Hygrothermal Properties of Highly Toughened Epoxy Adhesives

Ameli, Amir; Datla, Naresh V.; Papini, M.; Spelt, J.K.

doi:10.1080/00218464.2010.482405

Cited by 64 publications

(30 citation statements)

References 25 publications

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“…These values are in accordance with literature, which predicts an increase in plasticization [34]. The GIC, in dry conditions, increased from 1.5 N/mm to approximately 3.9 N/mm.…”

Section: Fracture Envelope Analysis For Wet and Dry Conditionssupporting

confidence: 92%

Determination of the fracture envelope of an adhesive joint as a function of moisture

Rodrigues¹,

Chaves

Silva³

et al. 2017

Materialwissenschaft Werkst

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Adhesively joints are increasingly being used in aerospace, automotive and maritime industries.The use of this type of joining provides some advantages such as reduction in weight and cost.However, adhesive joints in transportation industry may be exposed to aggressive environments such as high humidity during their service life. A particular issue with the reliability of adhesive joints is the presence of cracks and flaws. Fracture mechanics tests for adhesive joints provide relevant mechanical properties to determine the adhesive toughness and play an important role in design process.This research aims to determine the fracture toughness of aluminum/adhesive/aluminum joints under pure mode I, pure mode II and mixed mode loadings. The fracture characterization of adhesively joints was performed when these specimens were submitted to mixed mode loadings and pure modes (shear and opening). The experimental tests Double Cantilever Beam (DCB) and End-Notched Flexure (ENF) were also done in order to assess the fracture toughness in pure modes I and II, respectively. A mixed mode apparatus was used to perform the mixed mode tests from pure mode I to near mode II. Test for dry and wet condition were performed with the main purpose to predict the influence of humidity in the toughness properties. The adhesive characterized was a ductile epoxy adhesive, Nagase Chemtex ® XNR 6852E-2.The diffusion coefficient was measured and the water uptake behavior was studied for a temperature of 50 ºC. Finite element analysis (FEA) was carried out to predict the moisture content in the adhesive layer, using ABAQUS ® .The influence of water in the behavior of the adhesive joint (DCB) was verified by changes in the values of the fracture mechanics properties. The load necessary to initiate a crack propagation is lower for aged adhesive joints when compared with dry adhesive joints for pure modes and different mixed mode ratios. vi vii ResumoAs ligações adesivas são cada vez mais utilizadas na indústria aeroespacial, automóvel e naval.A utilização deste tipo de ligação fornece algumas vantagens, tais como redução do peso e do custo. Contudo, na indústria dos transportes, estas ligações podem ser expostas a ambientes agressivos, tais como ambientes com elevada humidade durante a sua vida útil. Uma questão particular é a fiabilidade das juntas adesivas na presença de fendas e falhas. Os ensaios de mecânica da fratura para juntas adesivas proporcionam propriedades mecânicas relevantes, de forma a determinar a resistência adesiva e desempenham um papel importante no processo de design de juntas.Esta pesquisa tem como objetivo determinar a tenacidade à fratura de juntas de alumínio / adesivo / alumínio em modo puro I, II e modo misto. A caracterização à fratura de juntas adesivas foi realizada quando estas estavam submetidas a cargas de modo misto e modos puros (corte e abertura). Os ensaios Double Cantilever Beam (DCB) e End-Notched Flexure (ENF)foram realizados para avaliar a resistência à fratura em modos puros I e II, respetiv...

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“…These values are in accordance with literature, which predicts an increase in plasticization [34]. The GIC, in dry conditions, increased from 1.5 N/mm to approximately 3.9 N/mm.…”

Section: Fracture Envelope Analysis For Wet and Dry Conditionssupporting

confidence: 92%

Determination of the fracture envelope of an adhesive joint as a function of moisture

Rodrigues¹,

Chaves

Silva³

et al. 2017

Materialwissenschaft Werkst

View full text Add to dashboard Cite

show abstract

“…The containers should be large enough to accommodate several specimens so that they can be exposed to an identical environment at the same time. Saturated salt solutions can be used to achieve different RH levels and corresponding ambient water concentrations at different temperatures, as shown in Table 5.2 [24]. To achieve 100% RH, deionized water should be used instead of salt solution.…”

Section: Agingmentioning

confidence: 99%

Durability

Giannis¹,

Davies

Ameli

et al. 2012

Testing Adhesive Joints

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“…Other models have been developed, such as the dual fickian diffusion (Loh et al 2005), delayed dual fickian (Mubashar et al 2009) and the Langmuir model (Ameli et al 2010). In many cases the water uptake may be fickian under certain environmental situations and nonfickian under others.…”

Section: Introductionmentioning

confidence: 99%

“…In many cases the water uptake may be fickian under certain environmental situations and nonfickian under others. Generally non fickian behaviour is more prone to happen at higher temperatures (Zhou and Lucas 1995), higher relative humidity (Ameli et al 2010, Loh et al 2005) and smaller thicknesses of the bulk adhesive specimen (Loh et al 2005). There is also evidence that while a bulk adhesive may have a fickian diffusion behaviour, the same adhesive in a joint may have a case II diffusion behaviour (Liljedahl et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Water Diffusion in Double Cantilever Beam Adhesive Joints

Viana

Costa

Silva

2017

Lat. Am. j. solids struct.

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Structural adhesives are increasingly being used in the aerospace and automotive industries. They allow for light weight vehicles, fuel savings and reduced emissions. However, the environmental degradation of adhesive joints is a major setback in its wide implementation. Moisture degradation of adhesive joints includes plasticization, attacking of the interface, swelling of the adhesive and consequent creation of residual stresses. This may lead to reversible and irreversible damage. In this work double cantilever beam (DCB) specimens using two different adhesives for the automotive industry were subjected to two different ageing environments. They were tested periodically until the toughness of the adhesives stabilized, which means that they were fully degraded. An association was made between the toughness of the adhesive and the amount of water that it had absorbed. This way it was possible to indirectly measure the water uptake in an adhesive joint taking into account the water uptake properties of the adhesives studied, which had been determined in another study. It was found that diffusion of water into the studied adhesive joints was faster than diffusion through the bulk adhesive alone. A model that takes into account diffusion through the interface between the adhesive and the adherends was proposed.

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Hygrothermal Properties of Highly Toughened Epoxy Adhesives

Cited by 64 publications

References 25 publications

Determination of the fracture envelope of an adhesive joint as a function of moisture

Determination of the fracture envelope of an adhesive joint as a function of moisture

Durability

Water Diffusion in Double Cantilever Beam Adhesive Joints

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