text: To help explain the Resonant Acoustic Method (NDT-RAM), let’s consider how a person can determine between a good bell and a cracked bell .
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  The impact “rings” the bell and produces sound. Ears pick up the sound and transform it to an electrical signal. The brain processes the signal into tones or notes, also known as frequencies. A comparison is made to bells heard before to determine “pass” or “fail.”
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  An industrial impactor taps each part with a measured and repeatable force, producing sound. A microphone is used to transform the parts' response into electrical signals for analysis. The smart digital controller uses a Fast Fourier Transform (FFT) method to determine frequency characteristics. NDT-RAM software compares the results to criteria limits and accepts or rejects the part accordingly.
  Impact the Part
  The part can either be impacted with a manual hammer or an industrial electric hammer. It is important to excite the part with a proper, repeatable force. This will improve the repeatability and reliability of the test.
  Measure the Response
  A microphone is used to provide accurate acoustic measurement of the component's resonant frequency and amplitude values. The NDT microphone provides a perfect fit of price, accuracy and dependability.
  Process the Data and Quantify the Results
  Changes in mass, stiffness and damping due to certain defects can cause...
  resonant frequency peaks to shift in both frequency and amplitude.
  resonant frequency peaks to shift frequency but maintain amplitude.
  peak shifts with more pronounced splits in resonant frequency.
  resonant frequency peak energy to disappear completely.
  The family of NDT-RAM systems range from a portable manual system ideal for parts investigation and troubleshooting, to a semi-automated system for easy integration into your existing process, to a fully automated conveyor-based or drop test fixture system as a turn-key solution for 100% parts inspection.
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  About The Modal Shop
  The Modal Shop, Inc. offers structural vibration and acoustic sensing systems and services for various applications in design and test laboratories as well as manufacturing plants. An extensive sound and vibration rental program, precision calibration systems, and both modal and vibration shakers are designed to simplify test phases. Non Destructive Testing Systems help manufacturers provide 100% quality inspection of metal components. The Modal Shop is a wholly owned subsidiary of PCB Piezotronics, Inc., a wholly owned subsidiary of Amphenol Corporation.
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  +1 513.351.9919
  10310 Aerohub Boulevard
  Cincinnati, OH 45215 USA
  SensorlineSM
  716.684.0001
  info@modalshop.com
  +1 513.351.9919
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  © 2021 PCB Piezotronics, Inc. In the interest of constant product improvement, specifications are subject to change without notice. PCB®, ICP®, Swiveler®, Modally Tuned®, and IMI® with associated logo, Spark®, Blaze®, SoundTrack LxT®, SoundExpert LxT®, and Digiducer® are registered trademarks of PCB Piezotronics, Inc. in the United States. ICP® is a registered trademark of PCB Piezotronics Europe GmbH in Germany and other countries. SensorLineSM is a service mark of PCB Piezotronics, Inc.