ISSN: 0884-6804
CODEN: JCTRER
Page Count: 5

Determination of Chemical Cure Shrinkage in Composite Laminates
Karalekas, D
Professor and research assistants, The Robert R. McCormick School of Engineering and Applied Science, Northwestern University, IL

Daniel, IM
Professor and research assistants, The Robert R. McCormick School of Engineering and Applied Science, Northwestern University, IL

Gotro, JT
Polymer scientist, IBM Corporation, NY

Wang, T-M
Professor and research assistants, The Robert R. McCormick School of Engineering and Applied Science, Northwestern University, IL

Abstract

Residual stresses in composites (microscopic and macroscopic) result from shrinkage of the matrix during cure. It is usual to distinguish between the chemical and thermal components of shrinkage. The former depends on the polymerization reaction, whereas the latter is caused by the difference between the thermal expansion coefficients of the reinforcement and the matrix. A method was developed for determination of the chemical cure shrinkage. A prepreg layer is applied on an identical layer of the same material that has already been cured and postcured. The assembled laminate is then cured, and the resulting warpage is recorded by means of the shadow moiré method. The resulting warpage, consisting of elliptical equal deflection contours, is related to the chemical shrinkage.

Keywords:
residual stresses, warpage, composite materials, matrix shrinkage, chemical shrinkage, polymerization shrinkage, moiré method

Paper ID: CTR10194J
DOI: 10.1520/CTR10194J
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