Center for Composite Materials - University of Delaware

Research Summary

Modeling Nonlinear Conduction Mechanisms of Carbon Composites with Resistor Network

Authors: Hong Yu, Suresh Advani, Dirk Heider

Research Goal

To understand the fundamental conduction mechanisms of carbon composites and implement a model predicting the electrical resistivity of carbon composites under various conditions.

Electrical Conduction Mechanisms of CFRP

• Fiber length direction: Resistivity governed by fiber resistivity and volume fraction
• In-plane transverse: Fiber angulation provides contact between adjacent fibers; resistivity governed by distance between contacts and contact resistance at each contact point
• Through-thickness direction: Fiber angulation and inter-ply connection.

3D Microstructure-Based Model

• 3D structure is generated from combining 2D fiber arrangement with fiber waviness.
• 2D cross-section configuration is generated by assuming hexagonal, square, random packing or from micrograph.
• Fiber waviness adds the 3rd dimension to this microstructure model

Thermal Analysis Using Resistor Network

Coupling of Electrical and Thermal Model

Electrical and thermal models are tightly coupled:
• Heat source in thermal model comes from Joule heating term in electrical model
• Electrical resistance’s of carbon fiber and resin are updated based on temperature given by thermal model

Future Work

Coupled Electrical-thermal-pyrolysis model: proloysis process can be modeled once the thermal profile is calculated from the thermal resistor network model.

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