High strain‐rate shear deformation of a polyurethane elastomer subjected to impact loading

Abstract

Experimental techniques have been developed to produce and measure large amplitude one dimensional compression and shear waves in a polyurethane elastomer (Solithane 113). Experimental measurements consisted of time‐resolved compression and shear amplitude measurements at different distances from the impact surface. The data were analyzed to provide compression and shear wave velocities, and the corresponding stress‐stain curves on the microsecond time scale. The ability to measure directly the high stain rate shear response is a new development and has provided interesting results. The shear modulus varies between 3 and 9 kbar for compressive stresses ranging between 2 and 14 kbar. In contrast, shear modulus values inferred from quasi‐static measurements of bulk and Young's modulus under static high pressure are negligible. These comparisons suggest a high rate dependence of shear modulus in the glassy state. The shear strain curves suggest an elastic‐plastic response with yield strengths ranging from 0.12 kbar to 0.25 kbar with increasing compression for the compressive stress range investigated. Results of compression experiments are also presented.

Compression and shear wave measurements to characterize the shocked state in silicon carbide

“…This configuration maximizes the weaker shear wave signal while minimizing the stronger background signal caused by the preceding compression wave. 22 The shear wave profiles obtained in expt. 8 are shown in Fig.…”

“…͑1͔͒. [18][19][20][21][22][23][24] In expt. 6, the peak longitudinal stress was relatively low ͑10.9 GPa, below the HEL͒ and the material response was elastic.…”

“…18. Because details of the experimental approach and methods have been well documented in the literature, [19][20][21][22][23][24][25][26] only a brief summary is presented here. Upon impact, the momentum imparted to the sample can be decomposed into two components: a longitudinal motion along the x 1 axis and a transverse motion parallel to the x 2 -x 3 plane ͑Fig.…”

“…18 Further details about these measurements can be found in earlier publications. [18][19][20][21][22][23][24][25][26] Three types of experimental configurations were used in this study: the EMV gauges were sensitive only to the longitudinal wave ͑denoted as type C experiment͒ in the first configuration, only to the shear wave ͑type S experiment͒ in the second, and to the vector sum of the two ͑type CS ex-periment͒ in the third. The propagation velocity associated with the onset of a wave of interest was determined by measuring the arrival times of the wave at the two gauge locations and knowing the distance between the locations ͑nomi- nally ϳ5 mm͒.…”

“…[20][21][22][23][24][25] Summarized below are the theory and assumptions related to determination of the mean stress response of a shocked material by the use of shear and longitudinal release wave velocities in the compressed state.…”