A shear-lag analysis based on energy is used to predict the amount of debonding that occurs when a fiber fragment breaks into two fragments. The shear-lag analysis reproduces all features of more sophisticated analyses. A drawback of the shear-lag analysis, however, is that it depends on an unknown parameter which can be expressed in terms of an effective fiber volume fraction. If the effective...

The debonding of Pressure Sensitive Adhesives (PSA) is a classical example of the difficult and unsolved issue of fracture in soft viscoelastic confined materials. The presence of a complex debonding region where the adhesive undergoes cavitation and the very large strain of a spontaneously formed fibrillar network has defied many modeling attempts over the past 70 years. We present here a nove...

OBJECTIVE To evaluate the influence of bonding and debonding of orthodontic brackets on dental in-home bleaching, taking into account three different adhesive systems. METHODS Forty-four bovine incisors were divided into four groups according to the primer system used for orthodontic bracket bonding. Following the debonding of orthodontic brackets, the teeth were stored in staining solution f...

This research program is intended to verify the influence of using distributed external U-wrap CFRP anchorage to shift the failure mode from overall debonding to sectional flexural failure for concrete beams externally bonded with CFRP sheets. Premature cover delamination and FRP debonding are predominant failure modes in FRP flexural strengthening that may be delayed or prevented by using FRP ...

Accurate measurement of interfacial properties is critical any time two materials are bonded--in composites, tooth crowns, or when biomaterials are attached to the human body. Yet, in spite of this importance, reliable methods to measure interfacial properties between dissimilar materials remain elusive. Here we present an experimental approach to quantify the interfacial fracture energy Γi tha...

in this paper, a systematic study on the effects of particle size and hybrid of two different size of silica nanoparticles on the toughening mechanisms of bisphenol-a epoxy was conducted. nanosilica particles with mean diameter of 17 nm and 65 nm were blended into epoxy system. probable synergy effects of these two nanoparticles on young’s modulus and yield strength have been investigated. resu...

Debonding of films attached to substrates as well as fibers embedded in matrices typically involves initiation, steady-state propagation and a final transient as the debond converges on an edge or another debond. The emphasis in this paper is on the mechanics of the transient. Under most circumstances, a converging debond crack is characterized by an energy release rate that approaches zero, ca...

Damage evolution in heterogeneous solids is modeled using transformation field analysis and imperfect interface model. Stress changes caused by local debonding are simulated by residual stresses generated by equivalent transformation strains or eigenstrains. Decohesion and both overall and local stress and strain rates are derived from thermodynamics of irreversible processes, which provide an ...

This study focuses on the optimizing the microstructure to improve the efficiency for healing interfacial debonding in fiber-reinforced polymers (FRPs). Healing is accomplished by incorporating a microcapsulated healing agent and catalytic chemical trigger within a coating layer on the surface of the fiber strands. Self-healing is demonstrated on flat tensile specimens of unidirectional FRPs. T...