Date of Award

Spring 2015

Document Type

Thesis

First Advisor

Shivakumar, Kunigal

Abstract

Thermal characterization of composite materials plays an important role in engineering design of thermal structures and aerospace systems and automotive, etc. There are limited data on these materials in the literature. In particular, multidirectional thermal characterization needs to be established for polymer matrix composites to determine their working temperatures and thermal conductivities. In unidirectional fiber reinforced composites, thermal conductivities are different in axial and transverse directions of the composite material. The purpose of this research was to determine multidirectional thermal conductivities of IM7-G/8552 unidirectional carbon/epoxy composite laminate and validate the data with micromechanics models and data in the literature for similar materials. IM7-G/8552 unidirectional composite material was fabricated, and two different types of specimens in axial and transverse direction were prepared. Flash Method was used to measure the thermal diffusivity in axial and transverse directions of fiber using the ASTM E-1461 standard. Differential Scanning Calorimeter was used to measure the specific heat of the composite material using the ASTM E-1269 standard. Then thermal conductivity was calculated by multiplying thermal diffusivity, specific heat capacity, and material density. The experiments were performed at emperatures ranging from 20°C to 100°C. The measured test results agreed well with micromechanics model and similar material in literature. Thermal conductivities of IM7/8552 at room temperature were k1= 4.89 W/m°C in axial and k3= 0.58 W/m°C in transverse directions.

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