Morphological characterization of shocked porous material

TL;DR

This paper introduces morphological measures to analyze the complex shock wave reactions in porous materials, revealing their relation to thermodynamical properties and providing insights into wave dynamics under various conditions.

Contribution

It presents a novel application of morphological measures to characterize shock wave effects on porous materials, linking geometry and topology to thermodynamical behavior.

Findings

Shock waves cause complex sequences of compression and rarefaction.

The fractional white area rate correlates with shock wave velocity.

Area evolution depends on porosity, shock strength, and temperature thresholds.

Abstract

Morphological measures are introduced to probe the complex procedure of shock wave reaction on porous material. They characterize the geometry and topology of the pixelized map of a state variable like the temperature. Relevance of them to thermodynamical properties of material is revealed and various experimental conditions are simulated. Numerical results indicate that, the shock wave reaction results in a complicated sequence of compressions and rarefactions in porous material. The increasing rate of the total fractional white area $A$ roughly gives the velocity $D$ of a compressive-wave-series. When a velocity $D$ is mentioned, the corresponding threshold contour-level of the state variable, like the temperature, should also be stated. When the threshold contour-level increases, $D$ becomes smaller. The area $A$ increases parabolically with time $t$ during the initial period. The $A(t)$ curve goes back to be linear in the following three cases: (i) when the porosity $\delta$ approaches 1, (ii) when the initial shock becomes stronger, (iii) when the contour-level approaches the minimum value of the state variable. The area with high-temperature may continue to increase even after the early compressive-waves have arrived at the downstream free surface and some rarefactive-waves have come back into the target body. In the case of energetic material ... (see the full text)