Characterisation of moisture diffusion and strength degradation in an epoxy-based structural adhesive considering a post-curing process

Han, Xiao; Yong, Jin; Zhang, Wei; Hou, Wenbin; Yu, Ye

doi:10.1080/01694243.2018.1436876

Cited by 40 publications

(14 citation statements)

References 26 publications

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“…In the second stage, the upper and the lower surfaces of the sandwich panel were printed one time, whereas the high-flexible core was printed separately. Due to the wide range of structural adhesives used in bonding different material, 55 the three printed pieces were bonded together using Araldite structural epoxy 56 with slow curing time (90 min) to endure the distribution of the epoxy over the entire surface of the core piece and to avoid wasting epoxy during the layup process. 57 Three samples of each configuration were made to test them by the standard three-point flexural test.…”

Section: Methodsmentioning

confidence: 99%

Mechanical performance of three-dimensional printed sandwich composite with a high-flexible core

Ahmed

Alnajjar

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part L:

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This paper aims to investigate experimentally and using finite element analysis the performance of using three-dimensional printing technology to produce a composite sandwich panel that is made of the high-flexible core as well as with high stiffness upper and lower surfaces made of a glass fiber reinforced composite filament. There are many advantages of using sandwich structures in many applications, especially the aerospace field, where the high stiffness to strength and the lightweight is the most preferred in such applications. The conventional manufacturing methods that are used to produce sandwich panels are limited to particular core geometry, whereas manufacturing a composite core is not possible by these traditional production methods. So by using additive manufacturing technology, it becomes more applicable to design a combination of different geometries and materials to achieve properties that have never been made before, especially combining flexibility and high energy absorption keeping high strength to failure. A central deflection to a length of 0.26 is observed within the elastic zone, a remarkable ratio in beams that reflects the three-dimensional printed sandwich beams’ capability with a highly flexible core to absorb energy that would open doors for many industrial applications that is attributed to the lowest flexural rigidity (167E-3Pa · m4) of the sandwich by using the TriHex infill pattern. In contrast, the Gyroid infill structure could afford the highest central load (0.264 kN). At the peak load applied on the sandwich beam, a maximum error of 5.4% is estimated by finite element analysis lower than the experimental values.

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Section: Methodsmentioning

confidence: 99%

Mechanical performance of three-dimensional printed sandwich composite with a high-flexible core

Ahmed

Alnajjar

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part L:

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“…Thus, to improve the joint strength, methods that favor adhesion have been studied [7,32,70,[83][84][85], going far beyond surface cleaning. Methods include primer application (to promote chemical adhesion), chemical cleaning, sanding, blasting, peel ply (to increase roughness of composites), atmospheric pressure plasma treatment (APPT), used to increase surface energy [19,71,[86][87][88][89][90][91].…”

Section: Surface Treatment Of Adherendsmentioning

confidence: 99%

“…Therefore, many studies have analyzed the influence of environmental phenomena on adhesive bonded joints [21,22,38,49,98,100]. Among these factors are operating temperature, which can be high or low [52,65,107], humidity and immersion in water [19,47,80,107], saltwater mist or spray [50,108,109], corrosion [51] and UV exposure [20,49]. Moreover, the simultaneous or cyclic combination of these factors can intensify the changes caused in the joints.…”

Section: Environmental Factorsmentioning

confidence: 99%

“…Since the overall performance depends on the response of the individual components of the joint, the reliability of dissimilar joints can be even more critical if the adherend materials have relative differences in their thermal expansion behavior [6]. This fact has motivated studies of environmental degradation and fatigue life of the adhesive and adherend materials [18][19][20][21][22][23][24]. The lifetime of the final product, the adhesive bonded joint, is affected not only on the individual behavior of its components, but also the behavior of the entire exposed joint, resulting from the manufacturing process and posterior degradation in service life [2,6].…”

Section: Introductionmentioning

confidence: 99%

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A review of the relationship between design factors and environmental agents regarding adhesive bonded joints

Gualberto

Amorim

Costa

2021

J Braz. Soc. Mech. Sci. Eng.

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Fiber-reinforced polymers (FRPs) combine characteristics of polymers and fibers to obtain a material with high mechanical strength and stiffness together with low specific mass and good corrosion resistance. The use of FRPs is growing as an alternative to metals in the automotive, aerospace and civil construction industries. Since adhesive bonded joints are an excellent way of joining materials due to the better load distribution, the use of FRPs for this purpose has been the objective of many studies about durability and structural safety. In service, environmental factors, including temperature, humidity, UV exposure and salt spray, can degrade materials, leading to unexpected failures. Since joints in service are subject to these multiple and uncontrolled adverse conditions, FRP adhesive bonded joint degradation has been studied by experiments that simulate these adverse environmental conditions. The combined analysis of the effect of environmental factors on the joint and the materials of each component allows predicting the system performance. In addition, optimal design parameters, such as the thickness of the adhesive, overlap length, materials and manufacturing processes, may be different according to the target application of the joint. Therefore, the achievement of optimal design parameters depends on the understanding of joint behavior in service. Based on analysis of the contribution of researchers in the specialized literature on adhesive joints and FRPs, this article reviews the main findings on degradation of adhesive joints and their components. Research topics for optimization of adhesive joint systems are also discussed.

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“…The strength degradation of adhesive-bonded joints under hygrothermal conditions has been studied by numerous researchers. Han et al [1] reported on the moisture diffusion process in adhesives under distilled and salt water. They reported that a saltwater environment significantly accelerated water diffusion and hygroscopic swelling in joints, inducing a significant degradation in joint mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Surface Treatment for Improving Durability of Aluminum-Lithium Adhesive-Bonded Joints under Hot-Humid Exposure

Huang

et al. 2019

Coatings

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The performance of adhesive-bonded joints, which are being increasingly used in the aerospace and automotive industries, under hot-humid conditions remains largely unknown. The effect of surface treatments on the strength durability of aluminum-lithium (Al-Li) alloy adhesive-bonded joints under hot-humid exposure was investigated. Varied surface characteristics were achieved by different mechanical and chemical treatments; combined mechanical and phosphoric acid anodization (PAA) treatments were also used. The adhesive-bonded joints were then exposed to a hot-humid environment. The surface morphology, strength degradation, failure modes, and corrosion resistance of the substrates were analyzed. The results indicated that the combined PAA/mechanical method improved the joint durability under hot-humid exposure. The treated surface, with a roughness of 2.85 μm, exhibited the best durability, losing only 6% of strength after exposure; the failure mode remained cohesive-failure dominant. The durability enhancement was attributed to the porous and moderate rough surface characteristics, which protected the substrate from corrosion and decreased the rate of moisture diffusion from the bonding interface, thereby reducing the degradation of the bonding interface and improving the durability of the joint.

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Characterisation of moisture diffusion and strength degradation in an epoxy-based structural adhesive considering a post-curing process

Cited by 40 publications

References 26 publications

Mechanical performance of three-dimensional printed sandwich composite with a high-flexible core

Mechanical performance of three-dimensional printed sandwich composite with a high-flexible core

A review of the relationship between design factors and environmental agents regarding adhesive bonded joints

Surface Treatment for Improving Durability of Aluminum-Lithium Adhesive-Bonded Joints under Hot-Humid Exposure

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