Nt1330 Final Exam
ME 3210
Woodruff School of Mechanical Engineering
Georgia Institute of Technology
Design, Materials, and Manufacture
1st Midterm Examination
Fall 2013
Note that multiple choices do NOT offer partial credits; check your calculations carefully.
1. Epoxy has density of 1.25 g/cm3 and elastic modulus of 4 GPa while Kevlar–49 has density of
1.5 g/cm3 and elastic modulus of 120 GPa. If a kelvar-49-reinforced epoxy composite is to have a transverse elastic modulus of 6.5 GPa, what should be its fiber volume fraction? (a) 65%, (b)
50%, (c) 40%, (d) 25%, (e) 10%. (3 points)
Your Answer: ___________
2. Which of the following regarding SPC is/are INCORRECT? (a) If the measuring resolution is
15% of the specified tolerance, the measurement …show more content…
(3 points)
Your Answer: ____________ Gas
Crucible
Induction coil (for heating)
Melt
Strip (final product)
Copper disk
5. As a 10-kg of AISI1040 steel (plain carbon steel with 0.4% carbon) is cooled to 728oC, which statement is/are INCORRECT: (a) There is 5.05-kg austenite (); (b) There is 4.95-kg ferrite
(); (c) There is a 1.25-kg cementite (Fe3C); (d) The alloy is in a three-phase field of
Fe3C; (e) The alloy is 100% solid. (3 points)
Your Answer: ____________
6. An ellipsoid with major axes of 2", 3" and 4" is to be die cast in a graphite mold. The mold has a specific weight of 350 lbf/ft3 and outer dimensions of 6" by 6" by 6" as shown in the figure.
Note that the parting line of the mold lies on the plane of maximum cross-section of the casting.
In this case a clamping force of 7.3 lbf is needed to keep the mold haves from separation.
Being a tooling engineer, you are asked to re-design the depth of the mold so that there is no need for clamping force in casting this part. Please be aware that you do not have the flexibility to modify either the height or the width of the mold. What should be the minimum new depth?
(a) 7”, (b) 8”, (c) 9”, (d) 10”, (e) 11”. (4
Woodruff School of Mechanical Engineering
Georgia Institute of Technology
Design, Materials, and Manufacture
1st Midterm Examination
Fall 2013
Note that multiple choices do NOT offer partial credits; check your calculations carefully.
1. Epoxy has density of 1.25 g/cm3 and elastic modulus of 4 GPa while Kevlar–49 has density of
1.5 g/cm3 and elastic modulus of 120 GPa. If a kelvar-49-reinforced epoxy composite is to have a transverse elastic modulus of 6.5 GPa, what should be its fiber volume fraction? (a) 65%, (b)
50%, (c) 40%, (d) 25%, (e) 10%. (3 points)
Your Answer: ___________
2. Which of the following regarding SPC is/are INCORRECT? (a) If the measuring resolution is
15% of the specified tolerance, the measurement …show more content…
(3 points)
Your Answer: ____________ Gas
Crucible
Induction coil (for heating)
Melt
Strip (final product)
Copper disk
5. As a 10-kg of AISI1040 steel (plain carbon steel with 0.4% carbon) is cooled to 728oC, which statement is/are INCORRECT: (a) There is 5.05-kg austenite (); (b) There is 4.95-kg ferrite
(); (c) There is a 1.25-kg cementite (Fe3C); (d) The alloy is in a three-phase field of
Fe3C; (e) The alloy is 100% solid. (3 points)
Your Answer: ____________
6. An ellipsoid with major axes of 2", 3" and 4" is to be die cast in a graphite mold. The mold has a specific weight of 350 lbf/ft3 and outer dimensions of 6" by 6" by 6" as shown in the figure.
Note that the parting line of the mold lies on the plane of maximum cross-section of the casting.
In this case a clamping force of 7.3 lbf is needed to keep the mold haves from separation.
Being a tooling engineer, you are asked to re-design the depth of the mold so that there is no need for clamping force in casting this part. Please be aware that you do not have the flexibility to modify either the height or the width of the mold. What should be the minimum new depth?
(a) 7”, (b) 8”, (c) 9”, (d) 10”, (e) 11”. (4