A study conducted by graduate student Larry Galloway, post-doc Xiaoguang Ma, and faculty members Paulo Arratia, Douglas Jerolmack, and Arjun Yodh, provides new insights about how the microscopic structure (characterized by excess entropy) of disordered solids is related to the external stresses applied and to the resulting shifting motions of individual constituent particles during plastic deformation. The team conducted experiments on a two-dimensional colloidal solid sheared by the motion of small magnetic needle. The shearing force caused the solid to plastically deform, and concurrent video microscopy enabled tracking of the movements 50,000 particles in the solid.
Galloway, K.L., Ma, X., Keim, N.C., Jerolmack, D.J., Yodh, A.G., and Arratia, P.E., Scaling of relaxation and excess entropy in plastically deformed amorphous solids. Proceedings of the National Academy of Sciences, online published May 19, 2020 https://doi.org/10.1073/pnas.2000698117.news release