The numerical study of the fatigue behaviour steel and light alloy substrates when coated with thin hard coatings is limited. This paper aims to investigate failure mechanism coating system by observing initiation propagation cracks within under cyclic loading. model composed three layers: TiN coating, a case-hardened diffusion zone H11 substrate. cohesive elements were arranged evenly in horiz...

The low-cycle fatigue behaviour of quasi-brittle materials (e.g., concrete and rock) that is characterized by induced inelastic deformation significantly affects the integrity serviceability engineering structures. However, mechanism fatigue-controlled fracture process not clear. This paper develops a new cyclic cohesive zone model (CZM) for materials. Based on in-situ stress damage state, nonl...

Numerical simulations of crack initiation which use a cohesive zone law to model a weak interface in the solid are often limited by the occurrence of an elastic snap-back instability. At the point of instability, quasi-static finite element computations are unable to converge to an equilibrium solution, which usually terminates the calculation and makes it impossible to follow the postinstabili...

A new experimental technique is developed to determine the onset and evolution of delamination in fiber-reinforced composites under impact loading. The configuration uses a split-Hopkinson bar for low-velocity impact loading and two Polytec laser vibrometer systems for real-time monitoring of the initiation and progression of delamination. The experiment allows the histories of load, displaceme...

Abstract. A new approach to irreversible quasistatic fracture growth is given, by means of Young measures. The study concerns a cohesive zone model with prescribed crack path, when the material gives different responses to loading and unloading phases. In the particular situation of constant unloading response, the result contained in [6] is recovered. In this case, the convergence of the discr...

The cohesive energy of condensed matter in strong magnetic fields is a fundamental quantity characterizing magnetized neutron star surfaces. The cohesive energy refers to the energy required to pull an atom out of the bulk condensed matter at zero pressure. Theoretical models of pulsar and magnetar magnetospheres depend on the cohesive properties of the surface matter in strong magnetic fields....

Abstract. The existence of crack evolutions based on critical points of the energy functional is proved, in the case of a cohesive zone model with prescribed crack path. It turns out that evolutions of this type satisfy a maximum stress criterion for the crack initiation. With an explicit example, it is shown that evolutions based on the absolute minimization of the energy functional do not enj...

While toughening and damage might seem to be two contradictory concepts for the mechanics of crack growth, they are actually the same phenomena perceived from two different vantage points. Similarly, the concepts of extrinsic and intrinsic toughening, defined in terms of whether a toughening mechanism occurs behind or ahead of a crack, depend on the definition of a crack tip that, in the absenc...

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...