Purdue University Graduate School
Thesis Document_Ankit Agarwal.pdf (91.5 MB)

Particle Mechanics and Continuum Approaches to Modeling Permanent Deformations in Confined Particulate Systems

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posted on 2020-07-28, 18:42 authored by Ankit AgarwalAnkit Agarwal
The research presented in this work addresses open questions regarding (i) the fundamental understanding of powder compaction, and (ii) the complex mechanical response of particle-binder composites under large deformations. This work thus benefits a broad range of industries, from the pharmaceutical industry and its recent efforts on continuous manufacturing of solid tablets, to the defense and energy industries and the recurrent need to predict the performance of energetic materials. Powder compacts and particle-binder composites are essentially confined particulate systems with significant heterogeneity at the meso (particle) scale. While particle mechanics strategies for modeling evolution of mesoscale microstructure during powder compaction depend on the employed contact formulation to accurately predict macroscopic quantities like punch and die wall pressures, modeling of highly nonlinear, strain-path dependent macroscopic response without a distinctive yield surface, typical of particle-binder composites, requires proper constitutive modeling of these complex deformation mechanisms. Moreover, continued loading of particle-binder composites over their operational life may introduce significant undesirable changes to their microstructure and mechanical properties. These challenges are addressed with a combined effort on theoretical, modeling and experimental fronts, namely, (a) novel contact formulations for elasto-plastic particles under high levels of confinement, (b) a multi-scale experimental procedure for assessing changes in microstructure and mechanical behavior of particle-binder composites due to cyclic loading and time-recovery, and (c) a finite strain nonlinear elastic, endochronic plastic constitutive formulation for particle-binder composites.


National Science Foundation Grant No. CMMI-1538861

US Air Force Research Laboratory Grant No. FA8651-16-0287

US Air Force Research Laboratory Grant No. FA8651-16-D-0287

US Air Force Research Laboratory Grant No. FA8651-17-S-0003


Degree Type

  • Doctor of Philosophy


  • Mechanical Engineering

Campus location

  • West Lafayette

Advisor/Supervisor/Committee Chair

Marcial Gonzalez

Additional Committee Member 2

Carl Wassgren

Additional Committee Member 3

Ganesh Subbarayan

Additional Committee Member 4

Rodrigo Salgado