BOND QUALITY EVALUATION USING ADHESIVE DOPED WITH MAGNETO-ELECTRIC NANOPARTICLES

2021 ◽  
Author(s):  
JULIETTE DUBON ◽  
GONZALO SEISDEDOSMARIANA ONTIVEROS ◽  
MARIANA ONTIVEROS ◽  
BENJAMIN BOESL ◽  
DWAYNE MCDANIEL
Keyword(s):  
Glass Transition ◽  
Composite Structures ◽  
Quality Evaluation ◽  
Adhesive Bonding ◽  
Curing Time ◽  
Bond Quality ◽  
Non Invasive ◽  
Mechanical Fasteners ◽  
Adhesive Quality ◽  
Looper System

Adhesive bonding for composite structures offers multiple advantages over mechanical fasteners. Although the use of adhesive bonding has increased in the aerospace industry, it has still not replaced mechanical fasteners due to it being harder to inspect for damage after being manufactured/assembled, causing unreliability. Therefore, intensive quality control is needed while manufacturing to avoid weak bonds or any type of imperfection at the adhesive-adherend interface. To ensure the reliability of an adhesive bond, this project focuses on the advancement of a non-invasive field tool for adhesive quality evaluation. The tool developed is based on a B-H looper system, which can approximate the quality of an epoxy-based adhesive containing magneto-electric nanoparticles (MENs) by detecting changes in electric fields at the molecular level. Epoxy based adhesive samples containing 5 vol. % of MENs were manufactured and then scanned using the B-H looper system to correlate their magnetic signature as a function of curing time. It was determined that the magnetic signal converged between curing hours 10 and 12, indicating proper curing. Plain adhesive dogbone samples were used to determine the maximum tensile stress of the adhesive as a function of curing time, which also started converging at around the same curing hours until reaching ~41 MPa. Additionally, the evolution of the glass transition temperature of the adhesive was evaluated during the first curing hours. Convergence began at a curing time of 10 hours until reaching ~137 ⁰ C for fully cured samples. B-H looper magnetic signatures, tensile stresses testing, and glass transition temperatures were all correlated indicating a fully cured adhesive sample between 10 and 12 curing hours. These studies demonstrate the capabilities of the B-H looper system as a non-invasive inspection tool for adhesive quality.

scholarly journals Defects and uncertainties of adhesively bonded composite joints

2021 ◽  
Vol 3 (9) ◽  
Author(s):  
Sadik Omairey ◽  
Nithin Jayasree ◽  
Mihalis Kazilas
Keyword(s):  
Composite Materials ◽  
Composite Structures ◽  
Production Efficiency ◽  
Adhesive Bonding ◽  
Detection Methods ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Wide Range ◽  
Bonded Composite

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.

NON-DESTRUCTIVE EVALUATION OF MECHANICAL DAMAGE OF ADHESIVES USING MAGNETO-ELECTRIC NANOPARTICLES

2021 ◽  
Author(s):  
GONZALO SEISDEDOS ◽  
BRIAN HERNANDEZ ◽  
JULIETTE DUBON ◽  
MARIANA ONTIVEROS ◽  
BENJAMIN BOESL ◽  
...  
Keyword(s):  
Adhesive Joint ◽  
Adhesive Bonding ◽  
Mechanical Damage ◽  
Adhesive Bond ◽  
Tensile Tests ◽  
Adhesive Joints ◽  
Adhesive Bonds ◽  
Magnetic Signatures ◽  
Looper System ◽  
Lock In

