Application of the Paris Equation to the Fatigue Growth of Transverse Ply Cracks

Abstract

A model based on a stress intensity factor for a growing transverse ply crack is outlined. The model is applied to experimental observations of crack growth in a trans parent 0/90/0 glass fibre/epoxy laminate under fatigue loading. The crack growth rate is found to be independent of crack length but to depend on the spacing between cracks. Under static loading and fatigue loading at high maximum stress, cracks grow by fast frac ture. Slow crack growth is observed at lower maximum fatigue stresses and in the later stages of fatigue tests at higher stresses when the crack spacing is small. Crack growth rates can be described using a Paris relation.

Fatigue damage evolution in GFRP laminates with constrained off-axis plies

“…The CGR results are plotted against the computed ERR for an isolated crack front in Figure 10(b). A large variance in the data is observed, and the magnitude of the variance is seen to be approximately the same as found in [25]. The large degree of scatter in the dataset indicates that a single Paris' Law relationship is not sufficient to describe the physics of crack propagation.…”

“…Crack growth rates (CGR) for the stable propagation of off-axis cracks under CA loading with constant load ratio have been reported in [8,9,18,25]. In [8,25] the CGR of off-axis cracks throughout the fatigue test were manually measured and it was found that the CGR were independent of crack length but dependent on stress level and crack density.…”

“…In [8,25] the CGR of off-axis cracks throughout the fatigue test were manually measured and it was found that the CGR were independent of crack length but dependent on stress level and crack density. The CGR increased with increasing stress level and decreased with increasing crack density, where the latter is known as the 'shielding effect' of off-axis cracks [9].…”

Progress in Detecting Transverse Matrix Cracking Using Modal Acoustic Emission

“…The cracks are usually through cracks InF2.ning that they progress rapidly across the entire width of the specimen and it is generally accepted that they are the first failure mode to occur with rising load, beginning as early as 30% of ultimate load. Keen interest in TMC in polymeric composites was found in the mechanics of composites literature through the 1980s [1][2][3][4][5][6][7] and this stimulated measurements ofTMC using acoustic emission techniques.…”

Illustrations of a microdamage model for laminates under oxidizing thermal cycling

“…• as observed classically in fatigue tests ( [17][18][19][20][21]), microcracks develop first near the edge of the sample until saturation of the microcracking rate. Then, cracks propagate from the edge toward the core.…”