7/27/2023 0 Comments Carbon nanotube crystalviewer![]() ![]() ![]() A research has examined single-lap bonded joints at different CNT fractions (0.5 wt%, 1.0 wt%, and 2.0 wt%) in epoxy adhesive 1 relying upon the CNT’s piezo-resistivity. in cyclic tension loading, has rarely been investigated. On the other hand, repeatability of the performance of the measurement technology, and therefore its reliability, within the elastic regime, rather than damage progression, e.g. Numerous researches have focused on enabling strain sensing in polymers using functional nanomaterials including CNTs 8, 15, 16, 17, 18, 19, 20, 21, 22, 23 however there are a few researches conducted on the use of such technology for measurement of adhesion failure in adhesively bonded joint structures (e.g. Various researches have been conducted for that detection 6, 12, 13, 14 but there is little research done on strain measurement within the elastic regime of adhesive performing in bonded joints prior to irreversible damage occurring either in adhesive bulk or at its interface with an adherend. Therefore, research in structural health monitoring and bond damage detection methods is essential in order to prevent catastrophic failures that may arise due to barely detectable instantaneous adhesive bond failure 5, 8, 11. adhesion failure) is another downside as non-destructive inspection (NDI) methods are currently limited for reliable detection of such failure when zero-thickness bond defects are present 1, 7, 8, 9, 10. ![]() Furthermore, disassembly of bonded joints for periodic inspections of internal damage (e.g. Mechanical performance of adhesives under peeling stresses (in Mode I fracture opening) is also relatively low 7. However, adhesives are sensitive to variations in service and hygrothermal loads, and also surface preparations 2, 3, 4, 5, 6. Moreover, there is an urgent need to a progressive transition to bonded joints for assembly and joining high performance composite parts e.g. adhesive bonding) for lightness, integrity and multifunctionality. This is surging in an era where traditional methods of joining such as bolting or mechanical fasteners are becoming partly replaced by fastener-less technologies (e.g. As such, use of CNTs in polymer adhesives opens door to a wide range of functions adhesives are used for. Their exceptional mechanical and electrical properties, production scalability and ability to introduce various characteristics to everyday materials widen the spectrum of the tasks conventional materials (e.g. It was observed that relatively thin adhesive bonds (0.18 mm thickness), possessing higher CNT contact points than thick bonds (0.43 mm thickness), provide 100 times higher sensitivity to varying cyclic loads.Ĭarbon nanomaterials have been receiving vast interest in multifunctional applications, among which carbon nanotubes (CNTs) are one of the most researched ones. Moreover, the effect of bond thickness on the evolution of piezo-resistivity and adhesion failure have been studied. sensitivity, strongly correlate with the adhesion failure progression, irrespective of the CNT dispersion quality. The method indicates that the in-situ resistivity changes and the rate of the changes with strain, i.e. A novel interpretation method has been developed for progressive, instantaneous adhesion failure estimation under cyclic tensile stresses from a resistivity baseline. The changes in the piezo-resistivity induced by the CNTs have been monitored in situ with respect to loading. The CNT modified adhesive in bonded joints and the CNT modified adhesive alone have been tested under monothonic and cyclic tensile loads up to ultimate failure. In this article, CNTs have been introduced to high-strength epoxy adhesive for enabling in-situ strain sensing in adhesively bonded aluminium-to-aluminium single-lap joints to accurately indicate the onset and propagation of adhesion failure to the evolution of piezo-resistivity in varying mechanical loads. Carbon nanotubes (CNTs) embedded polymers are of increasing interest to scientific and industrial communities for multi-functional applications. ![]()
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