A study on the FRP composite’s matrix damage resistance by means of elastic wave propagation analysis

Abstract

In the study, selected materials used for fiber reinforced polymer (FRP) composites’ matrices were subjected to Compact Tension (CT) test. During the test acoustic emission (AE) parameters were registered which let to introduce AE technique as a valuable and helpful method to monitoring and identifying polymer failures. Gathering of elastic waves propagation data was conducted with AMSY-5 acoustic emission system produced by Vallen Systeme GmbH, in accordance with Vallen’s user manual. Next, the analysis was done using dedicated software based on Fast Fourier Transform (FFT) and Wavelet Transform (WT). Four cured epoxy resins with different chemical composition were chosen to the investigation. Epidian 5 and Epidian 53 epoxy resins were hardened using the two following curing agents: Z1 triethylenetetramine curing agent and PAC polyaminoamide curing agent. The paper was prepared as a continuation of authors’ previously conducted research on evaluating FRP composites’ matrices strength and damage growth resistance, for the same four materials. Obtained AE results were then discussed in comparison to mechanical tests results, such as fracture toughness and stress/strain characteristics. Therefore, some interesting relations were observed between AE frequency and number of hits/counts which were affected by material composition and its fracture toughness. Moreover, microscopic analysis was conducted to present phenomena appeared on fracture surfaces of broken specimens, including microcracks, “crack arrest” as well as so called river patterns.