| 摘要 |
A fabrication of a shim for insertion within a gap extending in two orthogonal directions between two structural members in the building of a mechanical structure is accomplished by measuring the gap to provide a map of gap width. Variations in gap width appear in the map so as to enable machining of the shim with corresponding variations in thickness so as to fit accurately in the gap. Measurement of the gap width is attained by use of two acousto-electric transducer assemblies, each of which is constructed as an array of electrode discs produced by photolithography upon a flexible, electrically-insulating film of piezoelectric material which serves as a substrate for support of electrodes on a front surface thereof and a ground plane structure on a back surface thereof. The two transducer assemblies are secured adhesively to corresponding surfaces of structural members defining the gap, and an acoustically-transmissive gel is disposed between the two transducer assemblies. Electrical ranging circuitry is connected to the electrodes of the transducer assemblies to provide a transmitting array for generating sonic signals and a receiving array for receiving the acoustic signals produced by the corresponding transmitting electrodes disposed across the gap from the receiving electrodes. The time of flight of acoustic signals across the gap serves as a measure of the gap width for preparation of a map of the gap width to serve as a basis for construction of the shim.
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