Question An aircraft component is subjected to a spectrum of cyclic loads during a single flight, as shown in the table below. Your task is to estimate the safe life for the component (in flights) using Miner's Theorem. All stresses shown are MPa. Load Component max Omin Cycles/flight (n) Pressurisation 170.0 0.0 1 Turns 130.0 65.0 25 Gusts 50.0 -50.0 150 Strong Turbulence 120.0-120.0 40 The aircraft material has been characterised extensively under fatigue loads. For the spectrum of loads experienced by the aircraft, the S-N curve can be estimated using the following function: Omax = 1600 (N-0.16) (1.5R) where: N is the number of cycles R is the stress ratio This can be expressed in terms of cycles as: N = [(0.000625) max (1.5-R)] -6.2 N = [(0.000625) max (1.5-R)] -6.25 Part a Complete the following table to calculate the life fractions for each load component. Load Component max min n Life N Life Fraction n/N Pressurisation Turns Gusts R 170.0 0.0 1 130.0 65.0 25 50.0-50.0 150 Strong Turbulence 120.0-120.0 40 Notes: Answer in integer, decimal or E notation (1.0E-6) Errors will carry across a row. If you get one of the values incorrect your next answer in the row won't be penalised as a result. If you can't calculate a value, make a reasonable guess at it and keep going because the following values will carry through your guess in the calculations. Part b Estimate the expected life of the component (in flights): flights Assuming a scatter factor of 3, estimate the safe life of the aircraft (in flights): flights