The effect of thermal processing on residual strain development in unidirectional graphite fibre reinforced PEEK

Journal Article · Fri Jan 01 04:00:00 EST 1993 · Journal of Composite Materials; (United States)

DOI:https://doi.org/10.1177/002199839302700105· OSTI ID:6468591

Unger, W J; Hansen, J S ^[1]

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1. Toronto Univ., Downsview (Canada)

The effect of annealing on residual strain development in amorphous graphite fiber reinforced PEEK (APC-2) is studied experimentally. A method is presented for embedding strain gauges in a unidirectional laminate at the time of manufacture and then quenching the laminate into the amorphous state. With this method, thermal and crystallization strains are measured directly during quasi-isothermal heating of the laminate. Both longitudinal and transverse lamina strains resulting from contraction during crystallization are measured. Longitudinal cyrstallization strains are found to be negligible due to fiber stiffness. Transverse contraction due to crystallization is large and increases with anneal temperature. A coefficient of crystalline expansion is defined which is analogous to the CTE. This coefficient describes the permanent crystallization strain as a function of anneal temperature and is determined experimentally. 26 refs.

• OSTI ID: 6468591
• Journal Information: Journal of Composite Materials; (United States), Journal Name: Journal of Composite Materials; (United States) Vol. 27:1; ISSN JCOMBI; ISSN 0021-9983
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
CARBON FIBERS
CRYSTALLIZATION
FIBERS
GRAIN ORIENTATION
MATERIALS
MEASURING INSTRUMENTS
MICROSTRUCTURE
ORGANIC COMPOUNDS
ORGANIC POLYMERS
ORIENTATION
PETROCHEMICALS
PETROLEUM PRODUCTS
PHASE TRANSFORMATIONS
PLASTICS
POLYMERS
REINFORCED MATERIALS
REINFORCED PLASTICS
RESIDUAL STRESSES
STRAIN GAGES
STRESS ANALYSIS
STRESSES
SYNTHETIC MATERIALS
THERMAL STRESSES
THERMOPLASTICS