panel back face for the hemispherical projectiles and the time to reach maximum BFS for the conical projectiles.
r 2007 Elsevier Ltd. All rights reserved.
Keywords: Back face signature; Ballistic impact; Explicit numerical modelling; Fabric material properties woven; Laminated composites
Laminated ballistic composite materials may be used in
protective helmets, or with ceramics and other materials for
protective body armour. Standard hard plate protective
body armour is made up of multiple layers, commonly
including a ceramic plate to blunt and fracture projectiles
and a laminated composite panel to stop the projectile
while containing the ceramic particles. Armour may
include an anti-trauma layer to reduce potential injury
caused by dynamic deformation of the armour into the
wearer. The maximum displacement of the armour during
impact is described as the back face signature (BFS)  and
is a key measure of ballistic performance.
Two dominant types of composite fabric may be used in
protective body armour, including aramid, speciﬁcally
, and polyethylene-based materials such as Spec-
. Layers of woven or unidirectional
ﬁbres are bonded using a thermoplastic or thermosetting
polymer matrix. The present study has focused on the
ballistic response of K29 and K129 woven Kevlar
(DuPont, USA) fabric (2 Â 2 basket weave, 1500 denier)
laminated using a polyvinyl butyral (PVB)-phenolic matrix
(18% volume fraction).
The design, performance and evaluation of composite
panels undergoing ballistic impact require an understand-
ing of material properties under high impact conditions.
There are several models that describe the impact on woven
composites. However, many deal with low-velocity impacts
ARTICLE IN PRESS
0734-743X/$ - see front matter r 2007 Elsevier Ltd. All rights reserved.
E-mail address: firstname.lastname@example.org (D.S. Cronin).
Now at: Netherlands Institute for Metals Research, Mekelweg 2, P.O.
Box 5008, Delft, The Netherlands.