Monitoring of delamination onset and growth during Mode I and Mode II interlaminar fracture tests using guided waves

Dong Wang, Lin Ye, Youhong Tang, Ye Lu

Research output: Contribution to journalArticleResearchpeer-review

22 Citations (Scopus)

Abstract

A delamination monitoring method was proposed to characterize Mode I and Mode II delamination onset in carbon fiber/epoxy (CF/EP) composite laminates through interrogation of guided waves activated and captured using piezoelectric actuators and sensors in a pitch–catch configuration. Mode I and Mode II interlaminar fracture tests were conducted using double cantilever beam (DCB) and end notch flexure (ENF) specimens to evaluate the proposed method. The changes in wave propagation velocity and wave magnitude (or attenuation), and the degree of waveform similarity between excitation and response signals, were calculated as delamination-sensitive wave parameters and plotted versus displacement recorded using a materials testing system. The kink points determined from wave parameter–displacement
curves agreed well with the deviation from linearity (NL), visual observation (VIS) and maximum load (Max) points, which are often used in conventional methods for determining interlaminar fracture toughness. The propagation characteristics of the A0 wave mode in a low frequency range were demonstrated to have high sensitivity to Mode I and in particular Mode II delamination onset in CF/EP composite
laminates. It was concluded that the guided waves propagating in the DCB and ENF specimens were capable of determining Mode I and Mode II interlaminar fracture toughness, complementing current practices based on visual inspection or trivial interrogation using load–displacement curve alone.
Original languageEnglish
Pages (from-to)145 - 151
Number of pages7
JournalComposites Science and Technology
Volume72
Issue number2
DOIs
Publication statusPublished - 2012
Externally publishedYes

Keywords

  • Stress/strain curves
  • Mechanical properties
  • Fracture toughness
  • Delamination
  • Ultrasonics

Cite this