Materials Assignement 5 Attempt 2

# Materials Assignement 5 Attempt 2 - WebCT Quiz Homepage

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WebCT Quiz Homepage http://webct.mcmaster.ca/SCRIPT/MATLS_1M03_T2_06_newRestore/s. .. 1 of 4 24/03/2006 1:03 PM View Results Name: BRYCE JONES Attempt: 2 / 3 Out of: 9 Started: March 21, 2006 11:23pm Finished: March 24, 2006 1:02pm Time spent: 61 hr, 38 min., 42 sec. Question 1 (1 point) True or False? A brittle material typically exhibits substantial plastic deformation with high energy absorption before fracture. Student response: Correct Response Student Response Answer Choices a. True b. False General feedback: False . A brittle material exhibits little or no plastic deformation with low energy absorption before fracture. For more information, see the section on Fundamentals of Fracture in the text. Score: 1 / 1 Question 2 (1 point) A structural component is fabricated from an alloy that has a plane strain fracture toughness of 31.3 MPa-m 1/2 . It has been determined that this component fails at a stress of 173 MPa when the maximum length of a surface crack is 1.83 mm. What is the maximum allowable surface crack length without fracture for this same component that is made from another alloy that has a plane strain fracture toughness of 51.1 MPa-m 1/2 ? The components will all be subject to the same amount of stress while in use. Use decimal notation, digits after decimal: 2 Student response: 4.88 mm Correct answer: 4.88 mm General feedback: Recall that Y is dependent on specimen sizes and geometries, so for a structural component this would be constant, even if it was made out of a different material. The components will all experience the same amount of stress while in use, so the applied stress will not exceed 173 MPa in the second alloy. Use equation 8.5 to solve for Y, and then equation 8.7 to find the maximum allowable crack length in the second component.

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## This note was uploaded on 02/08/2010 for the course MATLS 1M03 taught by Professor Okon during the Winter '09 term at McMaster University.

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Materials Assignement 5 Attempt 2 - WebCT Quiz Homepage

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