Shock induced stress measurements in materials are important for designing materials for hypersonic vehicles, accident tolerant nuclear plants, and energetic material based structures. The characterization of mechanical behavior of a material under shock loading requires techniques that can provide nano second resolved information about the stress state of the material at different varied length scales. In this work, a novel micro particle impact Raman microscope setup is used to measure in-situ dynamic stress evolution induced by shock impact from a particle moving at hyper-velocity. The stress measurement is performed based on in-situ time gated mechanical Raman spectroscopy to measure in-situ dynamic stress in a Hydroxyl-terminated polybutadiene (HTPB) sample. The hyper-velocity particle is accelerated by a pulse laser with impact velocities up to 3km/s. The time gated mechanical Raman spectroscopy uses variation in Raman shift as a function of time to obtain stress induced due to impact for varying strain rates. The Raman spectroscopy is performed with the gate width of 100 nanosecond to capture stress-waves during impact and material behavior after the impact.
2021-04-07 08:00:00
