Modelling anomalous moisture uptake, swelling and thermal characteristics of a rubber toughened epoxy adhesive

Loh, W. K.; Crocombe, A.D.; Wahab, Magd Abdel; Ashcroft, Ian

doi:10.1016/j.ijadhadh.2004.02.002

Cited by 216 publications

(129 citation statements)

References 16 publications

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“…/ t M M ∞ . M ∞ was determined using a dual Fickian model [11] for absorption and a Fickian diffusion model for the desorption. During the first absorption cycle, an increase in strain to failure, over unconditioned specimens, was observed for all moisture concentrations.…”

Section: Resultsmentioning

confidence: 99%

“…Tensile testing of bulk adhesive samples, conditioned at different moisture conditions, may be carried out to obtain moisture dependant stress-strain curves. For example, the moisture dependant mechanical properties of a one part rubber toughened epoxy adhesive were determined by Loh et al [11] using bulk samples of 0.4 and 0.8 mm thickness. The specimens were conditioned at 81.2%, 95.8% relative humidity (RH) and in water at 50°C.…”

Section: Introductionmentioning

confidence: 99%

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A Method of Predicting the Stresses in Adhesive Joints after Cyclic Moisture Conditioning

Mubashar

Ashcroft

Critchlow

et al. 2011

The Journal of Adhesion

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The durability of adhesive joints is of special concern in structural applications and moisture has been identified as one of the major factors affecting joint durability. This is especially important in applications where joints are exposed to varying environmental conditions throughout their life. This paper presents a methodology to predict the stresses in adhesive joints under cyclic moisture conditioning. The single lap joints were manufactured from aluminium alloy 2024 T3 and the FM73-BR127 adhesive-primer system. Experimental determination of the mechanical properties of the adhesive was carried out to measure the effect of moisture uptake on the strength of the adhesive. The experimental results revealed that the tensile strength of the adhesive decreased with increasing moisture content. The failure strength of the single lap joints also progressively degraded with time when conditioned at 50°C, immersed in water, however, most of the joint strength recovered after drying the joints. A novel finite element based methodology, which incorporated moisture history effects, was adopted to determine the stresses in the single lap joints after curing, conditioning and tensile testing. A significant amount of thermal residual stress was present in the adhesive layer after curing the joints, however, hygroscopic expansion after the absorption of moisture provided some relief from the curing stresses. The finite element * Corresponding author. Tel: +44 1509 227535; fax: +44 1509 223934 Email address: i.a.ashcroft@lboro.ac.uk (I.A.Ashcroft) 2 model used moisture history dependent mechanical properties to predict the stresses after application of tensile load on the joints. The maximum stresses were observed in the fillet areas in both the conditioned and the dried joints. Study of the stresses revealed that degradation in the strength of the adhesive was the major contributor in the strength loss of the adhesive joints and adhesive strength recovery also resulted in recovered joint strength.The presented methodology is generic in nature and may be used for various joint configurations as well as for other polymers and polymer matrix composites.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Method of Predicting the Stresses in Adhesive Joints after Cyclic Moisture Conditioning

Mubashar

Ashcroft

Critchlow

et al. 2011

The Journal of Adhesion

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show abstract

“…The stiffness and the tensile strength continue to decrease with increasing moisture content reaching a plateau as the moisture saturation level is approached. [9,13] The same is true for the glass transition temperature. [12] However, exposing the adhesive for a long period after saturation, when no further plasticization occurs, the moisture causes permanent deterioration such as dissolution of inorganic filler [12], chain scission and leaching of the backbone of the chain structure [14][15][16] and crazing and cracking [3].…”

Section: Introductionmentioning

confidence: 70%

The static and fatigue responses of aged metal laminate doublers joints under tension loading

Sugiman

Crocombe

2015

Journal of Adhesion Science and Technology

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Experimental studies have been undertaken to investigate the static and fatigue response of metal laminate doublers (MLD) joints under tension loading after ageing in deionised water at a temperature of 50 o C up to 2 years. It was found that absorbed water did not have a significant effect on the static and fatigue degradation of the MLD; however corrosion pits located on the aluminium surfaces caused a reduction in fatigue life.Inevitably the laminate contained butts where co-planar aluminium sheets were joined, and it was found that the position of the butt affected the static response of the MLD but, due to a restricted dataset, it has not been possible to assess the effect under fatigue loading. The backface strain technique in conjunction with video microscopy has been utilised to monitor the damage of the adhesive bondlines, the butts and the aluminium layers and successfully identified both the localised and the global damage in the MLD.Most of fatigue failures initiated at the stringer bondline edge and at the aluminium layers where the butt was located. A careful design should be made to reduce the stress concentration at the stringer edge and to avoid positioning the butts at the upper layer of aluminium close to the stringer edge.

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“…The curvature in bi-material samples is commonly used as a simple measure of residual stress [18][19][20][21], however, the experimentally measured deflection has to be analysed in order to calculate the stresses and strains [22,23]. Yu et al [24] used steel-epoxy adhesive bi-material strip experiments to investigate residual due to shrinkage of the adhesive on curing (curing stresses), differential thermal contraction of adhesive and adherend on cooling from the curing temperature (thermal stresses) and expansion of the adhesive on absorption of atmospheric moisture (hygroscopic stresses).…”

Section: Introductionmentioning

confidence: 99%

Thermal residual stress analysis of epoxy bi-material laminates and bonded joints

Jumbo

Ashcroft

Crocombe

et al. 2010

International Journal of Adhesion and Adhesives

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Modelling anomalous moisture uptake, swelling and thermal characteristics of a rubber toughened epoxy adhesive

Cited by 216 publications

References 16 publications

A Method of Predicting the Stresses in Adhesive Joints after Cyclic Moisture Conditioning

A Method of Predicting the Stresses in Adhesive Joints after Cyclic Moisture Conditioning

The static and fatigue responses of aged metal laminate doublers joints under tension loading

Thermal residual stress analysis of epoxy bi-material laminates and bonded joints

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