Failure investigation of top-hat composite stiffened panels

Abstract

This paper presents a study on failure investigation of top-hat composite stiffened panels using a combination of techniques. Acoustic emission technique is used to discriminate between the various failure modes using piezoelectric sensors. In addition, an attempt is made to investigate the possibility of using a state of the art surfaced bonded fibre-optic sensor as an acoustic sensor. A strain insensitive fibre Bragg grating (FBG) sensor is used to compare the performance of piezoelectric sensors for composite structures. On the other hand, fibre-optic sensors have some beneficial properties such as low specific weight, small size and good compatibility with polymeric composites compared to traditional sensing mechanisms. FBG sensors are expected to provide a replacement for traditional electric sensors as FBGs are not susceptible to electromagnetic signature, have multi-functionality and enable multiplexing. Fibre-optic sensors are embedded in the composite specimen to measure the non-linear strain at the bend and to analyse the progressive failure with strain anomalies.

Experimental and numerical analyses of stiffened composite panels with delamination under a compressive load

“…Prusty et al. 13 investigated top-hat composite stiffened panels using acoustic emission to discriminate between the various failure modes.…”

“…The test results revealed that minor imperfections due to manufacturing and residual thermal strains can result in large differences in the postbuckling response. Prusty et al 13 investigated top-hat composite stiffened panels using acoustic emission to discriminate between the various failure modes.…”

A monitoring technique for disbond area in carbon fiber–reinforced polymer bonded joints using embedded fiber Bragg grating sensors: Development and experimental validation

“…Bondlines in the composite structural components have also been assessed using FBG sensors. 26–33 Kamath et al 26 used embedded and/or attached FBGs to monitor strains of composite box structures and detected abnormal strain responses near artificially introduced disbonds. Takeda et al 27,28 detected nonlinear strain due to buckling by FBG sensors embedded at the skin–flange interface.…”

“…They also concluded that a full-spectrum measurement (not just at the center wavelength) effectively monitored damage because the reflection spectrum was broadened by the damage. Prusty and Raju 29 specified the failure mode by acoustic emission measured by attached FBG sensors. They also measured damage-induced strain change using embedded FBG sensors.…”