Shear bond strengths

In the push out test [93], the fiber is pushed into the matrix rather than being pulled out. The test allows the measurement of two quantities, Fdcb (the force at which debonding occurs) and F/., (the force needed to push the fiber through the matrix sample if it is thin enough). The bond shear strength Tdeb is calculated using the shear lag theory ... 

An early study by Rudkin (1950) showed that substitution of OH groups with acetyl resulted in a significant decrease in bond strength between the wood and a UF resin in lap-joint tests. Vick and Rowell (1990) studied the adhesive bonding of acetylated yellow poplar, with 18 different thermoplastic and thermosetting adhesives. The effectiveness of the adhesives was examined by determination of bond shear strength (and wood failure) of 6 mm thick, bonded wood strips after conditioning at 27 °C and... 

The model experiments of Xu and Rosakis on low-speed impact over sandwich structures were simulated applying cohesive models. The simulation captures qualitatively the main experimental observations. The most relevant correspondence is in the development of the first crack at the interface between the layers, the presence of shear stresses along the interface, which renders the crack shear driven and often inter-sonic, and the transition between interlayer crack growth and intra-layer crack branching. The effects of impact speed and bond shear strength are also investigated and highly satisfactory predictions are obtained. 

Fig.6 Bonding (shearing) strength of interface between SiC coating and C/C composite as a function of sample thicicness...

The temporary maximum joint resistance (bond shear strength) can be calculated by assuming that the adhesive failure shear strain is encountered at the end of the overlap. For a double-lap configuration the maximum load is specified by the lesser of the values given by the following pair of equations (reference 5.30) ... 

Structural adhesives are those having bond shear strength on the order of 1000 psi or greater. This is often sufficient to cause failure of the plastic substrate when the bond is... 

Interlaminar and secondary bond shear strength of structural plastic laminates 1042 ... 

Fig. 2-6 Ulustrates another direct measurement model used to obtain shear and tensile strengths at the interface. The model for the bond shear strength at the end of the fiber is the one that has a constant cross section (Fig. 2-6(A)), while the model for the tensile strength is the necked-down specimen (Fig. 2-6(B)).

Substrate Age of bond Shear strength, Ib/in, of adhesive bonds... 

An Annex to this ISO document provides a design criterion for adhesive bonding. In order to determine the bonded area, a simplified approach based on shear loading is proposed. Shear stresses should be limited to 20% of the nominal bond shear strength, that is, a safety factor of 5. This factor is intended to account for both stress concentrations in real joints and the viscoelastic (time and temperature dependent) nature of adhesives. Shear data values, to be used if test values are not available, are provided, O Table 48.3. 

Adhesive Nominal bond shear strength (MPa) Design shear stress in bonded joint (MPa)... 

Figure 7.10 LDPE bond shear strength after COj pretreatment...

R.J. Gray, Experimental techniques for measuring fibre/matrix interfacial bond shear strength , int, J. Adhesion and Adhesives. 3,1983,197 202. 

Figure 4. LDPE Bond Shear Strength After CO2 Pre-Treatment...

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