Acoustic inspection of one-piece bladed wheels
First Claim
1. / A method of acoustically inspecting a one-piece bladed wheel, the method comprising the following steps:
- a) driving the wheel in rotation;
b) subjecting a first blade to mechanical excitation;
c) picking up an acoustic response and generating a corresponding electrical signal;
d) performing an FFT computation to determine the frequency response of said first blade of the wheel;
e) storing the electrical signal and the associated frequency response;
f) repeating steps b) to e) for each blade of the wheel;
g) identifying characteristic frequencies of each blade of the wheel from the stored frequency responses; and
h) rejecting or accepting a wheel depending on whether the resulting frequency distribution matches a predetermined set of forbidden frequency distributions.
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Accused Products
Abstract
These objects are achieved by a method of acoustically inspecting a one-piece bladed wheel in which the wheel is driven in rotation; each blade of the wheel is subjected to mechanical excitation; its acoustic response is picked up and a corresponding electrical signal is generated; its frequency response is determined by computing a FFT; the electrical signal and the associated frequency response are stored; the characteristic frequencies of each blade of the wheel are identified; and a wheel is rejected or accepted depending on whether or not the frequency distribution obtained in this way matches a predetermined set of forbidden frequency distributions. Advantageously, an additional step is provided in which the defects of a blade are determined by comparing its frequency response with predetermined frequency responses that are characteristic of various types of defect.
16 Citations
7 Claims
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1. / A method of acoustically inspecting a one-piece bladed wheel, the method comprising the following steps:
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a) driving the wheel in rotation;
b) subjecting a first blade to mechanical excitation;
c) picking up an acoustic response and generating a corresponding electrical signal;
d) performing an FFT computation to determine the frequency response of said first blade of the wheel;
e) storing the electrical signal and the associated frequency response;
f) repeating steps b) to e) for each blade of the wheel;
g) identifying characteristic frequencies of each blade of the wheel from the stored frequency responses; and
h) rejecting or accepting a wheel depending on whether the resulting frequency distribution matches a predetermined set of forbidden frequency distributions. - View Dependent Claims (2, 3, 4)
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5. / Apparatus for acoustically inspecting a one-piece bladed wheel, the apparatus comprising:
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a) drive means for rotating said wheel;
b) mechanical excitation means for subjecting each of the blades of the wheel to mechanical excitation;
c) acoustic receiver means for picking up an acoustic response and for generating a corresponding electrical signal;
d) computation means for computing the frequency responses of each blade of the wheel by means of an FFT;
e) storage means for storing the electrical signals and the associated frequency responses;
f) identification means for identifying characteristic frequencies of each blade of the wheel on the basis of their stored frequency responses; and
g) classifier means for rejecting or accepting a wheel depending on whether or not the resulting frequency distribution matches a predetermined set of forbidden frequency distributions. - View Dependent Claims (6, 7)
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Specification