Mechanical Behavior and Fracture of Fibrous Materials at Large Deformations Angelos Gkarsen Dagklis

Format:

Book

Thesis/Dissertation

Author/Creator:

Gkarsen Dagklis, Angelos, author.

Contributor:

University of Pennsylvania. Mechanical Engineering and Applied Mechanics., degree granting institution.

Language:

English

Subjects (All):

0548.

0648.

0786.

0791.

0794.

Local Subjects:

0548.

0648.

0786.

0791.

0794.

Physical Description:

1 electronic resource (148 pages)

Contained In:

Dissertations Abstracts International 87-07B

Place of Publication:

Ann Arbor : ProQuest Dissertations and Theses, 2025

Language Note:

English

Summary:

A crosslinked fiber network microstructure is a common pattern among numerous synthetic and biological materials. The mechanical behavior of network materials is characterized by large deformations before failure and a strain-stiffening stress-strain response. In this thesis, discrete network simulations at the microstructural level, along with theoretical and computational results from continuum models are used to study the mechanical behavior and fracture of network materials.In Chapter 2, local Cauchy and first Piola-Kirchhoff stress tensors for discrete networks of central-force elements are defined based on the equivalence of virtual power between the discrete system and its continuum representation. The framework is rigorously validated by demonstrating that non-uniform stress fields computed in discrete simulations of networks with defects show excellent agreement with continuum predictions for problems involving both infinitesimal and large, non-linear deformations. This definition provides a robust tool for interpreting micromechanical simulations in a physically consistent continuum sense, enabling the study of complex problems involving stress concentrations and material heterogeneity. Network materials are reported to resist fracture in the presence of cracks, and this property is related to their nonlinear behavior. A discrete fiber network computational model for the microstructure of network materials is developed in Chapter 3 to study the effects of a sharp crack under very large deformations. We compute the stress fields near the crack tip in the discrete simulations, and the discrete results are compared to predictions The computed stress field from the discrete network reproduces continuum solutions from asymptotic analysis using nonlinear fracture mechanics. The dominant stress components as a function of the undeformed distance from the crack follow a singular relation predicted from the asymptotic analysis. The scaling exponent is determined completely by the constitutive behavior of individual fibers, effectively relating the macroscopic continuum behavior directly to the microstructure. Furthermore, a scaling law relating the macroscopic rupture stretch of a specimen to the crack length is derived from nonlinear asymptotic analysis and verified computationally. The scaling exponent is also determined completely by the fiber constitutive behavior, and it suggests that the rupture stretch has a weaker dependence on crack length for strain-stiffening non-linear networks, which is a potential explanation for the crack insensitivity of this class of materials. A multiscale approach, which combines discrete particle-based simulations and large-deformation continuum mechanics, is developed in Chapter 4 to explore the mechanobiology, damage and fracture of fibrin networks. A continuum model that predicts macroscopic behavior for arbitrary states of deformation, including damage evolution, is constructed from mesoscopic simulations. The continuum model can access length- and time-scales that are inaccessible in discrete simulations, which allows prediction of fracture toughness, the material property that determines rupture resistance in the presence of defects

Notes:

Advisors: Bassani, John L.; Purohit, Prashant K. Committee members: Ponte Castaneda, Pedro; Tertuliano, Ottman A.

Source: Dissertations Abstracts International, Volume: 87-07, Section: B.

Ph.D. University of Pennsylvania 2025

Vendor supplied data

Local Notes:

School code: 0175

ISBN:

9798276001975

Access Restriction:

Restricted for use by site license