- Title Information
- Title
- A Variational Mechanics Theory for Modeling the Evolution of Crack Networks in Composite Materials with Brittle Interfaces
- Name:
Personal
- Name Part
- Vijaykumar, Kaushik
- Role
- Role Term:
Text
- creator
- Name:
Personal
- Name Part
- Kesari, Haneesh
- Role
- Role Term:
Text
- Advisor
- Name:
Personal
- Name Part
- Bower, Allan
- Role
- Role Term:
Text
- Reader
- Name:
Personal
- Name Part
- Srivastava, Vikas
- Role
- Role Term:
Text
- Reader
- Name:
Corporate
- Name Part
- Brown University. Engineering: Mechanics of Solids
- Role
- Role Term:
Text
- sponsor
- Origin Information
- Copyright Date
- 2019
- Physical Description
- Extent
- , None p.
- digitalOrigin
- born digital
- Note:
thesis
- Thesis (Ph. D.)--Brown University, 2019
- Genre (aat)
- theses
- Abstract
- Predicting crack patterns and toughness of structural biomaterials (SBs) is a complex problem due to their complicated microstructures. Most SBs are heterogeneous in nature and consist of a ceramic (stiff) phase and an organic (compliant) phase. The organic phase serves as a weak interface between the ceramic phases of the SBs. For example, spicules, which are needle-like structures found in most sponges, are one type of such SBs, where the ceramic phase occupies a volume fraction > 95% of the material. The stiff phase of spicules is arranged in concentric layers that are separated by nanometer-thin layers of compliant phase, which forms the interface. Toughness enhancement in SBs is attributed to various fracture mechanisms such as crack deflection and arrest at the weak interface. Modeling the fracture behavior of such SBs requires a computational fracture technique that can handle intricate crack topological changes without a priori information of the crack path. Regularized variational fracture theory (RVFT) provides a straight forward methodology to simulate the evolution of complex crack patterns. In RVFT, cracks are modeled using a continuous scalar field, termed the damage field, which takes values between zero (intact solid) and unity (fully broken solid). I modified the traditional RVFT to introduce interfaces by varying the fracture toughness of the solid spatially. I studied fracture of two-dimensional (2D) lamellar composites with weak interfaces under three-point bending and found the underlying mechanism for toughness enhancement to be crack deflection, arrest, and re-nucleation. I also performed three-dimensional (3D) simulations of concentric lamellar composites, which mimics the structure of spicules. I revealed that concentric lamellar architecture does not show significant toughness enhancement as compared to planar lamellar architecture. To experimentally study the role of weak interface in toughness enhancement of composites, I designed an architectured composite composed of Polymethyl methacrylate (PMMA) with a complex network of interfaces (composed of weak adhesive) that mimics SBs. I observed crack arrests and deflections during the fracture tests of architectured composites under three-point bending loading conditions. I found that the architectured composites are almost an order of magnitude tougher than monolithic PMMA.
- Subject
- Topic
- Solid Mechanics
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/00933536")
- Topic
- Fracture mechanics
- Subject
- Topic
- phase field model
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/01013446")
- Topic
- Mechanics
- Language
- Language Term (ISO639-2B)
- English
- Record Information
- Record Content Source (marcorg)
- RPB
- Record Creation Date
(encoding="iso8601")
- 20200720
- Access Condition:
rights statement
(href="http://rightsstatements.org/vocab/InC/1.0/")
- In Copyright
- Access Condition:
restriction on access
- All rights reserved. Collection is open to the Brown community for research.
- Type of Resource (primo)
- dissertations