Material Tailoring of Functionally Graded Materials/Structures

Wednesday, September 27, 2017

2:30pm - 3:45pm

107 Surge Building - VT Campus

Dr. Romesh C. Batra
Biomedical Engineering and Mechanics
Virginia Tech

ABSTRACT: A functionally graded material/structure (FGM/S) has material properties smoothly varying in one or more space dimensions that optimize its performance in pre-specified applications.  Examples of nature-inspired FGMs include teeth, bamboo stems, tree branches, rocks and seashells.  By definition, FGMs are inhomogeneous materials with spatially varying material properties (e.g., Young’s modulus).  Mechanicians have been studying such materials since 1950 before the phrase FGM was coined.  FGMs can be fabricated by smoothly varying the volume fractions of constituents, gradually changing either the fiber orientation angle or the fiber volume fraction in fiber-reinforced composites, adjusting the direction of polarization in piezoceramics, and grading the molecular structure for polymeric materials.  Material tailoring (i.e., finding the microstructure or the spatial variation of the volume fraction of constituents) to optimize either the stress distribution or a deformation related quantity (e.g., the stress concentration factor, the fundamental frequency, the failure initiation time, the buckling load) is more challenging than analyzing a direct problem in which an initial-boundary-value problem is solved.  In this lecture, we will briefly review a few material tailoring problems for both linearly and nonlinearly elastic materials and provide their closed-form solutions.

BIOGRAPHY: Romesh. Batra is the Clifton C. Garvin Professor.  Over the last 44 years his research group has published in peer reviewed journals > 420 papers, with approximately 80% having at most 2 authors, that have received nearly 15k citations with an h-index of 64 on (11k and 54 on Scopus).  Accomplishments of his research group have been recognized by his peers in the form of the Alexander von Humboldt Award (1992), Engineering Science Medal (2009), ASME Honorary Membership (2015), ASME Robert Henry Thurston Lecture Award (2016), State Council of Higher Education of Virginia Outstanding Faculty Award (2010), and Virginia Outstanding Scientist Award (2011)., He is Fellow of the AAM, ASME, ASEE, SES and USACM, and co-Founder and an Editor of the journal, Mathematics and Mechanics of Solids.  He has mentored to successful completion 35 Ph.D. students (33 solo), 19 M.Sc. students (17 solo) and 60 Postdoctoral Fellows/visiting scholars (all solo).  He has authored a graduate level textbook, Elements of Continuum Mechanics, AIAA Press, 2006.