Type of Document	Dissertation
Author	Lee, Munki
Author's Email Address	mulee@vt.edu
URN	etd-03232004-203236
Title	Heat Transfer and Consolidation Modeling of Fiber Tow in Fiber Placement
Degree	PhD
Department	Mechanical Engineering
Advisory Committee	Advisor Name Title Sturges, Robert H. Committee Chair Baird, Donald G. Committee Member Deisenroth, Michael P. Committee Member Leo, Donald J. Committee Member Reinholtz, Charles F. Committee Member
Keywords	Fiber Placement Consolidation Temperature Control Modeling Heat Transfer Composite Manufacturing
Date of Defense	2004-03-19
Availability	unrestricted
Abstract New heating techniques are required to better control heat transfer between heating tools and a composite towpreg in the automated fiber placement process. This dissertation suggests new heating techniques with liquid and rigid contact heat sources, and compares them with a widely used gas heat source for the fiber placement process. A thin towpreg composite model needs to be developed to describe the heat transfer. Subsequently, the response of the towpreg with each heat source was compared from manufacturing speed and energy efficiency viewpoints. The most promising heat source was developed for heat transfer modeling between a moving towpreg and dynamic heat source in the automated fiber placement. Through the heat transfer model, both the temperature controllability of the towpreg and manufacturing speed could be investigated. In addition, an accurate compaction process is needed in response to the growing demand for better composite processing. Since the errors in compaction mechanisms and robotic machinery in fiber placement have not been discussed in the literature, experimental investigation to address possible reasons for the variations in the compaction force was conducted with a compaction mechanism. A clearer understanding of the physical compaction process can lead to controllable process parameters for consistent ply compaction, such that the final parts quality can be enhanced. Even though this dissertation investigates the thin thermoset fiber placement process, the proposed approach could be universally applicable to other composite-fabrication processes.
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