Mode I interlaminar crack length prediction by the resistance signal of the integrated MWCNT sensor in WGF/epoxy composites during DCB test

The interlaminar peformance of composites palys an important role in the damage process of fiber reinforced composites. In-situ monitoring by an embedded sensor could avoid the sudden failure. This paper investigates the in-situ monitoring of mode I interlaminar crack propagationg behavior in woven glass fiber reinforced epoxy (WGF/epoxy) composite laminates. The resistance signal of multi-walled carbon nanotube (MWCNT) located in the mid-thickness of WGF/epoxy during the double cantilever beam (DCB) test is recorded. Relationship between the relative resistance and the interlaminar crack length is theoretically built and experimentally verified. Results show that the mode I crack propagating length can be successfully predicted by the relative resistance. A linear relationship between the interlaminar crack propagating length and the total relative resistance is found by the experimental and theoretical results.