The thesis presents a combined experimental and computational investigation of a novel thermochemical material removal mechanism for cutting of polycrystalline cubic boron nitride (PCBN) substrates through controlled crack propagation. The CO2-Laser/Waterjet machining system developed by the Iowa State University’s Laboratory for Lasers, MEMS, and Nanotechnology was utilized to achieve specimen...

ABSRACT: Reports of collapses and whumpfing sounds and their links to instability in the snowpack have been around for decades, but like many areas of snow science, they have received limited scientific treatment. There is a consensus that shear fracture plays an important role in the avalanche process, but the role of collapse is disputed. Many field and laboratory measurements show support fo...

Experimental and numerical simulation studies are conducted on a scaled ship side-shell quasi-statically punched at the mid-span by raked bow indenter to investigate its damage characteristics from deformation large opening. A stiffened panel designed in model tests. Numerical is performed simulate indentation responses. The experimental results compared well terms of resistance-penetration cur...

Within the context of seismic wave propagation, fractures can be described as thin layers or linear-slip interfaces. In this paper, numerical simulations of elastic wave propagation in a medium with a single fracture represented by these two models are performed by 2D finite-difference codes: a variable-grid isotropic code for the thin-layer model and a regular-grid anisotropic code for the lin...