AE07.pdf

Emission test transducers are located on each ram

This preview shows page 42 - 44 out of 47 pages.

emission test transducers are located on each ram, each connected into one acoustic emission preamplifier. Only one preamplifier is required because only one ram is active at a time during straightening. The amplified signal is fed into the acoustic emission test system for processing. The system consists of (1) a circuit to filter unwanted high and low 263 Acoustic Emission Testing for Process and Condition Monitoring P ART 6. Crack Detection during Straightening of Axles and Shafts F IGURE 40. Block diagram of an acoustic emission system for shaft straightening. Preamplifier Transducers Acoustic emission in Transducer coupling test Alarm out Straightening process Acoustic emission system Transducer coupling test Alarm light Audible alarm Crack alarm out Crack alarm Straightening Axle position Shaft straightening programmable controller Axle holder Anvil Axle Axle holder
Image of page 42

Subscribe to view the full document.

frequency noises, (2) signal processing circuitry to extract acoustic emission time and hit based features and (3) an onboard computer to process the acoustic emission test signals and to separate noise from crack signals with a pattern matching algorithm for intelligent crack detection. The acoustic emission test system is fully coordinated by the shaft straightening controller through input and output signals between the systems. There are two main acoustic emission test processes being coordinated by the shaft straightening controller: a transducer coupling test and a straightening process. Each process is described below. Transducer Coupling Test The transducer coupling test is carried out just before the shaft is straightened. Once a shaft (or axle) is inserted into the straightening fixture, the machine sets up for the straightening process by rotating the axle into position and advancing the ram into place over the shaft to be straightened. When the ram is touching the axle with a slight force, the controller signals to the acoustic emission test system that a transducer coupling test should be carried out. The acoustic emission test system excites the pulser transducer, sending simulated acoustic emission test signals down the shaft. The signals are detected by the ram transducer in contact with the axle and the system alerts the shaft straightening controller that the simulated crack has been detected. This diagnostic step ensures that the entire acoustic emission system is operating properly before beginning a straightening operation. Straightening Process Once the transducer coupling test is successful, the shaft straightening controller turns off the transducer coupling test signal and starts the straightening process, which indicates to the system that a test has started. At this point, the system is processing all acoustic emission activity to detect a crack. The acoustic emission test system contains a crack detection algorithm to distinguish cracking from noises generated by the machine, environment or process. This algorithm eliminates false alarms that reject good product.
Image of page 43
Image of page 44

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern