When a material is so soft that the cohesive strength (or adhesive strength, in the case of interfacial fracture) exceeds the elastic modulus of the material, we show that a crack will blunt instead of propagating. Large-deformation ­ nite-element model (FEM) simulations of crack initiation, in which the debonding processes are quanti­ ed using a cohesive zone model, are used to support this hy...

A new cohesive zone model is developed in order to study the mechanisms of adhesive and cohesive failures of soft rubbery materials. The fracture energy is estimated here using a strategy similar to that of Lake and Thomas (LT) by considering the dissipation of stored elastic energy followed by the extension and relaxation of polymer chains. The current model, however, departs from that of LT i...

BACKGROUND Detachment of denture acrylic resin artificial teeth from denture base resin is one of the most common problems presented by denture wearers. PURPOSE This study investigated the shear bond strength (SBS) and fracture type of bonding interface of two commercial acrylic teeth (Vipi Dent Plus e Biolux) to two denture base resins (Vipi Cril e Lucitone 550) after immersion in potentiall...

Recent work has shown that muddy sediments are elastic solids through which animals extend burrows by fracture, whereas non-cohesive granular sands fluidize around some burrowers. These different mechanical responses are reflected in the morphologies and behaviours of their respective inhabitants. However, Armandia brevis, a mud-burrowing opheliid polychaete, lacks an expansible anterior consis...

Adhesively bonded joints are commonly used in airframe structures due to their superior strength to weight ratio, lower maintenance cost, and longer service life. The bonded joint reliability is affected by the environmental conditions, such as moisture, temperature, and service environment. In this study, the role of contamination during the bonding process on the joint mechanical integrity is...

Interfacial shear stress transfer of a monolayer graphene on top of a polymer substrate subjected to uniaxial tension was investigated by a cohesive zone model integrated with a shear-lag model. Strain distribution in the graphene flake was found to behave in three stages in general, bonded, damaged, and debonded, as a result of the interfacial stress transfer. By fitting the cohesive-shear-lag...

Tapered-double cantilever-beam joints were manufactured from aluminium-alloy substrates bonded together using a single-part, rubber-toughened, epoxy adhesive. The mode I fracture behaviour of the joints was investigated as a function of loading rate by conducting a series of tests at crosshead speeds ranging from 3.33 x10 m/s to 13.5 m/s. Unstable, (i.e. stick-slip crack) growth behaviour was o...

Cohesive Modeling of the Deformation and Fracture of Weldbonded Joints M. N. Cavalli, M.D. Thouless and Q.D. Yang Mechanical Engineering Department Materials Science and Engineering Department University of Michigan Ann Arbor, MI Rockwell Scientific Company Thousand Oaks, CA Abstract In previous work, cohesive-zone models have been developed separately for the analysis of adhesively-bonded join...

The main characteristics of the cohesive (or fictitious) crack model, which is now generally accepted as the best simple fracture model for concrete, are (aside from tensile strength) the fracture energies GF and Gf corresponding to the areas under the complete softening stress-separation curve and under the initial tangent of this curve. Although these are two independent fracture characterist...