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Question: background you are a materials engineer working for a railroad...

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Background You are a materials engineer working for a railroad company in Arizona laying track. Your salary is $70,000 a year. An expansion gap is left between rail-ends to prevent the rails from pushing against each other when the temperature rises. If the gap is too small, the track may buckle in hot weather causing a derailment. If the gap is too large, the ride will be bumpy and the ends of the track may be damaged by train wheels when the track contracts in cold weather. The maximum possible rail temperature is 175°F. The length of each piece of rail is 40 feet. The rail cross sectional area is 10 square inches. The temperature of the track at the time of linking is 95 . As a safety factor, even at maximum temperature the rail ends must have a gap of 0.04 inch. The coefficient of linear thermal expansion of 1080 rail steel is equal to 0.0000061 per degree Fahrenheit. The modulus of elasticity of rail steel is 29.7 msi. The yield strength of 1080 steel is 84.8 ksi. Questions You have been asked to a. Calculate the size of the expansion gap between rail ends. b. Calculate the internal stress in a fully restrained rail if the temperature increases 75°F above the c. d. temperature of the track at the time it was linked? Calculate the internal stress in a fully restrained rail if the temperature decreases 75°F below the temperature of the track at the time it was linked, ignoring effects from metal creep. Calculate the internal force in a fully restrained rail if the temperature decreases 75oF below the temperature of the track at the time it was linked, ignoring effects from metal creep

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