Abstract:

Incorporating interfacial damage and thermal residual stresses, an innovative elastoplastic damage micromechanics is proposed to predict the overall mechanical behavior of fiber-reinforced ductile matrix composites. Up to three interfacial damage modes are considered. The Weibull�s probabilistic function is employed to describe the varying probability of progressive partial fiber debonding with size effects. The effective elastic moduli of four-phase composites are derived by a micromechanical formulation. Thermal residual stresses are taken into account through the concept of thermal eigenstrain to study the effect of the manufacturing process-induced residual stresses. Further, explicit exact formulation on the exterior point Eshelby tensor for elliptical fiber is presented to investigate the effects of aspect ratios. In order to characterize the overall transverse elastoplastic damage behavior, an effective yield criterion is derived based on the statistical ensemble-area averaging process and the first-order effects of eigenstrains. Numerical examples will be presented to illustrate the capability of the proposed framework.

Biography:

Professor Ju received his Ph.D. (1986) from UC Berkeley. He is the Chair of the Structural Engineering & Mechanics Program at UCLA, and served as the Department Chair from 1999 to 2002. Professor Ju served as an Associate Editor for the ASME Journal of Engineering Materials & Technology, and for the ASME Journal of Applied Mechanics from 1995 to 2002. He is the Editor of the Intl. Journal of Damage Mechanics, and is an Editorial Board member of the Acta Mechanica (Intl. Journal). Professor Ju has received the 1991 Presidential Young Investigator Award from the NSF and White House, the 1991 Alfred Rheinstein Faculty Award from Princeton University, the 1997 ASCE Walter Huber Civil Engineering Research Award, the 1998 ASME Fellow Election, the 2000 ACI-James-Instruments Award in NDE, the 2006 ASCE Fellow Election, the 2007 USACM Fellow Award, the 2008 ACI Fellow Award, the 2008-2009 Invited Chair Professorship from the University of Paris VI and ENS Cachan (France), the 2008 Publication Award of Merit from the Structural Engineers Association of Illinois, etc. Professor Ju�s publications have been highly cited by the ISI web of science. Professor Ju�s research interests encompass computational mechanics, damage and fracture mechanics, micromechanics and nanomechanics of composites, multiscale material modeling, finite elements, biomechanics, geomechanics, NDE, and durability of cementitious composites.