Influence of the Use of an Additional External Protective Structure on Decreasing the Deformation of the Floor Plate as a Result of the Detonation of an Explosive under a Vehicle Marek Świerczewski 1 a) , Grzegorz Sławiński 1 b) , Piotr Malesa 1) 1 Military University of Technology Department of Mechanics and Applied Computer Science Gen. Witolda Urbanowicza Street 2, 00-908 Warsaw, Poland a) marek.swierczewski@wat.edu.pl b) grzegorz.slawinski@wat.edu.pl Abstract. The article presents the effects of the shock wave on the model of a light wheeled armoured vehicle. The aim of tests was to check the influence of the use of an additional external protective structure on decreasing the deformation of the floor plate occurring as a result of the detonation of an explosive. The explosive has been detonated under the vehicle in accordance with the STANAG 4569 requirements [1,2]. In order to test the effectiveness of the proposed design solution, numerical calculations using the finite element method with the ALE formulation [3] have been conducted. Thanks to such an approach, it was possible to reflect the following processes: deformation, wave propagation, interaction with the structure and the response of the additionally used protective system. INTRODUCTION Current military conflicts in Europe (fights in Eastern Ukraine), in Africa (the war in Somalia) or in Asia (the conflict in Syria) show that heavy weapons such as tanks, howitzers and heavy artillery are being replaced by mobile weapons. Heavy armoured equipment is more and more often replaced by wheeled armoured vehicles which are characterised by high mobility and effectiveness on the battle field. Such a vehicle type is most often characterised by the modular design, thanks to which it is possible to quickly transform one vehicle variant into another one depending on the needs. The fast increase of wheeled armoured vehicles which are used by different armies and their common use in day-to-day patrol actions during stabilisation missions result in the fact that they are exposed to the effects of the majority of enemy’s fire means, including also anti-tank mines and, more and more often, improvised explosive devices (IED). The aim of the paper was to test the influence of the use of an additional external protective structure on decreasing the deformation of the floor plate occurring as a result of the detonation of an explosive under a vehicle. The effects of the shock wave have been tested on a vehicle without and with a protective system. TEST OBJECT The increasing number of wheeled armoured vehicles in stabilisation missions and military conflicts was the reason for choosing this vehicle type to check the effectiveness of the use of an additional protective system. Due to the high cost of experimental test, the paper is limited to numerical calculations in which a simplified model of the light armoured vehicle, presented in Fig. 1a, has been used. In all analysed variants, the detonated explosive has been located towards the vehicle in accordance with Fig. 1b.