MatE271
HW #7
Due Wednesday 11/14/2001 in class WITH THE EXAM
If you can not get it done, you may opt to hand it to any of the secretaries in 1200 Howe
hall, by NOON-Friday
Remember your second exam on Wednesday, Nov. 14
Material Behavior- Mechanical Failure
total 15 points
1. Write in 100 words or less about a failed system or component due to excessive
plastic deformation, fracture, fatigue, creep, or stress relaxation. The component
could be an electrical mechanical, thermal, magnetic, optical or electronic device.
DO NOT write about any case from your textbook. Check any relevant references
from the library, the web, or your other courses, or draw on your own experience.
In your summary, you have to illustrate:
- How did the part fail?
- How did the microstructure played a role
- Please include relevant pictures and references
Possible sources (any fracture mechanics book, Fatigue of materials by S. Suresh)
2. Under what conditions a material can be exposed to fatigue, creep, and relaxation.
Use suitable plots of to illustrate the relation among stress, strain and time.
3. Explain the role of grain size in controlling each of the following mechanical quantities
and the preferred size:
- Metal Strength
- Metal stiffness
- Impact resistance
- Fatigue
- Creep
4. Problem 8.4, P 301
5. Problem 8.9, P 301
6. Problem 8.23, P 302
7. Problem 8.26, P302