Estimating self-healing capability of carbon fiber/epoxy composites using ultrasonic guided wave

Abstract

In this work, two types of self-healing composite laminates with embedded 6 and 12 wt% microcapsules respectively, were prepared. The guided waves were activated and captured using piezoelectric transducer in a pitch-catch approach. Mode I interlaminar fracture tests were conducted using double cantilever beam specimens, and the effects of concentration of microcapsules on the interlaminar properties of specimens were investigated. The interlaminar fracture surfaces of self-healing specimens were observed to support the analysis of mechanical tests and guided wave detecting results. The results show that the self-healing efficiency of specimens with high-concentration microcapsules is less than that of specimens with low-concentration microcapsules. Meanwhile, low-concentration microcapsules reduce the interlaminar properties of specimens. Two guided-wave parameters, namely signals peak value and waveform similarity, were set and correlated with the self-healing capability of specimens. When the specimens were damaged, the peak value of response signals decreases, and the waveform difference between the response signal and reference signal becomes larger. When the specimens were healed, the peak value of response signals rises, and the waveform difference between them becomes smaller.

Keywords

• Composite laminates
• Microcapsules
• Self-healing
• Interlaminar properties
• Ultrasonic guided wave