Delamination Induced by Low-Velocity Impact and Influence of Water Absorption on Delamination and CAI of FRPs

• Published in: Transactions of the Japan Society of Mechanical Engineers Series A Vol. 63; no. 610; pp. 1198 - 1204
• Main Authors: KOMAI, Kenjiro, MINOSHIMA, Kohji, TANAKA, Kazuto
• Format: Journal Article
• Language: English; Japanese
• Published: The Japan Society of Mechanical Engineers 1997
• Subjects: Aramid Fiber Reinforced Epoxy Matrix Composite; CF/PEEK Composite; Composite Material; Compression After Impact; Delamination; Impact Loading; Nondestructive Inspection; Scanning Acoustic Microscope; Water Absorption
• ISSN: 0387-5008; 1884-8338
• DOI: 10.1299/kikaia.63.1198

An investigation of water absorption effects on the impact fracture mechanism and compression after impact (CAI) behavior was conducted using carbon fiber reinforced thermoplastic matrix composite (AS-4/PEEK) and aramid fiber reinforced epoxy matrix composite (K-49/828), which have a quasi-isotropic stacking sequence of [0°/±45°/90°]2s. The impact tests were carried out using a falling weight tester. Impact-induced internal damage was observed with a scanning acoustic microecope (SAM). The delamination area was evaluated by the subtraction method. The delamination area of AS-4/PEEK was much smaller than that of a CF/epoxy composite (MM-1/982X), and no influence of water absorption was observed. In contrast, that of K-49/828 was the largest, and the impact-load-induced delamination area was increased by water absorption. In the case of AS-4/PEEK the compressive strength of the impacted specimen at 3 J was the same as that of a virgin specimen, and no influence of water absorption was observed. Impact energy affected the CAI strength of K-49/828 as much as that of MM-1/982 X. The fracture surface was closely examined using a scanning electron microscope, and the fracture mechanisms were discussed.