Mode I Fatigue Fracture and Damage Sensing of Bonded CFRP Joints Using CNT Networks in Adhesive Layer

Abstract

This paper studies the Mode I fatigue fracture and damage sensing of bonded carbon fiber reinforced polymer (CFRP) composite joints with carbon nanotube (CNT)-based polymer adhesive layer. Mode I fatigue tests were conducted on double cantilever beam (DCB) bonded joint specimens. The responses in the electrical resistance of the bonded joint specimens were measured during the tests. The effective crack length estimated from the specimen compliance was introduced to describe the fatigue damage development, and an analytical model based on the electrical conduction mechanism of CNT-based polymers was used to predict the electrical resistance change of the bonded joint specimens during fatigue loading. A comparison of the predicted results with the experimental data showed that the analytical model captures the electrical resistance behavior.