Powertrain
Impact offers its customers the GPSys™ software package for stress and fracture analysis of spiral bevel gears. Spiral bevel gears are used in drive trains and their fracture resistance is key to reliability. This package works with the ANSYS® finite element program and the T-900 program from Gleason Works. GPSys provides the user with an assessment of the stress and crack growth rates for a crack through a spiral bevel gear tooth as a function of an operational profile.
ImpactEnergy™ - Bearing Fault Detection Module
The ImpactEnergy™ algorithm is a customizable, Commercial Off-The-Shelf (COTS) sensor compatible, feature extraction technique developed by Impact Technologies that incorporates both high frequency resonance and mid-frequency selected band-pass demodulation. ImpactEnergy takes advantage of a variation of the demodulation process associated with the High Frequency Resonance (HFR) techniques to discover mechanical fault frequencies that serve as early warning indicators for impending failure.
GearMod™ - Gear Fault Detection Module
As previously mentioned, gear failure is another prevalent failure mechanism that occurs in gas turbine engines. Unfortunately, the envelope-based signal processing methods that are used for detecting bearing faults are not the best choice for detecting incipient faults in gears. One of the key differences between the bearing and gear fault detection algorithms is the fact that gear fault detection is best performed when utilizing time synchronous
averaging (TSA).
Impact’s parameterized process accepts various inputs regarding data collection, mechanical system configuration and processing options to compute a time synchronous average in order to extract a residual signal from the TSA. The process diagram describes a “no-tach” algorithm that utilizes an expected range of shaft speed and searches for the actual speed. Note that the first step of the process subdivides the time sample into segments. Blocked processing permits the algorithm to account for shaft non-stationarity, since torsional modulation of speed often occurs. Shaft non-stationarity, if unaccounted for, can often lead to smearing or bleeding of energy across the frequency bins, which reduces the effectiveness of the notch filtering later used to arrive at the residual signal. A linear interpolation is utilized in the frequency domain to further reduce the loss of relevant signal due to frequency smearing and bleed.
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