Designing with composites

Designing with composites materials for violin bodies... 

Lucien A. Schmit, The Structural Synthesis Concept and Its Potential Role in Design with Composites, in Mechanics of Composite Materials, Proceedings of the Sth Symposium on Naval Structural Mechanics, F. W. Wendt, H. Llebowitz, and N. Perrone (Editors), Philadelphia, Pennsylvania, 8-10 May 1967, Pergamon, New York, 1970, pp. 553-582. 

Designing with composites, as with any other material, is a combination of art and science. The creative element of the design process is often associated with shape, geometry, colour and surface texture, that is with the visual and tactile attributes of the structure or component. Beneath the surface are the technical aspects of the design the choice of materials, their properties, loads, failure criteria, fabrication and processing methods. 

In design with composite materials the engineer must be able to work back and forth through these three levels of analysis in order to select the best constituent materials for composite layers and to arrange the layer with the desired orientation and stacking sequence to achieve the optimum response of a laminated structure for a given loading environment. 

Figure 15.3 Evaporator design with the help of the grand composite curve. (From Smith and Linnhoff, Trans. ICkemE, ChERD, 66 195, 1988 reproduced by permission of the Institution of Chemical Engineers.)...

There is one obvious drawback of high-hysteresis rubber. In normal rolling operation, considerable elastic deformations still take place in the tyre wall, and high-loss tyres will consume fuel and generate considerable heat. The way out is to use a low-loss tyre covered with a high-loss tread - another example of design using composite materials (Fig. 26.9). 

D. Designing with metals, ceramics, polymers and composites... 

Composites fabricated with fixed catalyst VGCF can be designed with fibers oriented in preferred directions to produce desired combinations of thermal conductivity and coefficient of thermal expansion. While such composites are not likely to be cost-competitive with metals in the near future, the ability to design for thermal conductivity in preferred directions, combined with lower density and lower coefficient of thermal expansion, could warrant the use of such VGCF composites in less price sensitive applications, such as electronics for aerospace vehicles. 

The value of W calculated from the gas composition or from Equation 5 should be considered to be a minimum requirement. A multijet flare should be designed with a calculated air capacity as high as possible, as limited by practical limitations of economics and geometry. 

Phillips, L.N. (ed.) Design with Advanced Composite Materials, Design Council, London (1989). Strong, B.A. High Performance Engineering Thermoplastic Composites, Technomic Lancaster, PA (1993). 

For the composite spoiler design, the bottom is a variable-thickness skin on one side in Figure 1-33, but with composite materials that construction is not difficult. We do not have to chem-mill a composite material to change its thickness. All we do is stop building up the material in layers in the middle, but continue to build it up at the sides. That s a very natural process for composite materials and does not involve a costly machining operation. Instead of machined extruded stiffeners, a honeycomb core is placed on the inside of the laminae. That honeycomb... 

The term r Vf in Equation (3.71) can be interpreted as a reduced fiber-volume fraction. The word reduced is used because q 1. Moreover, it is apparent from Equation (3.72) that r is affected by the constituent material properties as well as by the reinforcement geometry factor To further assist in gaining appreciation of the Halpin-Tsai equations, the basic equation. Equation (3.71), is plotted in Figure 3-39 as a function of qV,. Curves with intermediate values of can be quickly generated. Note that all curves approach infinity as qVf approaches one. Obviously, practical values of qV, are less than about. 6, but most curves are shown in Figure 3-39 for values up to about. 9. Such master curves for various vaiues of can be used in design of composite materiais. 

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