Browsing by Author "McCarthy, Conor"

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    Carbon nanotube embedded adhesives for real-time monitoring of adhesion failure in high performance adhesively bonded joints
    (Springer Nature, 2020-10-08) Bregar, Tadej; An, Donglan; Gharavian, Somayeh; Burda, Marek; Durazo-Cardenas, Isidro; Thakur, Vijay Kumar; Ayre, David; Słoma, Marcin; Hardiman, Mark; McCarthy, Conor; Nezhad, Hamed Yazdani
    Carbon nanotubes (CNTs) embedded polymers are of increasing interest to scientific and industrial communities for multi-functional applications. 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. 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. The changes in the piezo-resistivity induced by the CNTs have been monitored in situ with respect to loading. A novel interpretation method has been developed for progressive, instantaneous adhesion failure estimation under cyclic tensile stresses from a resistivity baseline. The method indicates that the in-situ resistivity changes and the rate of the changes with strain, i.e. sensitivity, strongly correlate with the adhesion failure progression, irrespective of the CNT dispersion quality. Moreover, the effect of bond thickness on the evolution of piezo-resistivity and adhesion failure have been studied. It was observed that relatively thin adhesive bonds (0.18mm thickness), possessing higher CNT contact points than thick bonds (0.43mm thicknes), provide 100 times higher sensitivity to varying cyclic loads
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    A study of intra-laminar damage in double-lap, multi-bolt, composite joints with variable clearance using continuum damage mechanics
    (Elsevier, 2014-06-10) Zhou, Yinuha; Yazdani Nezhad, Hamed; McCarthy, M. A.; Wan, Xiaopeng; McCarthy, Conor
    A damage modelling approach, based on a continuum damage model (CDM) formulation, is proposed and applied to the problem of double-lap, multi-bolt, fibre-reinforced composite joints with variable clearances, subjected to quasi-static tensile loading. A new method of dealing with fibre failure is included in the CDM model, which is implemented in a commercial implicit finite element analysis code. The model is validated at element and structural levels by comparing with experimental data. It has been found that, for the joints examined in this paper, our formulation is capable of modelling development of damage from bearing failure onset all the way to ultimate catastrophic net-tension failure without numerical problems, which is an advance over previous work. The predictions from the CDM model of net-tension failure modes and ultimate loads are in good agreement with those from the experiments. Furthermore the model is capable of explaining some non-intuitive experimental findings, such as the larger energy absorption obtained in joints with higher clearances.
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    Underpinning Data for Article: Carbon nanotube embedded adhesives for real-time monitoring of adhesion failure in high performance adhesively bonded joints
    (Cranfield University, 2020-09-25 19:16) Yazdani Nezhad, Hamed; Bregar, Tadej; An, Donglan; Gharavian, Somayeh; Burda, Marek; Durazo-Cardenas, Isidro; Kumar, Vijay; Ayre, David; Sloma, Marcin; Hardiman, Mark; McCarthy, Conor
    The underpinning data for Research Article on Carbon nanotube embedded adhesives for real-time monitoring of adhesion failure in high performance adhesively bonded joints