Dissertation/Thesis Abstract

Nonlinear Rate-Dependent Material Model with Damage and Plasticity from Granular Micromechanics Approach
by Singh, Viraj, Ph.D., University of Kansas, 2014, 208; 3628920
Abstract (Summary)

Cross-linked polymers and soft materials exhibit nonlinear rate and time dependent behavior, predominantly at high stress/strain amplitudes or at elevated temperatures. The existing constitutive relationships in the literature are phenomenological based and ignores the effect of microstructural changes on the overall mechanical behavior. Therefore, to overcome the limitation of phenomenological based models, we utilize granular micromechanics approach in conjunction with thermo-mechanics to develop a physics based constitutive model with included damage and plasticity at micro-scale. To obtain the stress-strain behavior, appropriate micro-scale force displacement relationship is used along with the kinematic assumption and theory of stress means. The advantage of this approach is that, the resultant continuum model retains the discrete nature of underlying material by incorporating the effect of nearest neighbor grain interactions. In addition to this, damage and plastic potential are defined using simple 1d functions at micro-scale.

To demonstrate the capability of the developed model, it is implemented into a finite element and Euler beam framework to predict, (a) the nonlinear bending of dentin adhesive and collagen-adhesive composite beams, (b) the creep, creep-recovery and monotonic behavior of hot mix asphalt (HMA), (c) the durability of adhesive-dentin interface subjected to monotonically increasing load and (d) the permanent deformation of HMA pavement under cyclic load. Numerical results indicate that the model is able to predict accurately (i) the nonlinear bending of dentin adhesive beams under chemically active media, (ii) tertiary creep and creep-time to failure of HMA. In addition to this, FE simulations show that, the strength of a-d interface is affected by both the loading rate and the geometry of a-d interface and the rutting depth of HMA pavement depends nonlinearly upon the applied load

Indexing (document details)
Advisor: Misra, Anil
Commitee: Han, Jie, Kieweg, Sarah L., Laurence, Jennifer S., Spencer, Paulette, Ye, Qiang
School: University of Kansas
Department: Mechanical Engineering
School Location: United States -- Kansas
Source: DAI-B 75/11(E), Dissertation Abstracts International
Subjects: Mechanical engineering
Keywords: Damage-plasticity, Dentin adhesives, Granular materials, Micromechanics, Rate-dependence, Thermomechanics
Publication Number: 3628920
ISBN: 978-1-321-05529-0
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