This paper presents three analytical models for the investigation of the stiffness and strength of woven fabric composites. The “mosaic model” is effective in predicting the elastic properties of fabric composites. The “fibre undulation model” takes into account fibre continuity and undulation and has been adopted for modelling the “knee behaviour” of plain weave fabric composites. The “bridging model” is developed to simulate the load transfer among the interlaced regions in satin composites. The theoretical predictions coincide extremely well with experimental measurements. The elastic stiffness and knee stress in satin composites are higher than those in plain weave composites due to the presence of the bridging regions in the weaving pattern.

Stiffness and strength behaviour of woven fabric composites

The stress field in a coated continuous fiber composite subjected to thermo- mechanical loadings is calculated by use of four concentric circular cylinders model. The target material is Ni- or SiC-...

Stress Field in a Coated Continuous Fiber Composite Subjected to Thermo-Mechanical Loadings

Composite technology, where a novel artificial material is fabricated by combining, for example, ceramic and polymer materials in an ordered manner or just by mixing, was earlier used widely for sonar, medical diagnostics, and NDT purposes. However, in recent decades, large numbers of ceramic–polymer composites have been introduced for telecommunication and microelectronic applications. For these purposes, composites of 0–3 connectivity (a three-dimensionally connected polymer phase is loaded with isolated ceramic particles) are the most attractive from the application point of view. Composites of 0–3 connectivity enable flexible forms and very different shapes with very inexpensive fabrication methods including simply mixing and molding. In this brief review, we gather together the research carried out within 0–3 ceramic–polymer composites for microwave substrates, also including embedded capacitor, inductor, or microwave-absorbing performances.

Polymer–Ceramic Composites of 0–3 Connectivity for Circuits in Electronics: A Review

One of the most elementary concepts in elasticity theory is that of a uniform state of stress. Producing such a state of stress in the laboratory, however, is not a trivial task. A common experiment in composite mechanics—the tension test of off-angle composites-is discussed in this paper and the influence of end constraint on the uniform stress field is investigated. Analytical and experimental evidence is presented to show the serious effects caused by con ventional clamping devices.

Pagano and Halpin - Influence of End Constraint in the Testing of Anisotropic Bodies

Elastic response of multi-directional coated-fiber composites

An analytical and experimental investigation on thermal expansion coef ficients of unidirectional composites (UD) is carried out. The fiber aniso tropy and temperature dependency of the constituent material properties are considered in the formulation of the problem. The solving technique used here is constructed by a slight modification of the one which was once developed and employed by the authors for calculating elastic moduli of UD. It is shown that αz of UD is approximately given by the modulus modified law of mixture, and that αx's based on the hexagonal and square array models are almost identical. Some relationships between α's of UD and the constituent material properties are graphically indicated. The first point of the main purpose of the experiments is to reveal certain tempera ture dependent behavior of α's of the constituents of the Carbon-Epoxy. The second is a comparison between the experimental and theoretical re sults of an influence of αm on αx and α z. The third is to estimate unknown...

Thermal Expansion Coefficients of Unidirectional Composites

All independent elastic moduli of unidirectional carbon-epoxy com posites were measured in the tensile and torsional tests of co-axis and off-axis specimens. The experiments were motivated to estimate the unmeasurable elastic moduli of carbon fiber itself. The experimental results were incorporated with the authors' preceding analytical results which describe the relationships between the moduli of composites and consti tuents. According to several results, the fact that the hexagonal array packing is more favorable as an idealized model was obtained. It should be noted that carbon fiber is highly anisotropic and that the estimated values of those moduli are reasonable in comparison with those in a few existing references. Some of the basic assumptions employed in the analysis were confirmed by the observation of the transverse and longitudinal sections of the specimens through an electron-scanning-beam microscope (ESM).

Takashi Ishikawa

Papers

Thermal Expansion Coefficients of Unidirectional Composites

Elastic Moduli of Carbon-Epoxy Composites and Carbon Fibers