New findings on shear thickening fluids

New findings on shear thickening fluids (STFs) at Raman Research Institute (RRI) are touted to have implications for applications ranging from the automobile industry to space technology.

According to a release, a class of dense particulate suspensions, known as STFs, transform under stress from a liquid-like state to a solid-like shear jammed (SJ) state. This has led to their use in the design of smart shock absorbers and liquid-based flexible body-armours.

“STFs have gained attention for their potential use in the material design and development of smart or self-adjusting shock absorbers with flexible mechanical impact-resistant systems in the automobile industry, stabilising lithium-ion batteries, space technology, and the development of protective fabrics by improving the resistance of textile materials against ballistic impact and penetration,” the release added. ‘

Sayantan Majumdar, an Associate Professor in the soft condensed matter research theme at RRI - an autonomous institution funded by the Department of Science and Technology, Governmerrt of India, and his PhD student Sachidananda Barik, have produced the first study that experimentally correlates the microscopic particle-scale dynamics with the bulk relaxation of these materials, the release said.

“Such insight can enable STFs to be tuned to have the precise response required for specific applications. There have been detailed studies of dense particulate suspensions that show a stress induced transformation from a liquid-like state to a solid-like shear jammed state. Despite these detailed studies, the role of microscopic particle scale dynamics in controlling the bulk relaxation of SJ state had not been understood,” the release explained, adding that the study at RRI directly correlates localised failure or plasticity and large-scale particle rearrangement in the system with the time scales associated with the bulk relaxation dynamics.

This study has clearly identified two distinct transient stress relaxation regimes in SJ dense suspensions: a fast relaxation originating from the dynamics of localised plasticity and a much slower one resulting from large-scale, system spanning particle rearrangement. It underscores the importance of local plasticity in controlling the mechanical behaviour of SJ systems, particularly, under high stress condition, the release said.

The findings of the study have been published in Physical Review Letters, the flagship publication of the American Physical Society.

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Printable version | Aug 6, 2022 8:46:06 am |