2022-04-06 08:00:00
A combination of low density and high strength make boron carbide a desirable material for protection applications. However, the ballistic performance of hot-pressed boron carbide is affected by its susceptibility to amorphization beyond the Hugoniot elastic limit (HEL) and by the presence of processing-induced…
Most brittle solids of engineering and scientific interest have stochastic microstructures—comprised of a polycrystalline matrix randomly interspersed with micro-scale defects such as cracks, second-phases, precipitates, grain boundaries, and pores. These defects are often initiators of micro-cracking which results in damage-induced softening and non-linearity in…
Most brittle solids of engineering and scientific interest have heterogeneous microstructures— comprised of a polycrystalline matrix interspersed with micro-scale defects such as cracks, second-phases, precipitates, grain boundaries, and pores. These heterogeneities (“defects”) are often initiators of micro-cracking which results in damage-induced softening and non-linearity…
A machine learning-based constitutive model is proposed to capture the strain rate-dependent, nonlinear stress-strain response of soft materials. This model employs two Gaussian process regression (GPR) models to discover the complex constitutive relationships between stress, strain, and strain rate in the material. Specifically, the…
Understanding dislocation mobility is key to understanding material strength: how materials deform and the energy required to do so. An important unsolved question in this regard is whether dislocations can accelerate to supersonic speeds in metals. Previous molecular dynamics (MD) simulations in cubic crystals…
Normal (NPI) and/or combined Pressure-shear (PSPI) plate impact experiments are often employed for studying the macroscopic response of polycrystalline metals under dynamic loading. However, even for high symmetry metals such as Aluminum, their single-crystalline response is inherently anisotropic leading to significant uncertainty in dynamic…
We explore the impact fragmentation of armor-grade boron carbide cylindrical targets using spherical tungsten carbide projectiles at impact velocities spanning from 100 to 550 m/s. In situ radiography of the target captures the target’s failure history under ballistic loading, while postmortem X-ray-computed tomography scans…
Rate dependent, micro-structured mechanical metamaterials have been engineered to have a wide band of attenuated transmission over a desired frequency range. Enhancing the performance of these structures (by widening the attenuation band or decreasing transmitted energy within that band) can be achieved by layering…
Inertial microcavitation, the formation and collapse of micron to millimeter-sized bubbles, is a widely found phenomenon across engineering and life sciences. Examples include cancer ablation therapies using focused ultrasound histotripsy procedures or spontaneous formation in ballistic, blast, or directed energy events. Within these various…
Measuring and understanding the dynamic failure mechanisms of materials based on microstructural observations is paramount in our effort to design materials from the ground up with predictive and tailored properties. This necessitates the use of reliable high-throughput material testing systems and methods. Herein we…
