Experimental analysis of matrix cracking in glass fiber reinforced composite off-axis plies under static and fatigue loading

Research output: Contribution to journalResearch articleContributedpeer-review

Abstract

The inter-fiber failure of glass fiber-reinforced epoxy specimens with four different fiber angles was analyzed. Flat specimens were subjected to static and fatigue loading considering different load levels and load ratios. Damage investigation in terms of crack density measurement was performed by transmitted white light imaging using a digital camera and LED illumination from the back of the specimen on a servo-hydraulic testing machine. Static and fatigue results were examined with respect to crack initiation and crack growth, considering the special case of bonding yarns parallel to the fiber directions. The bonding yarns act as stress concentrations, influencing the early cracking behavior, and complicate the detectability of cracks growing underneath or next to the bonding yarns. In cyclic loading, the influence of load level, load ratio, mean stress, fiber orientation, and ply thickness was the focus of the experimental campaign. Cyclic cracking behavior in terms of initiation and growth was analyzed based on the applied loading conditions and laminate configurations. It was found that halving the ply thickness nearly doubled the amount of microcracks in case of high loads. For low loads, no such effect was observed up to 5×105 loading cycles. Experimental findings on individual crack growth confirmed that crack interaction started for crack spacings less than four times the ply thickness and that subsequent crack growth shifted into regions of larger local crack spacing.

Details

Original languageEnglish
Article number2160
Number of pages22
JournalPolymers
Volume14
Issue number11
Publication statusPublished - 1 Jun 2022
Peer-reviewedYes

External IDs

WOS 000809104800001
Mendeley d8574f81-5741-3323-b500-29eb0352e2bd
Scopus 85131362409
ORCID /0000-0003-1370-064X/work/142243741

Keywords

DFG Classification of Subject Areas according to Review Boards

Keywords

  • fatigue, glass fiber, matrix cracking, polymer-matrix composites, transverse cracking