Three dimensional full-field velocity measurements in shock compression experiments using stereo digital image correlation

TL;DR

This paper introduces a novel experimental methodology using stereo digital image correlation to measure full-field velocity in shock compression experiments, providing high spatial and temporal resolution validation across different impact configurations.

Contribution

The study presents the first successful application of 3D digital image correlation for full-field velocity measurements in shock compression, validated against traditional laser interferometry.

Findings

Validated DIC measurements against laser interferometry data.

Demonstrated capability in multi-axial loading conditions.

Achieved high spatial and temporal resolution in velocity measurements.

Abstract

Shock compression plate impact experiments conventionally rely on point-wise velocimetry measurements based on laser-based interferometric techniques. This study presents an experimental methodology to measure the free surface full-field particle velocity in shock compression experiments using high-speed imaging and three-dimensional (3D) digital image correlation (DIC). The experimental setup has a temporal resolution of 100 ns with a spatial resolution varying from 90 to 200 $\mu$m/pixel. Experiments were conducted under three different plate impact configurations to measure spatially resolved free surface velocity and validate the experimental technique. First, a normal impact experiment was conducted on polycarbonate to measure the macroscopic full-field normal free surface velocity. Second, an isentropic compression experiment on Y-cut quartz-tungsten carbide assembly is performed to measure the particle velocity for experiments involving ramp compression waves. To explore the capability of the technique in multi-axial loading conditions, a pressure shear plate impact experiment was conducted to measure both the normal and transverse free surface velocities under combined normal and shear loading. The velocities measured in the experiments using digital image correlation are validated against previous data obtained from laser interferometry. Numerical simulations were also performed using established material models to compare and validate the experimental velocity profiles for these different impact configurations. The novel ability of the employed experimental setup to measure full-field free surface velocities with high spatial resolutions in shock compression experiments is demonstrated for the first time in this work.