Enveloping and PeakVue - Dissertation Example

Machinery parts composed of bearings are primarily aimed at minimising friction and abrasion. However, due to various reasons like general wear and tear, heating, cracking, rapid temperature change, etc., a bearing may malfunction. This malfunctioning generates repeated discrepancies and mechanistic disruptions, which might be endured by the machinery in the early stages. The problems due to increased frictions inside the bearing parts are usually acoustic in nature, and impact-echo method of vibration monitoring becomes important in detecting them (Sandalone and Street, 1998).

If defects of this category are not diagnosed timely, major functional disruptions or failures may take place. Hence, in the realm of rotating machinery fault analysis, and particularly the bearing fault analysis techniques, fast and sophisticated methods need to be found out and adopted. PeakVue is such a technology which is effectively deployable in mechanical engineering processes like antifriction bearing fault detection (Emerson Process Management, 2011). It effectively helps in diagnosis and severity evaluation of faults in the rotating machines by assessing the peak values of acoustic emission frequency distributions.

Working Almost every metal has comparable fatigue failure curve. The cyclic stress is plotted along the vertical axis and the quantity of cycles to a failure is plotted along the horizontal axis. Metals generally can never reach such a degree of stability that eventual failure of a metallic part (e.g., a bearing) will not take place even if cyclic stress is considerably reduced. The failure will come about some microscopic abrasion, crack or defect in the crystalline structure of the metal solid state.

The actual failure can take place on the metallic surface (visible) or in the metallic lattice below the surface (invisible). The crack eventually grows to an extent that a piece of the bearing element separates out as a spall from the parent metal. (Druiff, 2008) In order to detect the severity of the stress cycles leading to metallic fault and failure, PeakVue deploys a two stage processing. According to Druiff (2008), since the duration of the impulses are very short the analyzer software is programmed such that the sampling is executed very rapidly.

This ensures that the highest possible number of individual wave peaks can be captured. All the values thus obtained are examined and sequenced to diagnose the highest peak present in each specified time interval block. Further, “Since they are not coherent there is no advantage to maintaining the positive and negative peaks as such. The second step is to full wave rectify the chosen peaks to make them unipolar.” (Druiff 2008, pp. 24-25) Finally, the values obtained are stored as samples of waveforms and Fast Fourier Transform (FFT) (Brigham, 2002) is performed subsequently.

PeakVue is a technology that is chiefly pioneered by the renowned Emerson Process Ma