Unformatted text preview: stress free) B. A large ceramic component with E = 300 GPa and K IC = 2.5 MPa m 1/2 is a candidate for an application in which it must be cooled quickly from 900 o C to 25 o C. There is a central crack (through-thickness) of 2a =5 mm in the component (assume Y = 1). Using your knowledge of fracture mechanics and thermal stress, thermal strain and thermal shock, estimate the coefficient of thermal expansion that the ceramic must have to survive this cooling. (Ans . About 0.1x10-6 o C-1 ) Using the Properties Table B.6 (p. A19) in Callister, determine if it is likely that a ceramic with the estimated coefficient of thermal expansion exists? (Ans . Fused silica is the closest but the other commercial ceramics do not qualify) C . Why does the engineering stress-strain curve drop off after the UTS? M. McDill September 2009 AERO3700 - PA3...
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- Spring '11
- mechanics, Thermal Expansion, Coefficient of thermal expansion, Fused quartz