3D optical diagnostics for explosively driven deformation and fragmentation

• Published in: International journal of impact engineering 2022-04, Vol.162, p.104142, Article 104142
• Main Authors: Guildenbecher, Daniel R., Jones, Elizabeth M.C., Hall, Elise M., Reu, Phillip L., Miller, Timothy J., Perez, Francisco, Thompson, Andrew D., Ball, James Patrick
• Format: Article
• Language: English
• Subjects: Detonation; Detonators; Digital image correlation; Digital imaging; Exploding bridge-wire detonator; Explosive fragmentation; Fragmentation; Optical diagnostics; Spatial resolution; Trajectory measurement
• ISSN: 0734-743X; 1879-3509
• DOI: 10.1016/j.ijimpeng.2021.104142

•Explosive case deformation and fragmentation quantified by non‐contact, optical diagnostics.•3D case velocity, strain, and strain rates measured with digital image correlation (DIC).•In‐flight fragment velocity and mass quantified via stereo imaging with view normal correction.•Measurement uncertainties and confidence bounds contribute to a validation quality dataset.•Case dynamics and fragment masses show favorable agreement to hydrocode predictions. High-speed, optical imaging diagnostics are presented for three-dimensional (3D) quantification of explosively driven metal fragmentation. At early times after detonation, Digital Image Correlation (DIC) provides non-contact measures of 3D case velocities, strains, and strain rates, while a proposed stereo imaging configuration quantifies in-flight fragment masses and velocities at later times. Experiments are performed using commercially obtained RP-80 detonators from Teledyne RISI, which are shown to create a reproducible fragment field at the benchtop scale. DIC measurements are compared with 3D simulations, which have been ‘leveled’ to match the spatial resolution of DIC. Results demonstrate improved ability to identify predicted quantities-of-interest that fall outside of measurement uncertainty and shot-to-shot variability. Similarly, video measures of fragment trajectories and masses allow rapid experimental repetition and provide correlated fragment size-velocity measurements. Measured and simulated fragment mass distributions are shown to agree within confidence bounds, while some statistically meaningful differences are observed between the measured and predicted conditionally averaged fragment velocities. Together these techniques demonstrate new opportunities to improve future model validation.