Person: Davidovitch, Benny
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Associate Professor, Department of Physics, College of Natural Sciences
Last Name
Davidovitch
First Name
Benny
Discipline
Physics
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I am a theoretical physicist in the condensed matter physics group in the Physics Department at the University of Massachusetts, Amherst. My research interests are primarily in the physics of soft matter, and in non-equilibrium physics. In particular, I study mechanisms for pattern formation in elastic membranes (e.g. wrinkling and crumpling), fluids (e.g. capillary waves and shear banding), and solids (e.g. sputtering-induced nanopatterning).
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Now showing 1 - 7 of 7
Publication Smooth Cascade of Wrinkles at the Edge of a Floating Elastic Film(2010-01-01) Huang, J; Davidovitch, B; Santangelo, C; Russell, T; Menon, NAn ultrathin polymer sheet floating on a fluid forms a periodic pattern of parallel wrinkles when subjected to uniaxial compression. The wave number of the wrinkle pattern increases sharply near the fluid meniscus where the translational symmetry of this one-dimensional corrugated profile is broken. We show that the observed multiscale morphology is controlled by a new “softness” number that quantifies the relative strength of capillary forces at the edge and the rigidity of the bulk pattern. We discover a new elastic cascade by which the wrinkling pattern in the bulk is smoothly matched to the fine structure at the edge by a discrete series of higher Fourier modes.Publication Far From Threshold Buckling Analysis of Thin Films(2010-01-01) Davidovitch, B; Schroll, RThin films buckle easily and form wrinkled states in regions of well defined size. The extent of a wrinkled region is typically assumed to reflect the zone of in-plane compressive stresses prior to buckling, but recent experiments on ultrathin sheets have shown that wrinkling patterns are signif- icantly longer and follow different scaling laws than those predicted by standard buckling theory. Here we focus on a simple setup to show the striking differences between near-threshold buckling and the analysis of wrinkle patterns in very thin films, which are typically far from threshold.Publication Elastic building blocks for confined sheets(2010-01-01) Schroll, R; Katifori,; Davidovitch, BWe study the behavior of thin elastic sheets that are bent and strained under the influence of weak, smooth confinement. We show that the emerging shapes exhibit the coexistence of two types of domains that differ in their characteristic stress distributions and energies, and reflect different constraints. A focused-stress patch is subject to a geometric, piecewise-inextensibility constraint, whereas a diffuse-stress region is characterized by a mechanical constraint - the dominance of a single component of the stress tensor. We discuss the implications of our findings for the analysis of elastic sheets that are subject to various types of forcing.Publication Overview(2017-01-01) Davidovitch, Benjamin; Menon, Narayanan; Welborn, Jennifer; Kermenski, WaynePublication Patterns Around Us Presentation(2016-01-01) Davidovitch, BennyPublication On the stabilization of ion sputtered surfaces(2007-01-01) Davidovitch, BThe classical theory of ion beam sputtering predicts the instability of a flat surface to uniform ion irradiation at any incidence angle. We relax the assumption of the classical theory that the average surface erosion rate is determined by a Gaussian response function representing the effect of the collision cascade, and consider the surface dynamics for other physically motivated response functions. We show that although instability of flat surfaces at any beam angle results from all Gaussian and a wide class of non-Gaussian erosive response functions, there exist classes of modifications to the response that can have a dramatic effect. In contrast to the classical theory, these types of response render the flat surface linearly stable, while imperceptibly modifying the predicted sputter yield vs incidence angle. We discuss the possibility that such corrections underlie recent reports of a “window of stability” of ion-bombarded surfaces at a range of beam angles for certain ion and surface types, and describe some characteristic aspects of pattern evolution near the transition from unstable to stable dynamics. We point out that careful analysis of the transition regime may provide valuable tests for the consistency of any theory of pattern formation on ion sputtered surfaces.Publication Period fissioning and other instabilities of stressed elastic membranes(2009-01-01) Davidovitch, BWe study the shapes of elastic membranes under the simultaneous exertion of tensile and compressive forces when the translational symmetry along the tension direction is broken. We predict a multitude of morphological phases in various regimes of a two-dimensional parameter space (ϵ,ν) that defines the relevant mechanical and geometrical conditions. These parameters are, respectively, the ratio between compression and tension, and the wavelength contrast along the tension direction. The predicted patterns emerge through new transition and instability mechanisms and include several types of irregular and smooth cascades composed of wrinkles and sharp folds. In particular, the hierarchical morphology predicted under high tension and large wavelength contrast (ϵ⪡1,ν⪢1), explains recent experimental observations on ultrathin membranes floating on liquid.