Mechanical Metallurgy Practice Test 6

1. Find the mean stress in the given stress cycle?

2. The Coffin-Manson relation is described as ________________
where Δε_p = the plastic strain amplitude
ε’_f = fatigue ductility coefficient
2N = number of strain reversal to failure
c = fatigue ductility exponent

3. Which of the following curve represents the cycle hardening of the material?

4. The point X in the above diagram indicates the ________

5. The geometry of the plastic zone in front of a crack tip is shown in the following figure.

6. When the value of R becomes positive, that indicates the mean stress is becoming _________

7. If the mean stress is zero for any component, then the value of the stress ratio (R) will be equal to _______

8. The following picture is the correct representation of the Goodman diagram. The point X in the given curve indicates the ______________

9. For the evaluation of J-integral value from the compact tension specimen, the amount of J in the below-shown sample is equal to __________
Where A = area under the load vs. displacement curve
b=W-a
B=Specimen thickness

10. A steel bar having diameter 14 m is subjected to a fluctuating load of 50 kN in tension and 10 kN in compression. Find the mean stress of the steel bar?