Adhesives. Determination of tensile lap-shear strength of rigid-to-rigid bonded assemblies

Unidirectional carbon fiber-reinforced epoxy (UCFRE) is suffering from weak transverse mechanical properties and through-thickness properties. The effect of different amount (0.1, 0.3 and 0.5 phr which is proportional to 0.09, 0.27 and 0.46 wt%, respectively) of multiwall carbon nanotube (MWCNT), on transverse tensile properties, flexural strength, fracture toughness in transverse and longitudinal fiber directions, interlaminar shear strength and lap shear strength of UCFRE has been investigated. Dicyandiamide was used as a thermal curing agent of epoxy resin. MWCNT was dispersed in the epoxy resin by ultrasonic instrument and their dispersion state was investigated by scanning electron microscopy (SEM). The curing behavior of epoxy resin and its nanocomposites was assessed by differential scanning calorimetry. Results show that transverse tensile strength, modulus and strain-at-break were increased by 28.5%, 25% and 14%, respectively by adding 0.1 phr of MWCNT. Longitudinal flexural properties of UCFRE was not changed by adding different amount of MWCNT. Although longitudinal flexural strength was increased by 5% by adding 0.1 phr of MWCNT. Fracture toughness in transverse and longitudinal fiber directions was increased by 39% and 9%, respectively at 0.3 phr of MWCNT. Results also show that interlaminar shear strength and lap shear strength were increased at 0.3 phr of MWCNT by 8% and 5%, respectively. These increases in mechanical properties were due to the good adhesion of fibers to the matrix, interlocking and toughening action of MWCNT as revealed by SEM.

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Lap shear strength and thermal stability of diglycidyl ether of bisphenol a/epoxy novolac adhesives with nanoreinforcing fillers

Journal of Applied Polymer Science ◽

10.1002/app.40017 ◽

2013 ◽

Vol 131 (6) ◽

pp. n/a-n/a ◽

Cited By ~ 19

Author(s):

Mohammad Mansourian-Tabaei ◽

Seyed Hassan Jafari ◽

Hossein Ali Khonakdar

Keyword(s):

Thermal Stability ◽

Shear Strength ◽

Bisphenol A ◽

Diglycidyl Ether ◽

Lap Shear Strength ◽

Lap Shear ◽

Thermal Stability Of

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Bond Strength between Glass Fiber Fabrics and Low Water-to-Binder Ratio Mortar: Experimental Characterization

Advances in Civil Engineering ◽

10.1155/2018/8197039 ◽

2018 ◽

Vol 2018 ◽

pp. 1-10

Author(s):

Daniel Bohling ◽

Andrzej Cwirzen ◽

Karin Habermehl-Cwirzen

Keyword(s):

Mechanical Properties ◽

Shear Strength ◽

Bond Strength ◽

Glass Fiber ◽

Penetration Depth ◽

Pullout Strength ◽

Lap Shear Strength ◽

Lap Shear ◽

Binder Ratio ◽

Water To Binder Ratio

Full utilization of mechanical properties of glass fiber fabric-reinforced cement composites is very limited due to a low bond strength between fibers and the binder matrix. An experimental setup was developed and evaluated to correlate the mortar penetration depth with several key parameters. The studied parameters included fresh mortar properties, compressive and flexural strengths of mortar, the fabric/mortar bond strength, fabric pullout strength, and a single-lap shear strength. Results showed that an average penetration of mortar did not exceed 100 µm even at a higher water-to-binder ratio. The maximum particle size of the used fillers should be below an average spacing of single glass fibers, which in this case was less than 20 µm to avoid the sieving effect, preventing effective penetration. The pullout strength was strongly affected by the penetration depth, while the single-lap shear strength was also additionally affected by the mechanical properties of the mortar.

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