Showing papers in "Composites Science and Technology in 1994"

TL;DR: In this paper, the authors give an overview of stitching techniques, which can provide through-thickness reinforcement of a traditional 2D laminate, thus improving its resistance to delamination.

TL;DR: In this article, the damage mechanisms of four short-glass-fibre-reinforced polypropylenes are investigated in tensile, tensile fatigue and crack propagation tests.

TL;DR: In this paper, a second-order intensity function and the Dirichlet tessellation have been used to characterize the spatial dispersion of fibers, and a simple micro-mechanical model illustrates the influence of distribution statistics on the calculated stress field.

TL;DR: In this paper, a load jig is presented which allows mixed-mode fracture testing of adhesive joints and composite laminates over the entire range from mode I to mode II, by using a single equal adherend double-cantilever-beam specimen.

TL;DR: In this paper, two simple micromechanics-based models have been proposed to study the effect of through-thickness reinforcement (stitching) in improving the delamination crack growth resistance double-cantilever beam specimens.

TL;DR: In this paper, a simple shear-lag stress analysis was extended to the laminates containing delaminations at the tips of transverse cracks, and the relationship between the measured material damage and Young's modulus reduction was compared with experimental data.

TL;DR: In this article, the properties of SiC composites reinforced with Nicalon have been investigated and a lowoxygen-content SiC fiber referred to as Hi-Nicalon has been developed for ultra-high temperature use.

TL;DR: In this paper, the in-situ strength of the bondline can be characterized by the fracture envelope (critical energy release rate as a function of the mode of loading), for a specific adhesive system.

TL;DR: In this paper, the authors measured the thermal expansion of various fiber- and particle-reinforced metal-matrix composites and the experimentally obtained values compared with the predictions of various theoretical models, and observed behavior of these particulate and fibrous composites is described on the basis of the thermal stresses developed in such composites as a result of the differences in the coefficient of thermal expansion between the reinforcement and the matrix.

TL;DR: In this article, a linear elastic analysis of a single broken fiber surrounded by six equally spaced fibres is performed, and the analysis shows that the stress concentration in the adjacent fiber is 1·058, much lower than the value of 1·104 predicted by Hedgepeth and van Dyke (J. Comp. Mater., 1 (1967) 294-309).

TL;DR: A new electrical resistance technique is considered for detecting failure in balanced (± θs) angle-ply carbon fiber reinforced plastic materials (CFRP) under high strain-rate tensile testing.

TL;DR: In this paper, the microscopic failure processes in three different types of cross-ply laminates, (0/90n/0)(n = 4, 8, 12), were investigated at room temperature and 80°C.

TL;DR: In this article, the basic elasticity relationship for unidirectional composites, together with the Adams-Bacon damping criterion, are used for prediction of moduli and flexural damping of anisotropic CFRP and GRP beams with respect to fiber orientation.

TL;DR: In this article, an ultrasonic method has been applied for a comparative analysis of the damage detected after static indentation and after low-velocity impact on a composite with quasi-isotropic lay-up.

TL;DR: In this paper, the authors show that extensive fibre bridging, pull-out and fracture of the chopped Kevlar fibres have occurred during delamination, which is a very beneficial side effect and an important factor for the toughness improvement.

TL;DR: In this article, the interfacial shear strength of high-modulus PAN and mesophase pitch-based (P55) carbon fibres and an epoxy matrix has been studied by using the conventional fragmentation test in conjunction with polarised-light optical microscopy.

TL;DR: In this paper, the authors present a review of the status of the fragmentation test and especially the modelling of the test, and the limits of one-dimensional models are defined and the quality of bidimensional models is outlined.

TL;DR: In this article, an analysis method for the description of yarn structures in 3-D braided preforms is presented, where the general topology of the yarn structure in the preform is determined on the basis of the braiding procedure alone.

TL;DR: In this article, it was shown that mechanical compression behavior in the fiber direction for laminated carbon/epoxy structure can be predicted with an elastic non-linear model, and a specific bending test has been developed.

TL;DR: In this article, the effect of fiber misalignment and non-linear behavior of the matrix on fiber microbuckling and the compressive strength of a unidirectional fiber composite was made.

TL;DR: In this article, the authors present an overview of the issues, property status, and potential for use of creep-prone polycrystalline ceramic fibers in thermostructural ceramic composites.

TL;DR: The tensile behavior of knitted carbon-fibre-fabric/epoxy laminates was studied by the use of acoustic emission, optical microscopy and scanning electron microscopy techniques as mentioned in this paper.

TL;DR: In this article, the coordination of fiber fractures for each system was studied as a function of interfiber spacing, and it was shown that fiber fracture occurred in a random pattern when fiber spacing was more than eight fiber diameters.

TL;DR: In this paper, a simple and approximate approach is proposed for the prediction of progressive stiffness loss, matrix-crack density, and delamination area in terms of tension-tension fatigue load and number of cycles for general composite laminates containing 0° plies.

TL;DR: In this article, a comparative study of the in-plane shear behavior of the AS4/PEEK thermoplastic and the thermoset T300/914 material is presented.

TL;DR: In this paper, the means by which residual stresses are generated in continuous carbon-fibre-reinforced thermoplastic composites are reviewed, with specific attention to the macroscopic stresses which form on a ply-to-ply level.

TL;DR: In this article, fly-ash to 20 wt% was added to polypropylene and an ethylene/propylene copolymer with and without the addition of a maleic anhydride grafted poly-propylene coupling agent.

TL;DR: In this article, a preceramic-based BN fiber was fabricated by utilizing the pre-ceramic method and the spinnability of the fiber was excellent, in spite of the low molecular weight of the precursor, because it has a structural similarity with melt-spinnable carbon pitch.

TL;DR: Stochastic silicon carbide fibers have been converted to small-diameter, polycrystalline silicon carbides by melt-spinning, cross-linking and pyrolyzing to high-temperature in argon as mentioned in this paper.

TL;DR: In this paper, the elastic modulus and tensile strength of knitted fabric reinforced epoxy laminates were predicted by using a modified rule-of-mixtures law incorporating the efficiency of reinforcement of curved yarn fibres.