In this work a numerical model was developed to predict the behavior of thin woven laminates under high velocity impacts. The material model, implemented in a user subroutine to be used with a commercial FE code, takes into account different failure mechanisms. The inter-lamina failure prediction is achieved by means of the use of cohesive elements. Finally, in order to validate the model, experimental tests were accomplished in a wide range of velocities from 100 to 400 m/s. Residual velocity of the projectile and damaged area of the laminates are compared with the numerical results. Once the model is validated, a further investigation has been made in order to analyze the influence of projectile slenderness on the laminate response.This research was done with the ¯nancial support of the Spanish Ministry of Education under Project reference DPI2010-15123 and of the Region of Madrid and University Carlos III of Madrid under Project reference CCG10-UC3M/DPI-4694

In this work a numerical methodology to predict the behavior of composite unidirectional laminates under high velocity impact is developed. In order to validate the model, experimental results of high velocity impacts of steel sphere against laminate coupons, were accomplished. The residual velocity in case of penetration and the damaged area in the panel are the variables chosen to validate the results obtained in the numerical methodology proposed. Finally an analysis of the influence of the projectile geometry is accomplished. (C) 2013 Elsevier Ltd. All rights reserved

In recent years, vulnerability against high-velocity impact loads has become an increasingly critical issue in the design of composite aerospace structures. The effects of Hydrodynamic Ram (HRAM), a phenomenon that occurs when a high-energy object penetrates a fluid-filled container, are of particular concern in the design of wing fuel tanks for aircraft because it has been identified as one of the important factors in aircraft vulnerability. The projectile transfers its momentum and kinetic energy through the fluid to the surrounding structure, increasing the risk of catastrophic failure. In the present paper, the commercial finite-element code ABAQUS/Explicit has been used to simulate an HRAM event due to the impact of a steel spherical projectile into a water-filled woven CFRP square tube. In order to simulate the fluid-structure interaction, the Coupled Eulerian Lagrangian (CEL) approach is used. Experimental tests which indicate the pressure at different points of the fluid, strains of the walls and cavity evolution for different impact velocities are compared with the numerical results in order to assess the validity and accuracy of CEL technique in reproducing such a complex phenomenon. Also, several numerical impacts at different initial projectile velocities are performed to study its influence in the HRAM phenomenon.This research was done with the fianancial support of the Spanish Ministry of Education under Project reference DPI2010-15123 and of the Region of Madrid and University Carlos III of Madrid under Project reference CCG10-UC3M/DPI-4694. The authors would like also to acknowledge the Center for the Development of Industrial Technology (CDTI) of Spain and to the company AERNNOVA Aerospace for the financial support for this research. We wish to express sincere gratitude to Mr. S. Puerta for his valuable help during the experimental testing

In this work, the process of impact that takes place in a partially filled tank is analyzed, performing a numerical simulation, in order to understand the response of the composite laminated structure. The commercial finite-element code LS-DYNA v.R7 has been used to simulate an Hydrodynamic RAM event created by a steel spherical projectile impacting a partially water-filled woven CFRP square tube using two different approaches (MM-ALE and SPH). The intralaminar and interlaminar damage have been taken into account implementing an user subroutine and by means of a cohesive interaction, respectively. Once the numerical model is validated using available experimental data, the effect of the filling level in the failure of the tank is analyzed in detail taking advantage of the information provided by the numerical model. (C) 2013 Elsevier Ltd. All rights reserved.This research was done with the financial support of the Spanish Ministry of Education under Project reference DPI2010-15123 and of the Region of Madrid and University Carlos III of Madrid under Project reference CCG10-UC3M/DPI-4694