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SEMINAR – Experimental and Computational Mechanics of Nonwovens
January 19, 2018 @ 10:00 am - 11:00 am
Nonwovens are ubiquitous in both industrial and commercial applications due to their characteristic high surface area, high porosity, damage tolerance, low cost, and the multiplicity of options for tailoring their properties. However, the properties are challenging to predict from a microstructural basis due to the irregular, ill defined, and evolving structure. In particular it is difficult to make a priori designs for strength and toughness. In this talk I will present my group’s work towards understanding the micromechanics of nonwovens under mechanical deformation and how these determine strength and toughness. Our experiments were performed on a set of commercial polypropylene melt-spun nonwovens, which we take as representative of single component nonwovens formed from long fibers and bonded at fiber-fiber contacts. Using a custom setup built at the Cornell High Energy Synchrotron Source, we imaged the microstructural evolution during uniaxial mechanical testing with x-ray scattering, micro computed tomography, and digital image correlation and correlated these mechanisms with relative density. We then developed a combined experimental and computational approach to determine the bond strength distribution within the nonwoven. Finally, I will present a preliminary version of our constitutive model that incorporates all the experimentally measured micro-mechanisms. This model highlights how fiber alignment, fiber plasticity, and bond damage all contribute differently to determine the nonwoven strength depending on the initial specific density of the material.
Meredith Silberstein is an Assistant Professor and Mills Family Faculty Fellow in the Sibley School of Mechanical & Aerospace Engineering at Cornell University. She received her PhD in June 2011 from the MIT Department of Mechanical Engineering with a major in solid mechanics and a minor in energy. Afterward, she served as a postdoctoral fellow at the Beckman Institute at the University of Illinois Urbana-Champaign, investigating mechanochemically active materials. In 2013 she received the Haythornthwaite Research Initiation Grant from ASME Applied Mechanics Division. In 2017 she received the NSF CAREER award. Meredith Silberstein’s Mechanics for Materials Design (MMD) Lab is devoted to using mechanical experiments and modeling methods in material design, with particular focus on multifunctional, active, and polymeric materials.