8.2 estimate the theoretical fracture strength of a brittle material if it is known that fracture occurs by the propagation of an elliptically shaped surface crack of length 0.25 mm (0.01 in.) and having a tip radius of curvature of 1.2 × 10−3 mm (4.7 × 10−5 in.) when a stress of 1200 mpa (174,000 psi) is applied.

34.64Gpa

Explanation:

We can calculate the theoretical fracture strenght by,

Here we have,

Applied stress

Tip radius

lenght of surface crack or half of the lenght of internal crack

Replacing,

Therefore the maximum stress at the crack tip is 34.64Gpa

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a cold ice-tea.

pour in room temperature or cold water. cover the pitcher and refrigerate. steep white or green tea for 6 to 8 hours; steep black or oolong tea for 8 to 12 hours.jun 28, 2015