Residual stress reduction during composite manufacturing through cure modification: In situ analysis. (March 2022)

• Record Type: Journal Article
• Authors: Chava, Sandeep; Namilae, Sirish; Al-Haik, Marwan
• Is Part Of: Journal of composite materials. Volume 56:Number 6(2022)
• Page Start: 975
• Page End: 988
• Publication Date: 2022-03
• Subjects: Autoclave processing -- digital image correlation -- residual stresses -- modified cure cycle -- thermal image analysis; Composite materials -- Periodicals; Composites -- Périodiques; 620.118
• DOI: 10.1177/00219983211066545
• Languages: English
• ISSNs: 0021-9983

Abstract

Residual stresses are detrimental to composite structures as they induce processing defects like debonding, delamination, and matrix cracking which significantly decrease their load-bearing capability. In this research, a new in-situ approach using digital image correlation is utilized to analyze the effect of the cure cycle modification on residual stress evolution during processing. It was found that the modified cure cycle comprising abrupt cooling after gelation reduces the residual stresses. Five different layup configurations are investigated to examine the effect of fiber direction. A maximum average residual stress reduction of 31.8% is observed for the balanced unsymmetric [30/-30/60/-60] laminate. The residual stress reduction results in an increase in failure strength between 4 and 12% in the different layups and can lead up to a 22% increase in first-ply failure strength.