Chapter 16: Problem 22
(a) List four reasons why glass fibers are most commonly used for reinforcement. (b) Why is the surface perfection of glass fibers so important? (c) What measures are taken to protect the surface of glass fibers?
/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none}
Learning Materials
Features
Discover
Chapter 16: Problem 22
(a) List four reasons why glass fibers are most commonly used for reinforcement. (b) Why is the surface perfection of glass fibers so important? (c) What measures are taken to protect the surface of glass fibers?
All the tools & learning materials you need for study success - in one app.
Get started for free
A large-particle composite consisting of tungsten particles within a copper matrix is to be prepared. If the volume fractions of tungsten and copper are 0.70 and \(0.30,\) respectively, estimate the upper limit for the specific stiffness of this composite given the data that follow. $$\begin{array}{lcc}\hline & \begin{array}{c}\text {Specific} \\\\\text {Gravity}\end{array} & \begin{array}{c}\text {Modulus of} \\\\\text {Elasticity (GPa)}\end{array} \\\\\hline \text { Copper } & 8.9 & 110 \\\\\text { Tungsten } & 19.3 &407 \\\\\hline\end{array}$$.
The mechanical properties of cobalt may be improved by incorporating fine particles of tungsten carbide (WC). Given that the moduli of elasticity of these materials are, respectively, \(200 \mathrm{GPa}\) \(\left(30 \times 10^{6} \mathrm{psi}\right)\) and \(700 \mathrm{GPa}\left(102 \times 10^{6} \mathrm{psi}\right)\), plot the modulus of elasticity versus the volume percent of WC in Co from 0 to 100 vol \(\%\), using both upperand lower- bound expressions.
For a continuous and oriented fiber-reinforced composite, the moduli of elasticity in the longitudinal and transverse directions are \(33.1\) and \(3.66\) GPa ( \(4.8 \times 10^{6}\) and \(\left.5.3 \times 10^{5} \mathrm{psi}\right)\), respectively. If the volume fraction of fibers is \(0.30\), determine the moduli of elasticity of fiber and matrix phases.
Is it possible to produce a continuous and oriented aramid fiber-epoxy matrix composite having longitudinal and transverse moduli of elasticity of \(35 \mathrm{GPa}\left(5 \times 10^{6} \mathrm{psi}\right)\) and \(5.17 \mathrm{GPa}(7.5 \times\) \(10^{5} \mathrm{psi}\) ), respectively? Why or why not? Assume that the elastic modulus of the epoxy is \(3.4 \mathrm{GPa}\) \(\left(4.93 \times 10^{5} \mathrm{psi}\right)\)
(a) For a fiber-reinforced composite, the efficiency of reinforcement \(\eta\) depends on fiber length \(l\) according to $$ \eta=\frac{l-2 x}{l} $$ where \(x\) represents the length of the fiber at each end that does not contribute to the load transfer. Make a plot of \(\eta\) versus \(l\) to \(l=50 \mathrm{~mm}\) (2.0 in.), assuming that \(x=1.25 \mathrm{~mm}(0.05 \mathrm{in} .)\). (b) What length is required for a \(0.90\) efficiency of reinforcement?
What do you think about this solution?
We value your feedback to improve our textbook solutions.