초록 ▼

A method for determining the resonant frequency of vibration of a rotating blade comprises determining the approximate resonance frequency and rotating a blade at a plurality of frequencies in a range above and below the approximate frequency. At each frequency two measurements are taken representat

A method for determining the resonant frequency of vibration of a rotating blade comprises determining the approximate resonance frequency and rotating a blade at a plurality of frequencies in a range above and below the approximate frequency. At each frequency two measurements are taken representative of synchronous amplitudes at each measurement point (P.sub.1 and P.sub.2) wherein the two points are separated by an angle .beta. and there are an unknown number x of complete synchronous vibrations between the two points. A set of data is provided and a plot of P.sub.1 and P.sub.2 produced, the data being analysed to determine a likely value of x and hence the resonant frequency.

대표청구항 ▼

[ I claim:] [1.] A method for determining a resonant frequency of vibration of a rotating blade, the method comprising the steps of: determining the approximate resonant frequency; rotating the blade at each of a plurality of frequencies in a range from below to above the approximate resonant freque

[ I claim:] [1.] A method for determining a resonant frequency of vibration of a rotating blade, the method comprising the steps of: determining the approximate resonant frequency; rotating the blade at each of a plurality of frequencies in a range from below to above the approximate resonant frequency; and at each frequency:taking a first measurement P.sub.1 representative of synchronous vibrational amplitude at a first point, and taking a second measurement P.sub.2 representative of synchronous vibrational amplitude at a second point wherein the first and second points are separated by an angle .beta. swept by the blade; and wherein there are an unknown quantity x of synchronous vibrations between the first and second points to provide a set of data comprising the plurality of frequencies and for each frequency a measurement P.sub.1 and a measurement P.sub.2, so that a plot of P.sub.1 against P.sub.2 will display that features of the plot depends on x; and from x calculating the resonant frequency of vibration.