TOWARDS INTEGRATED HEALTH MONITORING OF BIO-BASED COMPOSITE STRUCTURES: INFLUENCE OF ACOUSTIC EMISSION SENSOR EMBEDMENT ON MATERIAL INTEGRITY

Structural Health Monitoring (SHM) and Natural Fibres Composites (NFC) have livedsince early 2000’s important progress due to the needs of reducing material consumption andweight in operating structures while limiting the environmental footprint and increasing thesafety of such structures. Acoustic Emission (AE) is one of the numerous solutions that appearsto be suitable to predict service life and assess damage in composite structures. NFCs have shownpromising properties for structural applications but their complex behaviour and the limitedknowledge on their long-term durability still hinder their full development. In that sense, AEbasedSHM could allow a more important breakthrough of bio-based composites by monitoringdamage evolution and assessing their remaining life in service conditions. The new generationof AE-sensors offers also opportunities of embedment thanks to their smaller size, leading tobetter protection of the sensors and increased sensitivity. We propose in this work to study theeffect of the embedment of millimetric-size dummy sensors in flax/epoxy laminates on themonotonic tensile behaviour and damage kinetic up to failure through AE methods. Resultshighlight a limited effect of the presence of dummy sensors on the mechanical behaviour andproperties. AE results coupled with X-ray tomography pictures however highlight a change inlocation of damages that are more likely to append in the insert vicinity, and in the onset of themost severe damages, which appears at lower global deformation levels