MCQOPTIONS
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MCQOPTIONS
This section includes 10 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Metallurgy knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A copper plate with an initial crack length of 30 mm is subjected to the stress of 500 MPa normal to crack. If the yield strength of the copper is 1000 MPa, Find the plastic zone size? Assume the plate is infinity wide. |
| A. | 1.19 mm |
| B. | 2.1 mm |
| C. | 3.5 mm |
| D. | 10 mm |
| Answer» B. 2.1 mm | |
| 2. |
According to Irwin’s correction of plasticity at the crack tip, the effective crack length is given as the actual crack length plus the radius of the plastic zone. The radius of the plastic zone (rp) in case of plane strain is given as ________ |
| A. | rp=1/2 K2/σo2 |
| B. | rp=1/6 K2/πσo2 |
| C. | rp=1/8 K2/σo |
| D. | rp=1/2 K/σo |
| Answer» C. rp=1/8 K2/σo | |
| 3. |
According to Irwin’s correction of plasticity at the crack tip, the sufficient crack length is given as the actual crack length plus the radius of the plastic zone. The radius of the plastic zone (rp) in case of plane stress is given as ________ |
| A. | rp=1/2 K2/σo2 |
| B. | rp=1/2 K2/πσo2 |
| C. | rp=1/2 K2/σo |
| D. | rp=1/2 K/σo |
| Answer» C. rp=1/2 K2/σo | |
| 4. |
Load vs. notch displacement curve for very brittle elastic material is given by the following curve. |
| A. | True |
| B. | False |
| Answer» C. | |
| 5. |
The fracture toughness of the material is given as 25 MPa m1/2, and the yield strength is equal to 600 MPa. Find the minimum thickness of the material to achieve the condition of plane strain? |
| A. | 5 mm |
| B. | 4.3 mm |
| C. | 5 cm |
| D. | 10 mm |
| Answer» C. 5 cm | |
| 6. |
The minimum thickness of the material to achieve the condition of plane strain is given by ______ |
| A. | B=2.5 (KIC/σo) |
| B. | B=2.5 (KIC/σo)2 |
| C. | B=2.5 (KIC/σo)1/2 |
| D. | B=2.5 (KIC/σo)-1/2 |
| Answer» C. B=2.5 (KIC/σo)1/2 | |
| 7. |
The notch in the thick plate is far more damaging than the groove in a thin plate because of the _________ |
| A. | plane-stress |
| B. | plane-strain |
| C. | triaxle state of stress |
| D. | uniaxial state of stress |
| Answer» C. triaxle state of stress | |
| 8. |
The KIC is independent of heat treatment, texture, melting practice, impurities, and inclusion, etc. |
| A. | True |
| B. | False |
| Answer» C. | |
| 9. |
The value of KIc ____________ with increase in the temperature and __________ with increase in the strain rate. |
| A. | increases, decreases |
| B. | increases, Increases |
| C. | decreases, decreases |
| D. | increases, Increases |
| Answer» B. increases, Increases | |
| 10. |
The stress intensity for a plate is given as K=σ√(πa) tan(πta); where a is crack length equal to 6 mm, t is the thickness of the plate equal to 1 cm, and σ is the nominal stress applied. Determine the maximum allowable stress if KIc=50 MPa m-1/2. |
| A. | tan(πta); where a is crack length equal to 6 mm, t is the thickness of the plate equal to 1 cm, and σ is the nominal stress applied. Determine the maximum allowable stress if KIc=50 MPa m-1/2.a) 100 MPa |
| B. | 145 MPa |
| C. | 200 MPa |
| D. | 500 MPa |
| Answer» C. 200 MPa | |