Mixed-mode fracture analysis of composite bonded joints considering adhesives of different ductility

Santos, Miguel Augusto; Campilho, R.D.S.G.

doi:10.1007/s10704-017-0219-x

Cited by 26 publications

(49 citation statements)

References 54 publications

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“…The pre-preg was supplied in roll form, with a thickness of 0.15 mm. To obtain the adherends thickness of 3 mm, defined during the adhesively-bonded joint design, 20 layers of carbon-epoxy pre-preg were cut with the adherends dimensions, hand-lay-up and cured in a hot-plates press for 1 hour at 130 °C and pressure of 2 bar [63]. The elastic-orthotropic properties of a unidirectional lamina for similar curing conditions are shown in Table 1.…”

Section: Adherendsmentioning

confidence: 99%

“…[64][65][66] and Faneco et al [67]. Overall, all the structural adhesives were two-part adhesives, which combined the resin with a hardener, and featured low viscosity to ensure an easier application on the adherends [63].…”

Section: Adherendsmentioning

confidence: 99%

“…The SLB specimen geometry was established based on two requirements. The first was the compliance of the 70/100 ratio between a0 and L. This criterion is considered as an experimental rule for good practices, which was already tested and validated by several researchers [63]. The second requirement was the acknowledge of the limitations related with the manufacturing process, mainly due to the moulds' availability, restricting the specimens' final dimensions.…”

Section: Slb Geometrymentioning

confidence: 99%

“…The overall thickness of the adhesively-bonded joint specimen can be defined as ht and it had a value of 7 mm. Due to the SLB geometry, the upper adherend was manufactured with 280 mm length, whereas the lower adherend was cut to 200 mm [63].…”

Section: Slb Geometrymentioning

confidence: 99%

“…The experimental tests were performed on seven specimens for each kind of adhesive, considering the same experimental conditions. The experimental results were obtained by Santos and Campilho [63] and were then analyzed in the scope of this thesis.…”

Section: Specimens' Testingmentioning

confidence: 99%

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J-integral analysis of the mixed-mode fracture behaviour of composite bonded joints

Loureiro

Campilho

Rocha

2019

The Journal of Adhesion

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The adhesive technology has been constantly growing and expanding into industrial environments, not only for traditional applications but also for high-end applications, where it has been competing fairly with the conventional connection technologies, such as welding, brazing, bolting and riveting. Its unique key features allow it to raise the type of technology to unreachable levels, for certain applications, by its competitors. Some of the advantages are the lightness of the adhesively-bonded joints, good behaviour under cycling and fatigue loading conditions, flexibility in bonding several types of materials and low stress concentrations. However, in order to design and develop efficient adhesively-bonded joints, the strength prediction must be accurate for the assessment of the fracture properties, mainly the critical energy release rate for tensile (JIC) and shear (JIIC), associated to the mode I and II, respectively. For most of the adhesively-bonded joints applications, the loading conditions under operational service feature a combination of different stresses, for instance tensile and shear stresses, from which the concept of mixed-mode came to exist. For this reason, the assessment of fracture properties under those conditions is essential, especially the energy release rates related to different mode-mixities. The fracture properties are related to Fracture Mechanics and are obtained through energetic analyses, from which three methods are often used: models based on the measurement of the crack length during the damage propagation, models based on an equivalent crack length and methods based on the Jintegral formulation. In the specific case of the J-integral it is furthermore possible to obtain the cohesive laws of the adhesive, which can be later used in the design of adhesively-bonded joints. This current work presents an experimental and numerical analysis of a Single-Leg Bending (SLB) adhesively-bonded joint where the specimens were bonded with three distinct adhesives, in order to assess and compare their behaviour under mixed-mode load conditions, fracture properties and cohesive laws. For that purpose, the J-integral formulation of Ji et al. [1] was considered to obtain the energy release rate for mode I and II, tensile (JI) and shear (JII), respectively, whereas the cohesive laws are attained through direct differential operation of the JI-w0 and JII-δ0 curves, where w0 and δ0 are the local normal separation and local tangential slip between the two adherends at the

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Section: Adherendsmentioning

confidence: 99%