Meen 222- Quiz 7

# Meen 222- Quiz 7 - Modulus of elasticity, Tensile Strength...

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Charles Goodyear (December 29, 1800 - July 1, 1860) was the first American to vulcanize rubber, a process which he discovered in 1839 and patented on June 15, 1844. Although Goodyear is often credited with its invention, modern evidence has proven that the Mesoamericans used stabilized rubber for balls and other objects as early as 1600 BC. Goodyear discovered the vulcanization process accidentally after five years of research. In 1898, after his death, the Goodyear Tire and Rubber Company was founded and named after Goodyear by Frank Seiberling. MEEN 222 – 503 Fall 2008 Quiz #7 Student: Print First and Last Name

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1. The logarithm of relaxation modulus E(t) vs. the logarithm of time is plotted for PMMA at the variety on temperatures. Make a plot of log E(10) vs. temperature and then estimate glass transition temperature. 2. A continuous and aligned fiber-reinforced composite is to be produced consisting of 45vol% aramid fibers and 55vol% of polycarbonate matrix; mechanical properties of those two materials are as follows:
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Unformatted text preview: Modulus of elasticity, Tensile Strength GPa MPa Aramid fiber 131 3600 Polycarbonate 2.4 65 Also, the stress at the polycarbonate matrix when aramid fibers fail is 35 Mpa. For this composite compute (a) longitudinal tensile strength and (b) the longitudinal modulus of elasticity. 3. Relaxation modulus of the polymer increases significantly at glass transition temperature (circle the correct answer). TRUE / FALSE 4. The magnitude of the modulus of elasticity decreases with increasing porosity of ceramics (circle the correct answer). TRUE / FALSE 1E-3 0.01 0.1 1 10 100 1000 0.01 0.1 1 10 100 1000 10000 40 60 80 100 120 140 160 0.01 0.1 1 10 100 1000 10000 Relaxation modulus E(10), MPa Time, h Relaxation modulus E(t), MPa Time, h 40 o C 60 o C 80 o C 110 o C 115 o C 125 o C 140 o C 150 o C Temperature, o C T g is approximately at 97 o C 1 point for curve 1 point showing how the curve is constructed 1 point 1 point 1 point...
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## Meen 222- Quiz 7 - Modulus of elasticity, Tensile Strength...

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