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ENGINEERING, CS 2017 HSC 14 MC

A highly stressed steel plate develops a fatigue crack while in service.
 

Which of the following is the most effective temporary method to slow or stop the crack's growth?

  1. Weld the crack as it is
  2. Drill a hole ahead of the tip of the crack
  3. Drill a hole through the start of the crack
  4. Weld a small steel plate over the tip of the crack
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`B`

Show Worked Solution
  • A and D are possible permanent solutions, but as the question requests the most effective temporary method it must be B or C.
  • Drilling a hole at the tip of the crack is a more effective solution as it prevents the crack from penetrating further, while drilling a hole at the start would not prevent the cracks growth.

`=>B`

ENGINEERING, CS 2022 HSC 6 MC

The diagram shows a steel plate with a crack developing.
 

Which of the following would best prevent the crack from growing?

  1. Welding the crack
  2. Riveting a plate over the crack
  3. Drilling a hole at the end of the crack
  4. Filling the crack with an industrial adhesive
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`C`

Show Worked Solution
  • Drilling a stop hole at the end of a crack can be effective in arresting crack growth as it reduces stress concentration at the crack tip.

`=>C`

Mean mark 59%.