Investigation of Interlaminar Shear Properties of CFRP Composites at Elevated Temperatures Using the Lempel-Ziv Complexity of Acoustic Emission Signals

Abstract

Three-point bending tests on Short Beam Shear (SBS) specimens are performed to investigate the interlaminar shear properties of plain weave fabric CFRP composites. The tests are performed in a controlled environmental chamber at two different elevated temperatures. The interlaminar shear properties of the specimens remain largely unaffected by the testing temperature. However, the SEM micrographs show different damage progressions between the specimens tested at 100 °C and 120 °C. Fibre ruptures and longer delamination between the plies, as a result of a high temperature, are observed in the specimens tested at 120 °C, which are not observed in the specimens tested at 100 °C. In addition, the acoustic emission activities during the tests are investigated by using piezoelectric sensors. The information-theoretic parameter, the Lempel-Ziv (LZ) complexity, is calculated for the recorded acoustic signals. The LZ Complexities are used for identifying the occurrence of the first delamination failure in the specimens. Additionally, the two features of the acoustic signals, LZ complexity and Weighted Peak Frequency (W.P-Freq), are used for distinguishing the different damage sources in the CFRP specimens. The results are well-supported by the time-frequency analysis of the acoustic signals using a Continuous Wavelet Transform (CWT).

Effect of temperature on flexural and interlaminar shear strength properties of carbon‐epoxy composites: Experiment and modeling

“…All these investigations were made at RT, but it is also important to investigate the effect of temperature on the ILSS of CFRP composites. Barile et al 18 analyzed the performance of CFRP composites at 100 and 120°C using acoustic emission studies to investigate delamination during ILSS tests. In another study, ILSS of pultruded CFRP (thermoplastic) composites were tested at different temperatures as thermoplastics provide better torsional stiffness and resistance to shear deformation 19 .…”

Effects of High Temperatures on the Performance of Carbon Fiber Reinforced Polymer (CFRP) Composite Cables Protected with Fire-Retardant Materials

“…Carbon fiber reinforced polymer (CFRP) cables are lightweight and have high strength, fatigue resistance, corrosion resistance, and high seismic performance [1][2][3][4]. Carbon fiber materials are widely used [5][6][7][8][9][10][11][12] to strengthen buildings and bridges. In bridges with a cable support system, CFRP cables can be substituted for steel cables, thus reducing the weight of the bridges, decreasing the scale of the substructure, and allowing increased bridge span, reducing the overall bridge cost and the technical challenges of construction [13,14].…”