The idea to use metamaterials to mitigate mechanical waves is recent and constitutes a technology under development. These materials have a special design, presenting characteristics not found in nature. The interesting feature is a negative effective mass density. This property is achieved by creating in the structure masses linked by springs which act as internal resonators and, as a result, it is observed that metamaterials act as mechanical filters, preventing or reducing the intensity of propagation of mechanical waves that travel in the structure, when the frequency of propagation is close to the resonance frequencies of the internal resonators.
An internal combustion generates a blast wave which acts on a structure as an impulsive effort. This is a basic phenomenon in the shooting of an armament leading to this research that target to investigate the possible application of metamaterials to improve recoil mechanism technology. A recoil mechanism moderates the firing loads on the supporting structure by prolonging the time of resistance to the propellant gas forces. Depending on application of the armament, recoil can be very undesirable. Firstly, carriage mount where the armament is fixed will suffer premature wear. Secondly and more critical, if the armament is mounted onto a vehicle, its dynamics during shooting is completely affected and an accident can be caused when shooting occurs during a critical situation, like a curvilinear path for example.
It is intended to use numerical simulations and experimental validation to verify the behavior of the designed metamaterial under a controlled impulse input. Finite Element Method (FEM) is used to simulate wave propagation through a common material and then through a special designed metamaterial to evaluate how this kind of pulse will be affected by internal resonators. After the simulations, a prototype adequate to validate numerical results will be investigated on a test bench. In a further development the impulse input will be adapted to real measured blast efforts.
Numerical Simulation and Experimental Validation of an Oil Free Scroll Compressor
