In Problem 15.14, it was assumed that a thickness B = 60 mm was sufficient to guarantee pl...

In Problem 15.14, it was assumed that a thickness B = 60 mm was sufficient to guarantee plane strain fracture of the titanium alloy.

a. The 0.2% yield stress of this alloy is 850 MPa in a uniaxial tensile test. Is the thickness B sufficient to guarantee plane strain fracture?

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b. Determine the minimum yield stress of an alloy of the same toughness KIC that would give a valid KIC for this size of specimen.

Problem 15.14

A single edge-cracked bend specimen (Figure 15.2a) is made of a high-strength titanium alloy with fracture toughness . It has thickness B = 60 mm, a depth W = 120 mm, and a length L = 480 mm. An edge crack of length a = 60 mm is cut into its lower edge. Determine the load P that produces fracture. Assume that Case 6 of Table 15.2 applies with M = PW.

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

TABLE 15.2 Stress Intensity Factors KI