Stress wave micro–macro attenuation in ceramic plates made of tiles during ballistic impact

• As the extent of micro attenuation increases, i.e., αC¯ increases, time taken for reaching steady state decreases.
• As αC¯ increases, the farthest distance traveled by the wave front from the point of impact decreases.
• Quantitative data is presented for stress wave attenuation considering both micro and macro attenuation.

Stress wave attenuation studies during ballistic impact are presented for longitudinal tensile waves propagating along the planar direction within a ceramic plate made of hexagonal tiles bonded with an adhesive. When a stress wave reaches an interface between the ceramic tile and the adhesive layer, reflection and transmission of the incident stress wave takes place leading to attenuation of the wave. This is because of impedance mismatch at the ceramic–adhesive and adhesive–ceramic interfaces. This phenomenon is referred to as macro attenuation. Reflection and transmission of the impact induced stress waves would also take place at the interfaces between grains and grain boundaries within the ceramic plate. This would also lead to attenuation of stress waves, and is referred to as micro attenuation. Micro attenuation is modeled using the stress wave attenuation coefficient. Stress wave attenuation studies are carried out based on both micro and macro attenuation. An algorithm is presented for tracking impact induced planar stress waves and predicting their intensities and extent of attenuation. It is observed that stress wave attenuation is significant as the waves propagate within the ceramic plate. A combination of micro and macro attenuation would give the correct estimate of planar stress distribution around the point of impact.