Paper number 234


C. Ageorges, K. Friedrich, J. Karger-Kocsis

Institut für Verbundwerkstoffe
Erwin Schrödinger Str., Ge. 58.
D-67663 Kaiserslautern, Germany

Summary The single fibre Broutman test was selected for investigating the fibre/matrix interface debonding behaviour when subjected to a transverse tensile stress. PAN-based carbon fibres having different surface finishes and glass fibres were embedded in epoxy and/or polyester resins and tested. During testing, damage was detected using visual observation and Acoustic Emission (AE) monitoring. AE failure mechanism separation was based on parameters from the time-amplitude domain (event width and amplitude) and on Fast Fourier Transform (FFT) frequency spectra. Stresses in the specimens were evaluated using a two dimensional Finite Element Model (FEM). Two failure mechanisms appeared to be in competition in the Broutman test: (a) fibre compressive fragmentation, characteristic of the shear properties of the interface, and (b) fibre/matrix interface debonding under transverse tensile stresses, characteristic of the transverse properties of the interface. Thermal residual stresses were investigated and a FEM simulation showed that they encouraged fibre compressive fragmentation.
Keywords Broutman test, fibre/matrix interface, transverse debonding, compressive fragmentation, acoustic emission.

Theme : Interface and Interphase ; Mechanical Properties

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