Showing papers in "Composites Science and Technology in 1991"

TL;DR: In this article, the main features of progressive folding and progressive crushing in tubes subjected to axial compression are summarised, with particular reference to the geometry of the folded or crushed region and the force-displacement response.

TL;DR: A review of fracture toughness of fiber composites can be found in this article, where various methods for improving the fracture toughness by means of interface control are discussed. But, the focus is on the failure mechanisms leading to eventual fracture.

TL;DR: In this paper, the surface of sisal fibres has been modified by mercerization and silane treatment to improve adhesion characteristics and moisture resistance, which is most effective in reducing moisture uptake of fibres in humid environments.

TL;DR: In this article, a brief critical review is presented of research into the nature of the interface in carbon fiber/epoxy matrix composites, and the influence of the interfaces on properties.

TL;DR: In this article, the dominant influence of fiber coatings on the mechanical performance of brittle matrix composites is addressed in terms of two independent mechanical parameters, the debond energy, Γ i, and the sliding resistance, τ.

TL;DR: In this paper, a detailed analysis of the single filament pullout test is presented, which shows that interpretations of pull-out tests are still open to discussion, from which it is emphasized that there is a need for more standardized procedures if comparisons are to be made.

TL;DR: In this paper, a simple micromechanical model is developed to describe the elastic-plastic behavior of fibrous composites, where the fiber is assumed to be linearly elastic, and the matrix elasticplastic following the J 2 -flow rule.

TL;DR: In this article, the application of this technique for performing interfacial studies on model short-and long-fibre composites is reviewed in this paper, where the authors show that by subjecting these composites to various degrees of mechanical deformation a number of parameters, such as the transfer length, the stress transfer efficiency and the initiation of fibre debonding or matrix yielding, can be assessed.

TL;DR: The role of friction in tests used to measure the strength of the fiber-polymer interface is critically examined in this paper, where it is shown that it is very difficult to obtain results that are untainted by friction, and the different tests probably involve different ratios of frictional shears to pure debonding shears.

TL;DR: In this article, the authors modified the ordinary shear lag analysis to introduce the influence of the matrix stiffness, and the tensile stress concentration in the fibers and matrix adjacent to cut fibers were estimated.

TL;DR: In this paper, an experimental study of the compressive failure of T800/924C carbon-fibre/efoxy composite laminates was performed and the critical failure mechanism observed was microbuckling of the 0° plies.

TL;DR: In this paper, the authors examined the mechanical aspects of the microbond pull-out technique for measuring fiber/resin interfacial shear strength and determined the origins of the consistent variability in bond strength results.

TL;DR: In this paper, a study of chamfer-based trigger mechanisms for use with energy-absorbing glass cloth/epoxy composite tubes was made and the resulting microstructures were examined microscopically.

TL;DR: In this article, an experimental method and analysis has been used on double-cantilever beam (DCB) specimens of a carbon-epoxy laminate, using strain gauges and acoustic emission to detect the appearance of microcracking at the crack tip and the onset of delamination growth.

TL;DR: In this article, an improved plasma treatment method was proposed to obtain a greater degree of control over interfacial properties in carbon fiber/epoxy composites, which can be used to improve the interfacial shear strength.

TL;DR: In this paper, a method of determination of the axial Poisson's ratio of single carbon fibres is presented, based on a laser diffractographic technique, with an accuracy of 5·7%.

TL;DR: In this article, a fracture mechanics analysis for the strain energy release rate associated with 90° ply matrix crack formation and growth has been developed and compared with experimental results, where the authors focused on fatigue mechanisms of matrix cracking in carbon/epoxy cross-ply laminates.

TL;DR: In this article, the authors found that up to 100% more energy per unit weight was absorbed by tulip triggered tubes compared with bevel triggered tubes and the morphology of the material in the crushing zone differed in the amount and the pattern of fracture.

TL;DR: In this paper, the effects of injection molding parameters on fiber degradation and fracture performance in PBT-PET blend/glass fiber composites were investigated, i.e., peak cavity pressure, holding pressure, back pressure, screw speed, melt temperature and barrel profile.

TL;DR: In this paper, the effect of fiber and matrix properties as a function of frequency, up to 1000 Hz, on the damping of composites was investigated using both an IBM PC-AT and a GenRad 2500 Series FFT analyzer.

TL;DR: In this article, a fracture mechanics study for two different types of carbon fiber reinforced carbon matrix composites, a short-fiber felt composite and a satin weave laminated-composite, is reported.

TL;DR: In this article, carboxyl-terminated butadiene acrylonitrile (CTBN) and polyurethane (PU) resins were used as interleaf materials for toughening graphite/epoxy composites.

TL;DR: In this article, it was shown that the fracture energy of E-glass and carbon fiber reinforced polymer composites can be characterized by a fragment length distribution, and that the mode of failure in most instances can be characterised by a fracture energy criterion.

TL;DR: In this article, a survey of the principles underlying the design of model interface microstructures which have the required micromechanical response and thermal or environmental stability within fiber-reinforced ceramic matrix composites is presented.

TL;DR: In this paper, a higher-order deformation theory was derived for the thermal buckling analysis of antisymmetric angle-ply laminates that are simply supported and subject to a uniform temperature rise.

TL;DR: In this article, a new model describing the notched strength of carbon fiber composites has been developed with the aid of linear elastic fracture mechanics, and a function relating split length to applied stress for (90/0) s laminates has been derived.

TL;DR: In this article, a three-dimensional finite element method is developed for the characterization of the effects of three dimensional states of stress on the damping of laminated composites, where the effect of interlaminar stresses on laminate damping is studied by varying the fiber orientation and the laminate width-to-thickness ratio.

TL;DR: In this paper, the importance of different types of stress relaxation procesess is emphasised, and some observations about testing procedures designed to measure bond strength in MMCs are presented.