Cohesive Fracture Study of a Bonded Coarse Silica Sand Aggregate Bond Interface Subjected to Mixed-Mode Bending Conditions

Abstract

Abstract:One of the primary objectives in the design of composite structures is the prevention of premature bond failure. Therefore, the characterization of cohesive behavior is an important field of study in structural engineering. Using fracture mechanics principles, the cohesive behavior of an epoxy bonded coarse silica sand aggregate bond interface is studied in this paper, with a focus on finding a general analytical form of idealizing its behavior when used in a specimen possessing asymmetric and inhomogeneous qualities. Two series of small-scale specimens were experimentally tested under mixed-mode bending (MMB) conditions, where it was found that there was negligible influence exerted on the fracture energy of the interface due to changes in the mixed-mode ratio or initial crack length. Using finite element analysis (FEA) methods, an appropriate bilinear traction-separation model was developed to both validate as well as obtain a set of consistent parameters applicable to all tested specimens. Comparison of the Global Method and the Local Method, used to obtain partitioned Mode I and Mode II fracture energy values from MMB specimens, were made, with the conclusion that both methods are adequate in the calculation of the total fracture energy though the Local Method should be used to obtain accurate partitioned Mode I and Mode II fracture energy values. Idealization of the bond interface using the cohesive parameters derived can be accurately achieved by the use of both contact interactions and cohesive elements in two-dimensional and three-dimensional FE models, though the results obtained using contact interactions would be expected to exhibit greater global stiffness.

Shear Performance Assessment of Sand-Coated GFRP Perforated Connectors Embedded in Concrete

“…The push/pull-out tests of sand-coated FRP plate/rebar, finite element (FE) simulation is a regular tool to investigate the bond behavior [19]. Cohesive zone modeling (CZM) is one of the most common methods in FE simulation, such as: Chen and EL [20] used CZM to obtain mixed-mode bending fracture energy of the interface between sand-coated GFRP and UHPC; and Tekle et al [21] implemented CZM to investigate strand and bond distribution along the sand-coated GFRP bars. Besides, the tests about the roughness of sand-coated surface have been done to understand its effect on adhesion strength, however, the result showed a scatter about the adhesion resistance and the aggregate size [22,23].…”

A numerical study on the effect of local cohesive property variation to single mode fracture models

“…38 Although various other shapes exist 33,34,39 , a bilinear TSL (see FIGURE 2a) is used in this work due to its simple implementation to FEA models and its common application to delamination processes. 24,40,41 It is decribed via three fracture mode dependend parameters (subscript indicates the associated mode), i.e. the cohesive stiffness , the cohesive strength and the strain energy release ratio (SERR) .…”

On the identification of cohesive parameters for printed metal-polymer interfaces

“…These include, but are not limited to, linear, bilinear, trapezoidal and exponential functions [16]. A bilinear TSL is simple and sufficiently describes many materials [12,14,17,18], making it suitable for fundamental research when mechanical properties are unknown. To describe a TSL as a mathematical curve, coefficients are needed.…”