Finite element modeling of mechanical properties of bone and bioinspired composites with stiff and soft continuous compared to discontinuous phases

Sabet, Fereshteh Alsadat

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https://hdl.handle.net/2142/110520 Copy

Description

Title

Finite element modeling of mechanical properties of bone and bioinspired composites with stiff and soft continuous compared to discontinuous phases

Author(s)

Sabet, Fereshteh Alsadat

Issue Date

2021-04-23

Director of Research (if dissertation) or Advisor (if thesis)

Jasiuk, Iwona

Doctoral Committee Chair(s)

Jasiuk, Iwona

Committee Member(s)

• Kersh, Marianna
• McKittrick, Joanna
• Wagoner-Johnson, Amy

Department of Study

Mechanical Sci & Engineering

Discipline

Theoretical & Applied Mechans

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Bone
• Finite element simulation
• trabecular bone
• composite
• 3D-printing

Abstract

In this dissertation, the aim is to understand better mechanical properties and arrangement of phases in bone as biological composite material and study the effect of the topology of phases on mechanical properties of 3D-printed bio-inspired composites as well as scale and size effects. In the first part of this dissertation, bone is modeled at the mesoscale (trabecular bone) to shed light on which constitutive law can better describe the behavior of bone at this scale. Finite element models were built from micro-computed tomography images of trabecular bone that allow a precise realization of the geometry. The effect of using different plasticity formulations at the tissue level on the overall mechanical behavior was studied as well as the local response. Also, the effect of volume fraction of bone tissue on the mechanical response of trabecular bone was investigated. Simulations of trabecular bone are highly challenging due to its complex structure. Several types of nonlinearities in the problem result in the need for using an explicit solver instead of an implicit solver for some cases. Although both implicit and explicit methods have been used in the literature, a comparative study on both methods' outcomes is of high interest for the bone modeling community. Thus, a comparison of the effect of using implicit and explicit solvers on the results of modeling trabecular bone has been performed. In the second part, the influence of geometrical arrangements of phases on the overall mechanical properties of bio-inspired composites was investigated. Two-phase composites with stiff and soft phases and different phase geometries, including an interpenetrating phase composite with two continuous phases, a matrix-inclusion composite with a continuous and a discontinuous phase, and a discontinuous phase composite where both phases are discontinuous, were studied. These different types of composites were 3D printed using two polymers: VeroClear (stiff) and TangoBlackPlus (soft). Their mechanical performance was studied both experimentally, using compression testing and digital image correlation, and numerically by a finite element analysis. These composite types were also simulated using properties of bone constituents (collagen and hydroxyapatite) to better understand the nanostructure of bone and its mechanical properties. Scale and size effects were also investigated in these composites, and the results from mechanical testing were compared with finite element modeling results.

Graduation Semester

2021-05

Type of Resource

Thesis

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http://hdl.handle.net/2142/110520

Copyright and License Information

Copyright 2021 Fereshteh Alsadat Sabet

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