In a plane strain compact specimen test (Figure 15.2), a value of fracture toughness  is e...

In a plane strain compact specimen test (Figure 15.2), a value of fracture toughness  is estimated. The yield strength of the material is Y = 689 MPa, and the specimen thickness is 12.7 mm.

a. Is the value  a valid value for KIC?

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b. What is the maximum value of fracture toughness that can be measured with this specimen?

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c. If the fracture toughness determined in the test is not valid, estimate the plane strain fracture toughness with an accuracy of 6% or less.

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d. What is the required thickness of the specimen to measure plane strain fracture toughness for all conditions?

FIGURE 15.2 Standard toughness specimens. (a) Single edge-cracked bend specimen. (b) Compact tension specimen.