Protection technologies, security, situational awareness
Multi-layered ceramic armour is currently used for aircraft, helicopter and land vehicle armour protection as well as for body armour. This system associates a high brittle front layer (ceramic) to erode and comminute the projectile, with a ductile backing (metal or composite) which has to catch all the fragments generated during the impact (projectile and ceramic) through plastic and/or viscoelastic deformation. This system is a huge step ahead in increasing the ballistic performance of ballistic protection structures in terms of efficiency and mass gain. Within the framework of the ISL mechanical activities, an important effort has been made in the last years to characterise and model the mechanical behaviour of the materials composing this type of armour (2 DGA PhD thesis, EDACERAMBALL project, French and German government contracts).
One of the main issues with respect to our ceramic armour is the effect of glue on the overall performance of the system. Some authors in the literature claim that glue has a predominant effect on the materials mechanical properties. For this reason, this study would like to focus on the development of glueless multi-layered ceramic armour, using a coupled SPS-RTM approach. This idea originates from a collaboration between the WIWeB laboratory and ISL. The idea is to use the RTM process, well managed by WIWeB, to directly inject an epoxy resin into a ceramic material developed by AMT with the SPS technology. The main problem in this work would be the study of the compatibility between the materials, in order to obtain the best adhesion properties.
This approach could be very interesting for aircraft and helicopter ballistic protection, where the RTM process is widely used to produce the structural part. The epoxy resin that would be used is the RTM-6 from Hexcel, which has been used in the production of the Airbus A400M. The chosen ceramic material is boron carbide, which is well managed by the AMT group and is the best performing material against small-caliber ammunition. The use of this material is particulary interesting for aerospace applications, where saving weight is a key parameter to improve the aircraft performances.
The work would be mainly focused on the following tasks:
- Study of the compatibility between the AMT boron carbide and the RTM-6 epoxy resin. The adhesion between the two materials would be studied and could be improved using different types of fillers. Different grades of the charged polymer should be obtained at the end of this task, in order to provide more possible final solutions.
- Characterisation and modeling of the mechanical behaviour of the different materials composing the ceramic armour.
- Optimisation of the final configuration, taking into account the compatibility of the materials, the adhesion properties, the RTM process and the mechanical properties of the materials.
- Reinforcing the polymer with long fibers, in order to improve its mechanical properties.
- The final solution should be tested against a real ballistic threat and the results should be compared with a commercial reference solution.