Evaluation of interfacial strength in CF/epoxies using FEM and in-situ experiments

Journal
Composites Part A: Applied Science and Manufacturing  
Volume
37
Issue
12
Start Page
2248
End Page
2256
Citation
Composites Part A: Applied Science and Manufacturing 37 (12): 2248-2256 (2006-12-01)
Publisher DOI
10.1016/j.compositesa.2005.12.021
Scopus ID
2-s2.0-33750971132
Publisher
Elsevier
A combined experimental and numerical study has been carried out in order to study the mechanism of initial failure in transversely loaded CF/epoxy composites. Two composites with a high and a low temperature-curing matrix were investigated. Three point bending experiments on macroscopic composite specimen with special laminate lay-ups were carried out in a scanning electron microscope (SEM). The in-situ experiments allow observing the onset of microscopic composite failure under transverse loading and measurement of the macroscopic applied load at onset of failure. The experimental results show that interfacial failure was the dominating failure mechanism for both materials. For the same carbon fiber with the same treatment the interfacial failure was adhesive (weak interface) or cohesive (strong interface), depending on the matrix system. The interfacial stresses at initiation of failure were determined successfully by a non-linear micro/macro FE-analysis and compared with experimental results obtained from micro composite test. The results show that the interfacial normal strength (INS) governs failure under transverse loads.
Subjects
B. Fibre/matrix bond
B. Interface/interphase
B. Transverse cracking
C. Finite element analysis (FEA)
In-situ testing
DDC Class
600: Technik
More Funding Information
This work was supported in the frame of the collaborative program of the German Research Foundation (DFG) and the Japan Society for the Promotion of Science (JSPS).