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An improved compression molding technology for continuous fiber reinforced composite laminate. Part 1: AS-4/LaRC-TPI 1500 (HFG) Prepreg systemPoor processability of fiber reinforced high performance polyimide thermoplastic resin composites is a well recognized issue which, in many cases, prohibits the fabrication of composite parts with satisfactorily consolidated quality. Without modifying the resin matrix chemistry, improved compression modeling procedures were proposed and investigated with the AS-4/LaRC-TPI 1500 High Flow Grade (HFG) prepreg system. Composite panels with excellent C-scans can be consistently molded by this method under 700 F and a consolidation pressure as low as 100 psi. A mechanism for the consolidation of the composite under this improved molding technique is discussed. This mechanism reveals that a certain degree of matrix shear and tow filament slippage and nesting between plies occur during consolidation, which leads to a reduction of the consolidating pressure necessary to offset the otherwise intimate inter fiber-fiber contact and consequently achieves a better consolidation quality. Outstanding short beam shear strength and flexural strength were obtained from the molded panels. A prolonged consolidation step under low pressure, i.e., 100 psi at 700 F for 75 minutes, was found to significantly enhance the composite mechanical properties.
Document ID
19910018015
Document Type
Contractor Report (CR)
Authors
Hou, Tan-Hung (Lockheed Engineering and Sciences Co. Hampton, VA, United States)
Kidder, Paul W. (Lockheed Engineering and Sciences Co. Hampton, VA, United States)
Reddy, Rakasi M. (Lockheed Engineering and Sciences Co. Hampton, VA, United States)
Date Acquired
September 6, 2013
Publication Date
May 1, 1991
Subject Category
NONMETALLIC MATERIALS
Report/Patent Number
NASA-CR-187572
NAS 1.26:187572
Funding Number(s)
CONTRACT_GRANT: NAS1-19000
CONTRACT_GRANT: NAG1-569
PROJECT: RTOP 510-02-11
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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