Adhesive bonding has been shown to successfully address some of the main problems with traditional fasteners, such as the reduction of the overall weight and a more uniformly distributed stress state. However, due to the unpredictability of failure of adhesive bonds, their use is not widely accepted in the aerospace industry. Unlike traditional fastening methods, it is difficult to inspect the health of an adhesive joint once it has been cured. For adhesive bonding to be widely accepted and implemented, there must be a better understanding of the fracture mechanism of the adhesive joints, as well as a way to monitor the health of the bonds nondestructively. Therefore, in-field structural health monitoring is an important tool to ensure optimal condition of the bond is present during its lifetime. This project focuses on the advancement of a non-invasive field instrument for evaluation of the health of the adhesive joints. The tool developed is based on a B-H looper system where coils are arranged into a noise-cancellation configuration to measure the magnetic susceptibility of the samples with a lock-in amplifier. The B-H looper system can evaluate the state of damage in an adhesive bond by detecting changes in surface charge density at the molecular level of an epoxy-based adhesive doped with magneto-electric nanoparticles (MENs). Epoxy-based adhesive samples were doped with MENs and then scanned using the B-H looper system. To evaluate the health of the adhesive joint, microindentation and tensile tests were performed on MENs-doped adhesive samples to understand the relationship between mechanical damage and magnetic signal. Correlations between magnetic signatures and mechanical damage were minimally observed, thus future studies will focus on refining the procedure and damaging methodology.

A Holistic Approach on Cementing and Bond Quality Evaluation of a Depleted Reservoir Drilled with Highly Inclined Well – A Case Study from Offshore Sabah, Malaysia

2020 ◽  
Author(s):  
Saikat Das ◽  
Chitra Charan Suri ◽  
Sebastien Kamgang ◽  
Roger Marsh ◽  
Gerard O'Reilly ◽  
...  
Keyword(s):  
Quality Evaluation ◽  
Holistic Approach ◽  
Bond Quality

Investigation of Conductive Adhesive Bonding Using UV Curable Anisotropic Conductive Adhesives at Different Curing Conditions

2005 ◽  
Vol 127 (1) ◽  
pp. 52-58 ◽  
Author(s):  
K. K. Lee ◽  
S. C. Tan ◽  
Y. C. Chan
Keyword(s):  
Shear Test ◽  
Adhesive Bonding ◽  
Uv Light ◽  
Curing Temperature ◽  
Curing Time ◽  
Conductive Adhesives ◽  
Radical Initiation ◽  
Uv Curable ◽  
Curing Conditions ◽  
Adhesive Materials

Generally, adhesive materials can be cured in a short time under high curing temperature. High curing temperature usually leads to an increase in cross-link density and a homologous increase in heat resistance. Nevertheless, curing process under high temperature problems can occur such as the inclination for the adhesive materials to shrinkage, cracks, voids and it would probably lower the dielectric properties. UV curing of anisotropic conductive adhesives (ACAs) offers several advantages over the conventional epoxy resin, including rapid cure, little to no emission of volatile organic compounds and without affecting other components in the assembly [Pataki, W. S., 1997, “Optimization of Free-Radical Initiation Reactions in the Electrical Industry,” Electrical Insulation Conference and Electrical Manufacturing and Coil Winding Conference Proceedings, pp. 745–751]. Based on the aforementioned advantages, it is worth investigating the bonding properties at different curing conditions. In this work, a new type of UV curable ACA for chip-on-flex application is presented. The adhesive bonds of the chip-on-flex application are cured at different cure cycles within a range of UV frequencies. Cure cycles in this work were the different periods of time that were needed to cure the ACAs under different UV light intensities. Fourier transform infrared spectroscopy with attenuated total internal reflection was used to investigate the curing degree of the ACAs at different cure cycles. The result shows that the longer the curing time and the larger the UV intensity, the higher the curing degree can be obtained. Furthermore, the curing time in the UV curable ACA was much shorter than that of the conventional thermal curable ACAs. Shear test was done to find out the shear strength of the bonding. Finally, after shear test, scanning electron microscope was used to investigate the fracture mode of the chip-on-flex application at different curing cycles.

scholarly journals Contribution to mechanical fasteners for composite structures – An automated industrial approach

2020 ◽  
Author(s):  
Oğuzhan Eroğlu ◽  
Hans Julius Langeheinecke ◽  
Norbert Enzinger ◽  
Fabian Fischer
Keyword(s):  
Composite Structures ◽  
Mechanical Fasteners
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