Evolution of dynamic shear strength of frictional interfaces during rapid normal stress variations
California Institute of Technology, Department of Aerospace (Galcit), 91125 Pasadena (CA), USA
2 California Institute of Technology, Division of Geological and Planetary Sciences, 91125 Pasadena (CA), USA
3 Ben-Gurion University of the Negev, Department of Earth and Environmental Sciences, 84105 BeerSheva, Israel
4 California Institute of Technology, Division of Engineering and Applied Science, 91125 Pasadena (CA), USA
* Corresponding author: firstname.lastname@example.org
Published online: 9 September 2021
Pressure shear plate impact tests have revealed that when normal stress changes rapidly enough, the frictional shear resistance is no longer proportional to the normal stress but rather evolves with slip gradually. Motivated by these findings, we focus on characterizing the dynamic shear strength of frictional interfaces subject to rapid variations in normal stress. To study this problem, we use laboratory experiments featuring dynamic shear cracks interacting with a free surface and resulting in pronounced and rapid normal stress variations. As dynamic cracks tend to propagate close to the wave speeds of the material, capturing their behavior poses the metrological challenge of resolving displacements on the order of microns over timescales microseconds. Here we present our novel approach to quantify the full-field behavior of dynamic shear ruptures and the evolution of friction during sudden variations in normal stress, based on ultrahighspeed photography (at 1-2 million frames/sec) combined with digital image correlation. Our measurements allow us to capture the evolution of dynamic shear cracks during these short transients and enable us to decode the nature of dynamic friction.
© The Authors, published by EDP Sciences, 2021
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