Seminars

Porous materials are ubiquitous in both nature and engineering applications. In the latter, porosity may be present by design or induced by either processing or deformation. Understanding how porosity affects mechanical properties is paramount in a variety of applications, even when the material is not sought for structural performance. However, many challenges face the development of experimentally validated constitutive models for porous materials under complex loadings, especially for advanced applications of architected materials and nanoporous metals. The talk discusses from first principles the plasticity of porous materials. Emphasis is laid on unhomogeneous yielding, defined as a percolative process of yielding on a system of bands. A universal feature of all intrinsic yield criteria is their dependence upon the band resolved normal and shear stresses. When specialized to isotropy, strong dependence upon the third stress invariant emerges naturally. The general theory bears some features of crystal plasticity, but with dilatancy. The evolution of microstructural parameters can be given in general terms, being solely based on the kinematic constraints of unhomogeneous yielding and matrix incompressibility. Throughout the talk, the competition with homogeneous yielding, heretofore taken for granted, is analyzed with applications to cellular materials and ductile failure of metals.

Amine Benzerga is the General Dynamics Professor of Aerospace Engineering at Texas A&M University, which he joined in 2004. He holds an engineering diploma from SUP'AERO (Toulouse, 1995) and a Ph.D. in Materials Science and Engineering from Mines de Paris in 2000. Prior to joining Texas A&M, he was a Research Engineer at the National Research Laboratory of Gaz de France (now NG) on leave at Brown University (Providence, USA) where he later pursued his post-doctoral studies in Solid Mechanics. His research interests include the deformation and fracture of structural and functional materials. Dr. Benzerga was the recipient of a CAREER award from NSF in 2008 and the Edward Pete Aldridge Associate Professor of Aerospace Engineering (2011-2014). He is currently the Director of the Center for intelligent Multifunctional Materials and Structures (CiMMS) and holds a joint appointment in the Department of Materials Science and Engineering at Texas A&M.