High-Frequency Impulse Response Testing of Lightly-Damped Turbine Disks

For the multi-time scale characteristics of vibration signal, a composite multi-frequency dictionary combining the low-frequency Fourier dictionary and the high-frequency impulse time-frequency dictionary is constituted, to decompose multi-component vibration signal into the combination of several one-component signals. The use of empirical model decomposition (EDM) in high-frequency impulse Component signal including feature information is to realize segmented Hilbert-Huang transform of signal and to acquire the time-frequency representation of every one-component signal, which is the process of fault information extraction of vibration signal. The application of the method in main reducer fault diagnosis verifies the engineering practicability and validity of the new algorithm.

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In Situ Acoustic Monitoring of Thermal Spray Process Using High-Frequency Impulse Measurements

Journal of Thermal Spray Technology ◽

10.1007/s11666-017-0673-z ◽

2017 ◽

Vol 27 (1-2) ◽

pp. 50-58 ◽

Cited By ~ 5

Author(s):

Wolfgang Tillmann ◽

Frank Walther ◽

Weifeng Luo ◽

Matthias Haack ◽

Jens Nellesen ◽

...

Keyword(s):

Thermal Spray ◽

High Frequency ◽

Acoustic Monitoring ◽

Thermal Spray Process ◽

Spray Process ◽

Frequency Impulse

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The Transient Response of Structures Using Asymptotic Modal Analysis

Journal of Applied Mechanics ◽

10.1115/1.2789034 ◽

1998 ◽

Vol 65 (1) ◽

pp. 258-265 ◽

Cited By ~ 3

Author(s):

R. R. Reynolds ◽

E. H. Dowell

Keyword(s):

Numerical Methods ◽

Finite Elements ◽

Modal Analysis ◽

Impulse Response ◽

Transient Response ◽

High Frequency ◽

Natural Frequencies ◽

Mode Shapes ◽

Frequency Range ◽

Modal Solution

The transient response of a structure is predicted using an asymptotic modal approximation of the classical modal solution. The method is aimed at estimating the impulse response problem for high frequency regimes where typical numerical methods (e.g., finite elements) are impractical. As an example, the response of a thin elastic panel is modeled in a frequency range that includes a sufficient number of modes. Both impulsive and arbitrary forms of excitation are considered. It is shown that the asymptotic modal analysis yields an excellent estimate of both the local displacement near the excitation location and of the spatially averaged transient response of the panel for moderate time spans after the excitation is applied. Furthermore, as this approach does not require that the mode shapes or natural frequencies of the structure to be calculated, it is an extremely efficient technique.

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A Data Dependent Systems Strategy of On-Line Tool Wear Sensing

Journal of Engineering for Industry ◽

10.1115/1.3185822 ◽

1982 ◽

Vol 104 (3) ◽

pp. 217-223 ◽

Cited By ~ 48

Author(s):

S. M. Pandit ◽

S. Kashou

Keyword(s):

Tool Wear ◽

Natural Frequency ◽

Impulse Response ◽

Indirect Method ◽

Block Diagram ◽

Cutting Conditions ◽

Safe Distance ◽

On Line ◽

Response Testing ◽

Acceleration Component

An indirect method of tool wear sensing and critical wear detection is suggested. It is based on the Data Dependent Systems (DDS) modeling of vibrations from an accelerometer mounted on the tool holder at a safe distance away from the cutting process. The DDS provides an estimate of the tool acceleration component, sensitive to wear alone, at the natural frequency of the tool confirmed by impulse response testing. This acceleration decreases at the beginning, approaches a minimum at the critical wear, and increases again, much the same way as a rate of wear curve. The trend remains unchanged under different cutting conditions, although the actual values change. Based on this finding, an on-line tool wear sensing strategy is proposed, verified by a confirmation experiment and supplemented by a block diagram of microprocessor implementation.

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