An aircraft engine has turbine blades made of alloy A-286 (see properties below). One critical row...

Transcribed Image Text:

An aircraft engine has turbine blades made of alloy A-286 (see properties below). One critical row of blades has the operating stress of o = 170 MPa (bending plus axial) and temperature T = 650 °C. These values correspond to the most severe operating conditions the aircraft will normally encounter. (a) Determine the number of flight hours after which the blades should be replaced as a part of the maintenance schedule with the safety factor of SF, = 4. (b) Using the service life found in (a), evaluate the temperature margin Tmax - T (°C). Constants for the Larson-Miller Parameter Polynomial Fit (units of hours, K, and MPa) Range of L-M Fit Material log (hours) bọ bị bz O, MPa T, K A-286 (Fe-Ni-Cr alloy) 20 116,400 -120,500 53,460 -8,188 69-758 811-1089 An aircraft engine has turbine blades made of alloy A-286 (see properties below). One critical row of blades has the operating stress of o = 170 MPa (bending plus axial) and temperature T = 650 °C. These values correspond to the most severe operating conditions the aircraft will normally encounter. (a) Determine the number of flight hours after which the blades should be replaced as a part of the maintenance schedule with the safety factor of SF, = 4. (b) Using the service life found in (a), evaluate the temperature margin Tmax - T (°C). Constants for the Larson-Miller Parameter Polynomial Fit (units of hours, K, and MPa) Range of L-M Fit Material log (hours) bọ bị bz O, MPa T, K A-286 (Fe-Ni-Cr alloy) 20 116,400 -120,500 53,460 -8,188 69-758 811-1089