ECCM16 - 16 TH EUROPEAN CONFERENCE ON COMPOSITE MATERIALS, Seville, Spain, 22-26 June 2014 1 HIGH IMPACT VELOCITY ON MULTI-LAYERED COMPOSITE OF POLYETHER ETHER KETONE AND ALUMINIUM D. García-González a , A. Aynat a , A. Vaz-Romero a , M. Rodríguez-Millán b , A. Arias a* a Department of Continuum Mechanics and Structural Analysis, University Carlos III of Madrid, Avda. de la Universidad 30, 28911 Leganés, Madrid, Spain b Department of Mechanical Engineering, University Carlos III of Madrid, Avda. de la Universidad 30, 28911 Leganés, Madrid, Spain *aariash@ing.uc3m.es Keywords: PEEK polymer, 2024-T3 aluminum, Ti6Al4V titanium alloy, impact behavior Abstract This work presents an experimental and numerical investigation on the perforation behaviour of layered polymer/metal composite. Penetration tests have been conducted on sandwich panels of aluminum 2024-T3 skin and PEEK cores using spherical projectiles. The perforation experiment covered impact velocities in the range 250 m/s to 500 m/s. The initial and residual velocities of the projectile were measured and the ballistic limit velocity obtained for the considered configuration. The impact mechanical behaviour of PEEK core is compared with Ti6Al4V titanium core, for the same areal density of protection. It has been shown high perforation efficiency of PEEK material and a promised application for aeronautical protections. A numerical modeling is presented and validated with experimental data. 1. Introduction Impact and blast threats exist in a wide range of engineering, security and defence sectors. The protection of civil infrastructures and critical industrial facilities are topics of increasing relevance to defence agencies and governments. In the transport industry, energy absorption and crashworthiness are key points in the design process of vehicles, vessels and aircrafts. Development of protective composite structures capable of sustaining an impact keeping the structural integrity is thus one of the main challenges of modern industry. In the design and development of lightweight structural solutions suitable for energy absorption under impact loading, the material selection represents a crucial decision [1]. Moreover, impact on composite metallic plates is a complex and complete problem including dynamic behaviour, fracture, damage, contact and friction. We observe an internal energy which is an irreversible thermodynamic process due to transfer of kinetic energy, dynamic plastic flow, elastic and plastic wave propagation and large plastic deformation at high strain rates inducing thermal softening responsible of instabilities. It has been observed during this kind of projectile-plate impacts that the nose shape of the projectile used changes the energy absorbed, the failure mode and the ballistic limit, which is a decisive variable for optimum design [2]. This process is strongly coupled to hardening, strain rate and temperature of involved material. In recent years, metal-polymer-metal sandwich sheets show a high potential in forming and design to be used in protective structures versus monolithic metal plates [3]. Of all possibilities for designing hybrid systems, three-layered metal-polymer-metal or multi-layer sheets, offer a