Structural response of laminated composite plates to blast load F. Dolce*, M. Meo, A. Wright, M. French and M. Bernabei This work deals with three-dimensional numerical simulations of damage caused by air blast on fully clamped rectangular plates. The study examines the performance of both metallic and CFRP laminates subjected to blast loads using commercial LS-DYNA software, including a cohesive damage model to represent delamination. The blast load was simulated using a CONWEP algorithm and MMALE approach with fluid–structure interaction between the Eulerian blast and Lagrangian target models. The simulation results are presented and compared with the experimental data, showing good agreement in terms of dynamic deflection, damage morphology and residual deformation. Keywords: Blast, CFRP, FEM, MMALE, LS-DYNA Introduction As a consequence of different accidental or intentional events, such as terrorist attacks and guerrilla warfare, the behaviour of structural materials under blast load has received considerable attention in recent years. Due to their high specific properties, fibre reinforced poly- mers are being considered for use in a wide range of structural applications where their low weight and resistance to blast loading are of importance, such as armoured fighting vehicle hulls. Modern military vehi- cles are a compromise between the need of a great mobility and the increasing payload request. 1 These fairly opposite design requirements are leading the development of lightweight armoured fighting vehicles and research into lightweight vehicle structures are playing an important role in this process. With the associated request for lighter protection systems, there has been an increasing move towards armour systems which are both structural and protection components at the same time. Fibre reinforced composite materials respond to this demand as an acceptable combination of structural performance and low density. In particular, CFRP composites exhibit excellent specific structural properties and since the costs of experimental trials are usually very high, numerical finite element method (FEM) analysis can be a useful tool to minimise the number of experiments and also to understand general phenomenological aspects. The first works regarding the response of structural components to blast loads concerned homogenous metal beams and plates. 2–11 These were focused on the effect of boundary, load and material properties to understand the physical phenomenon and to classify the failure morphologies. The first studies regarding the effects of blast loads on composite structures concerned the effects of under- water blast shock on fibre reinforced polymer matrix composites. Mouritz and co-workers investigated the effect on the fatigue life, damage, failure and bending properties. 12–14 They showed that glass reinforced plastic panels backed by air and loaded by underwater blast wave at low overpressure exhibit only matrix cracking, while, as load increases, the damage appears in form of fibre failure and delamination. Regarding analytical and numerical works, although modelling of blast impact on structures is quite complex due to the dependence on both load history and boundary condi- tions, a rather wide literature about prediction of structures behaviour under blast load can be found. In the 1990s, Olson and Nurick analysed stiffened and unstiffened clamped square mild steel plates under uniformly distributed blast load. 9,15 In the case of unstiffened plate the non-linear numerical models showed strain rate sensitive plates exhibiting mode I, mode II and a trend towards mode III failure as the load intensity increases. In 2001, Wang 16 presented a bench- mark work of simulation of explosion in soil and air using LS-DYNA commercial code and Eulerian for- mulation. From this report it appears that for a landmine explosion simulation results are in a satisfac- tory agreement with experiments. Although the pre- dicted pressure is in certain cases 50% greater than the measured one, the author showed how this overpressure decreases as the Eulerian mesh size decreases. Blast test description Blast tests were performed at a stand-off distance of 150 mm in order to apply the load in the centre of the plate and to reduce boundary effects. The targets were 800 mm by 800 mm square and were clamped in position using a purpose built test rig and a spherical explosive charge supported as shown in Fig. 1. Flight Test Centre, Italian Air Force, Pratica di Mare, Rome, Italy *Corresponding author, email ferdinando.dolce@aeronautica.difesa.it 180 ß Institute of Materials, Minerals and Mining 2010 Published by Maney on behalf of the Institute Received 11 September 2009; accepted 28 September 2009 DOI 10.1179/174328910X12608851832858 Plastics, Rubber and Composites 2010 VOL 39 NO 3/4/5