Many degradation curves illustrate a two-stage property where the deterioration is fast in the first stage and then becomes slow in the second stage. For this sort of degradation curves subject to power function

a rapid determination method was proposed

which can fit and extrapolate the complete degradation curve with the test data from fast degradation stage

or adding a small amount of test data from slow degradation stage. Abundant analyses of real applications and Monte Carlo simulations showed that

under this circumstance the obtained curve can also approach the true value

or be more conservative

which is safe and useable in engineering. Rapid determination methods for three-parameter power function degradation curve (rubber aging curve

S -N curve

ε -N curve

light intensity degrading curve of LED

etc) and four-parameter power function degradation curve (stress relaxation curve

creep rupture curve

and so forth) were discussed

corresponding median degradation curve and confidence limit curve with high confidence level and high reliability were further derived. According to the comparative analyses of two real applications

it can be concluded that the proposed method can save about two-third of test time and cost.