Utilization of nanoindentation to examine bond line integrity in adhesively bonded composite structures

2016 ◽  
Vol 204 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Denizhan Yavas ◽  
Xu Shang ◽  
Wei Hong ◽  
Ashraf F. Bastawros
2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Sadik Omairey ◽  
Nithin Jayasree ◽  
Mihalis Kazilas

AbstractThe increasing use of fibre reinforced polymer composite materials in a wide range of applications increases the use of similar and dissimilar joints. Traditional joining methods such as welding, mechanical fastening and riveting are challenging in composites due to their material properties, heterogeneous nature, and layup configuration. Adhesive bonding allows flexibility in materials selection and offers improved production efficiency from product design and manufacture to final assembly, enabling cost reduction. However, the performance of adhesively bonded composite structures cannot be fully verified by inspection and testing due to the unforeseen nature of defects and manufacturing uncertainties presented in this joining method. These uncertainties can manifest as kissing bonds, porosity and voids in the adhesive. As a result, the use of adhesively bonded joints is often constrained by conservative certification requirements, limiting the potential of composite materials in weight reduction, cost-saving, and performance. There is a need to identify these uncertainties and understand their effect when designing these adhesively bonded joints. This article aims to report and categorise these uncertainties, offering the reader a reliable and inclusive source to conduct further research, such as the development of probabilistic reliability-based design optimisation, sensitivity analysis, defect detection methods and process development.


Author(s):  
Roohollah Sarfaraz ◽  
Luis P. Canal ◽  
Georgios Violakis ◽  
John Botsis ◽  
Véronique Michaud ◽  
...  

2017 ◽  
Vol 17 (5) ◽  
pp. 1166-1177 ◽  
Author(s):  
Till Augustin ◽  
Julian Karsten ◽  
Bodo Fiedler

The study deals with an online monitoring approach for adhesively bonded composite joints. A modification of epoxy-based adhesive films with carbon nanotubes allows for electrical resistance measurements through the bonding via inkjet-printed silver conductive circuits on the composites structure. Impact damages are introduced into adhesively bonded glass fiber–reinforced polymer specimens. In-plane and through-thickness electrical resistance measurements show the possibility of accurate damage detection and damage localization of the introduced damages in one or two dimensions, depending on the conductive path designs. The measured electrical resistance changes are compared with results from ultrasonic inspections and light microscopy observations. Furthermore, a linear correlation of electrical resistance and bond line thickness was found. The results demonstrate the applicability of the presented method in a structural health monitoring system.


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