Effect of the Interfacial Stress Distribution on the Material Interfacial Shear Strength Measurement

Abstract

An integrated experimental and numerical analysis is carried out to study the interfacial shear strength of bonded materials. Two types of shear tests, namely the Iosipescu shear test, and the short-beam shear test are employed to understand the effect of interfacial stress on the interfacial shear strength measurements. The measured average shear strengths are very close, even though the interfacial shear stress distributions of these two kinds of specimens are very different. Therefore, we conclude that the interfacial stress distribution has the least effect on the interfacial strength measurement if the interfacial shear stress is non-singular.

A short-beam shear fracture approach to measure the mode II fracture toughness of materials with preferred interfaces

“…This fixture has been used to characterize the shear strength of short-beam shear specimens; and the average shear strengths are found to be very close to the shear strengths of the Iosipescu shear specimens in spite of very different interfacial shear stress distributions (Krishnan and Xu 2010). In the current investigation, the advantage of having zero interfacial normal stress (zero bending moment) at the specimen center is used to develop an efficient experimental method to determine the mode II fracture toughness of bonded polymers.…”

“…In this investigation, a short-beam shear fracture specimen (Fig. 1b) with a bonded interface is chosen to match those dimensions required for a widely used Iosipescu test fixture (Krishnan and Xu 2010). The short-beam shear fracture test is indeed an asymmetric four-point bend test.…”

“…The loading is applied in the form of loading block on the specimen edges similar to what is observed in reality. In order to incorporate a realistic simulation of the loads on the specimen, an iterative procedure is adopted (Xu et al 2004b;Krishnan and Xu 2010). The loads in the form of displacements are applied to the movable part of the specimen while the other part is held fixed.…”

An experimental study on the crack initiation from notches connected to interfaces of bonded bi-materials

“…The experimental set-up consists of three parts including a mechanical system to apply the bending load on the specimen, an optical system to develop fringe patterns and an imaging system to record the photoelastic fringe patterns and crack propagation (further details in [9]. The loading point S was varied from 0 mm (center) to 30 mm and À30 mm (on either side of the center line) on the top of the specimen.…”

An Integrated Experimental and Numerical analysis on Notch and Interface Interaction in Same-materials

“…But, the problem of crack onset at a notched interface is still an open problem and only a few criterions have been proposed Leguillon, 2002). Recent experiments on composite laminates have indicated that impact-induced delamination will propagate under compressive loading (Krishnan and Xu, 2010). This delamination front is a notch and not a mathematically sharp crack (as shown in Fig.…”