Ultrasonic guided waves for health monitoring of high-pressure composite tanks

Nondestructive Testing of Polymers and Polymer–Matrix Composites

“…Further enhancements of acoustic amplitudes are achieved among others by focusing with lenses (260), using multiple element arrays (261) or with transducers attached to a steel cavity in conjunction with time reversal mirroring (262). ACUS is widely used today for material characterization (245,263), defect detection (264)(265)(266), and process and health monitoring (255,267,268).…”

“…ACUS and LUT, both, are useful for Lamb wave applications for plates (270), rods (271), and tubes (267,272), or surface (Rayleigh) waves (273). The combination of recording guided ultrasonic waves with numerical backcalculation of wave propagation for detecting indications of defects in PMC pipes also looks promising (274).…”

Ultrasonic Guided Waves for Health Monitoring of High Pressure Composite Tanks

“…More specifically, moduli of viscoelasticity, C,y, have been inferred and the imaginary parts of Cgg or C55, which are Coulomb moduli in planes of symmetry formed by axis 1 (normal to the plate) and 2 or 3 (in-plane), respectively, have been shown to significantly vary with the moisture content [3,4]. Table 1 presents a set of Q, measured in plane P12, at three different states of a 5 mm thick, [0/90](5s carbon-epoxy plate: initial state after the sample is made, humid saturation state after four months spent in an oven at 65°C and with 70% of humidity, and dry state after two months spent in an oven at 65°C with practically no humidity.…”

“…In the same way, ultrasonic measurements have been made on plate specimen submitted to thermal fatigue, and inverse problems have been used for quantifying the effects on the material stiffness [2,3]. For example.…”

“…Air-coupled transducers may provide solutions to these demands, and since they also guarantee very reproducible measurements, they are good candidates for replacing traditional contact transducers coupled with gel. In this paper, some correlations between complex moduli of viscoelasticity and micro-cracking [2,3] or moisture content [4] in Carbon epoxy plates are firstly reminded. Probable changes in Carbon epoxy properties are then used as input data in a wave propagation model based on the Surface impedance matrices method [5], for predicting the behaviour of wave modes guided in a high-pressure composite tank made of a Titanium liner with Carbon fibres wound around it.…”