4. The following data were obtained from a creep test for aspecimen having an
initial gage length of 2.0 in. and an initial diameter of 0.6in. The initial stress
applied to the material is 10,000 psi. The diameter of thespecimen after fracture
is 0.52 in.
Length Between Gage Marks ( (in.) | Time (h) | Strain (in./in.) |
2.004 | 0 | 0.002 |
2.01 | 100 | 0.004 |
2.02 | 200 | 0.006 |
2.03 | 400 | 0.008 |
2.045 | 1000 | 0.012 |
2.075 | 2000 | 0.020 |
2.135 | 4000 | 0.035 |
2.193 | 6000 | 0.050 |
2.23 | 7000 | 0.070 |
2.30 | 7200 (fracture) | 0.078 |
Determine:
- The load (lbf) applied to the specimen during thetest
- The approximate length of time (h) during which linear creepoccurs
- The creep rate in in./in. h and %/h, and
- The true stress acting on the specimen at the time ofrupture
