It is generally accepted that the fatigue crack growth (FCG) depends mainly on the stress intensity factor range (DK) and the maximum stress intensity factor (Kmax). The two parameters are usually combined into one expression called often as the driving force and many various driving forces have been proposed up to date. The driving force can be successful as long as the stress intensity factor...

There exist two fracture mechanisms in facesheets of sandwich composites consisting of the 08 and 908 plies, namely crack growth and crack blocking. The former is undesired since it may lead to failure of facesheets and even the core in sandwich composites. A shear-lag model is developed in this article and it gives a simple criterion governing these two mechanisms. It is established that, for ...

The growth of a single cylindrical hole ahead of a blunt crack tip was studied using large deformation finite element analysis in three-point bend specimens with different precrack depth. The effect of small second phase particles was taken into account by incorporating Gurson’s constitutive equation. The effects of strain hardening and the initial distance from the hole to the crack tip were a...

The propagation of cracks in graded materials under monotonic and cyclic loading was investigated via experiment and simulation. Graded alumina/epoxy composite specimens exhibiting a variation in composition from 5% to 65% epoxy, representing a twenty-fold variation in Young’s modulus, across a region of width between 6 and 20 mm, were produced by a multistep infiltration technique. Crack initi...

In this work, fracture behavior of multilayered unidirectional graphite/epoxy composite (T800/3900-2) materials is investigated. Rectangular coupons with a single-edged notch are studied under geometrically symmetric loading configurations and impact loading conditions. The notch orientation parallel to or at an angle to the fiber orientation is considered to produce mode-I or mixed-mode (mode-...

fast fracture is one of the major failure modes in brittle polymers. generally, crack growth in these polymers may occur under combined tensile-shear loading. however, the fracture test data reported previously for some dental restorative resins can not be predicted by using the available fracture criteria.in this paper, a modified fracture criterion is used for estimating the fracture load for...

The influence of tubule orientation on the transition from fatigue to fatigue crack growth in human dentin was examined. Compact tension (CT) and rectangular beam specimens were prepared from the coronal dentin of molars with three unique tubule orientations (i.e., 0 degrees , 45 degrees and 90 degrees). The CT specimens (N=25) were used to characterize fatigue crack initiation and steady-state...

The structural integrity of oxide/metal interfaces is important in many applications. While most attention has focused on the debonding of oxide/metal interfaces by conducting strength and fracture toughness tests, very few investigations have looked at time dependant failure of interfaces under cyclic or static loading. Tests have been conducted on sandwich specimens consisting of 5 100 micron...

The role of metal layer thickness and resultant plastic constraint in the metal layer during the failure of metal/ceramic layered structures is examined under cyclic and static loading conditions. Crack-growth experiments were conducted on sandwich specimens consisting of 99.999% pure aluminum layers bonded between 99.5% pure polycrystalline alumina with the metal layer thickness varying from 5...

The mean and the life-limiting behavior under fatigue of the nickel-based superalloy, IN100, separated (or converged) as a function of stress level and dwell loading. This behavior was related to the control of the life-limiting behavior by the smallcrack growth regime, producing its much slower response to stress level and dwell-time, relative to the mean-lifetime behavior. The lifetime probab...