The shape of the brick gets deformed due to rain water falling on hot brick. This defect is known as (a) chuffs (c) nodules (b) bloating (d) lamination

Composite _________ is produced by laying fibers in random directions in a plane.

The frame of a space shuttle type vehicle must have a high yield strength and high stillness, and the most important design factor is weight. Of all the materials presented in this chapter, what material might be the most suitable for the frame of a space shuttle? Assume that there will be both tensile and compressive stresses. For a space shuttle, cost is not a limiting factor. (a) You can eliminate entire classes of materials from consideration with a brief statement about their unsuitability. (b) What material has the highest specific yield strength? Give the yield strength, specific gravity, specific yield strength, elastic modulus, and specific elastic modulus for this material. (c) What material has the highest specific elastic modulus? Give the yield strength, specific gravity, specific yield strength, elastic modulus, and specific elastic modulus for this material. (d) Compare the materials with the highest specific yield strength and highest specific elastic modulus for suitability in the space shuttle frame. (C) Discuss the suitability of the top-rated material for this design from the viewpoint of the ability to produce a frame.

In Example Problem 12.1, a uniaxial composite material is made into a circular rod Vbith a 1.27-cm diameter from 70 volume percent continuous carbon fibers and 30 volume percent epoxy. The rod is subject to an axial force of 100,000 N. The composite matcrial in Example Problem 12.1 is to be replaced with a less expensive composite made of 70 volume percent continuous E-glass fibers and 30 volume percent epoxy. The elastic moduli are 5 GPa for the epoxy resin and 72.4 GPa fos the E-glass. (a) Compare the elastic modulus, composite strain, fiber and matrix stresses, and density of this composite with the carbon epoxy composite in Example Problem 12.1. Usc the density of UHM carbon, and assume the density of the epoxy is 1.2g/cm3 . (b) Can both the E-glass fiber and matrix withstand the applied force?