Shock wave attenuation by thin films

Shock wave attenuation due to the placement of a thin film in the path of a planar shock wave was investigated experimentally using a horizontal shock tube with inner square cross section. A high-speed schlieren visualization together with high-frequency pressure transducers were used to study the particulars of the film breakup process and to measure peak pressure and impulse. The effect of varying film thicknesses and types of film materials (both ductile and brittle) on shock wave attenuation was considered. For the case of a film thickness less than or of the order of magnitude of the shock wave thickness, it was shown that the shock wave attenuation effect is dominated by the film thickness rather than the acoustic impedance. For these film thicknesses, the different types of failure mechanisms for the film (brittle vs ductile) do not affect the strength of the transmitted shock wave.