Experimental Investigations on Microshock Waves and Contact Surfaces

Programmable focused laser differential interferometer with a spatial light modulator as a dynamic diffractive optical element

A spatial light modulator (SLM) is incorporated into a focused laser differential interferometer (FLDI) to generate a nonlinear array of beams, and this setup is used to measure the power spectral density of a Mach-1.5, underexpanded jet of air. The results are compared with measurements from a 1-point FLDI to assess the feasibility of using SLMs in FLDI to serve as dynamic diffractive elements for generating beam arrays of any shape. The spectra comparison illustrates that spatial light modulated-FLDI (SLM-FLDI) detects similar spectral profiles to that of 1-point FLDI, especially dominant frequencies in the jet. SLM-FLDI could provide a useful expansion of FLDI capabilities.

Surface Interactions of Transonic Shock Waves with Graphene-Like Nanoribbons

Graphene-like nanoribbons (GLNRs) were fabricated (length—20 μm; width—2 μm) and subjected to blast-like pulsed pressure >1.5 GPa (pulse speed ≈1 Mach, impulse duration, ≈µs) to examine the amount of absorption. GLNRs prepared by the chemical vapor deposition technique via controlled biomass combustion were subjected to investigate the structure–property characteristics using microspectroscopic techniques. Following this, GLNRs were employed to high strain rate (HSR) studies with the help of the technique known as split Hopkinson pressure bar (SHPB) to evaluate numerous dynamic parameters. The parameters were extracted from variations in the stress and strain rates. Their analysis provided insight into the damping response of blast energy within GLNRs. By and large, the impact generated modified the microstructure, exhibiting modifications in the number of layers, conjugated loops, and dynamic disorder. Signal processing analysis carried out for incident and transmitted impulse pressure revealed an interaction mechanism of shock wave with GLNR. Details are presented.