Patent ID: 7877229

Claim:
A computer program product comprising at least one non-transitory tangible computer-readable storage medium having computer-readable program instructions stored therein that, when executed by a processor, enable a processor-based system to calculate a Load Enhancement Factor, comprising the method steps of: retrieving a data set comprising at least one of coupon level test data and component level test data from at least one database; analyzing the data set for fit with at least one of a Weibull distribution model and a normal distribution model; calculating a stress to life cycle relationship accounting for scatter in the test data by relating the log of a scale parameter of a Weibull distribution function with the log of a stress level of a stress to fatigue life curve; and calculating the Load Enhancement Factor (LEF) based on the stress to life cycle relationship by solving the following equation: LEF( N 0 )= S E /S B ( N 0 ) 1/{circumflex over (θ)} 1 =exp(−{circumflex over (θ)} 0 /{circumflex over (θ)} 1 )/ S B ( X I N 0 /Γ(1+1/{circumflex over (β)} SN )) 1/{circumflex over (θ)} 1 , wherein N o represents a test duration in number of lifetimes, S E represents a stress level computed from an expected value of a fatigue cycle distribution, S B represents a stress level computed from a B-basis value of the fatigue cycle distribution, θ 0 represents an intercept parameter of a Weibull regression model, θ 1 represents a slope parameter of the Weibull regression model, X I represents the number of cycles on the coupon level defining one lifetime, Γ represents a gamma function β SN represents a shape parameter of the Weibull regression model; and adjusting at least one of a load level and a duration of a component-level fatigue test by an amount equivalent to the Load Enhancement Factor.