Fracture of Boron/Aluminum Composites with Discontinuities

Abstract

Boron/aluminum laminates in symmetric layups of [±45] and [±45/02] containing discontinuities in the form of holes and slits were tested in tension. Both layups exhibited decreases in failure stress with discontinuity size. However the two exhibited quite different failure modes. The [±45 ] failed with interlaminar shear as the dominant mode whereas the [±45/02] specimens reacted to discontinuities catastrophically in a manner suggestive of the effect of cracks on homogeneous metals. A correlation is proposed for the fracture of the [±45/02] laminate.

Damage Tolerance and Arrest Characteristics of Pressurized Graphite/Epoxy Tape Cylinders

“…The methods described below were chosen because they are representative of the different approaches to notched coupon fracture prediction/correlation, and because they have been shown to be good correlative models for coupon fracture stresses. The first method presented, developed by Mar and Lin [9], is similar in expression to linear elastic fracture mechanics but includes a factor accounting for the inhomogeneity of the material. The second, proposed by Whitney and Nuismer [10,11], is used to correlate fracture stresses by quantifying the local stress state surrounding the notch tip.…”

“…Mar and Lin describe the fracture stress of a notched coupon under uniaxial tension in a manner analagous to linear elastic fracture mechanics [9]. They proposed that the far-field fracture stress can be expressed in the form…”

Fracture Behavior of Boron Aluminum Composites at Room and Elevated Temperatures.

“…Mar and Lin (ML-model) [12,58,59], is to assume: Table V. It can be seen from Figure 26 that Equation (13) represents the data quite closely.…”

Durability-Based Design Criteria for a Quasi-Isotropic Carbon-Fiber Automotive Composite

“…Several investigators have shown that the length of a discontinuity, not its shape, is the governing parameter, at least in fiber-dominated layups. [27][28][29] Thus, holes can be used to characterize the effect of other discontinuities, including slits. Further, it is shown in Chap.…”