Praxis der Schwingungsmessung

Kuttner, Thomas; Rohnen, Armin

doi:10.1007/978-3-658-25048-5

Cited by 10 publications

(2 citation statements)

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“…In addition to the noise, multiples of the rotational frequency are visible in the measurement signal, which overlay the structural response. For this reason, the transfer function H 1 was used for evaluating the measurement data, which is commonly employed in measurement technology when the output measurement quantity is superimposed by noise [35]. H 1 results from the quotient of the cross-power spectrum G XY (jw) and the auto-power spectrum G XX (w) of the input signal [35] (see Equation ( 5)).…”

Section: Rotating Statementioning

confidence: 99%

Vibration Reduction on Circular Disks with Vibroacoustic Metamaterials

Rieß,

Schmidt,

Kaal

et al. 2024

Applied Sciences

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Vibroacoustic metamaterials represent an innovative technology developed for broadband vibration reduction. They consist of an array of local resonators and are able to reduce vibrations over a wide frequency range, commonly referred to as a stop band. Vibroacoustic metamaterials may be a promising strategy to reduce out-of-plane vibrations of thin-walled, disk-shaped structures, such as saw blades. However, their behavior in rotating systems has not yet been fully understood. In this study, a vibroacoustic metamaterial integrated into a circular disk for the reduction of out-of-plane vibrations is experimentally investigated in the rotating and non-rotating state. Derived from the predominant frequency range of noise emitted by saw blades, a vibroacoustic metamaterial with a numerically predicted stop band in the frequency range from 2000 Hz to 3000 Hz, suitable for integration into a circular disk, is designed. The resonators of the metamaterial are realized by cutting slots into the disk using a waterjet cutting machine. To experimentally examine the structural dynamic behavior, the disk is excited by an impulse hammer and observed by a stationary optical velocity sensor on a rotor dynamics test stand. The results of the rotating and the non-rotating state are compared. The measurements are carried out at two different radii and at speeds up to 3000 rpm. A distinct stop band characteristic is shown in the desired frequency range from 2000 Hz to 3000 Hz in the rotating and non-rotating state. No significant shift of the stop band frequency range was observed during rotation. However, adjacent modes were observed to propagate into the stop band frequency range. This work contributes to a better understanding of the behavior of vibroacoustic metamaterials in the rotating state and enables future applications of vibroacoustic metamaterials for vibration reduction in rotating, disk-shaped structures such as saw blades, brake disks or gears.

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Section: Rotating Statementioning

confidence: 99%

Vibration Reduction on Circular Disks with Vibroacoustic Metamaterials

Rieß,

Schmidt,

Kaal

et al. 2024

Applied Sciences

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“…1,2 The performance of a sealing system, comprising a gearbox, rotary shaft seals and a driveshaft is significantly influenced by several internal and external factors during various vehicle manoeuvres. 3 These influential factors/conditions are shown in Figure 1. Among them surface quality of the seal, 4 design of the radial shaft seal and the operating behaviour of the transmission fluid are the most prominent.…”

Section: Introductionmentioning

confidence: 99%

An investigation of oil leakage from automotive driveshaft radial lip seals

Nomikos

Rahmani

Morris

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part D:

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There is an ever-increasing stringent directive for environmental protection, even for the previously rather negligible lubricant leakage from vehicular drivetrains. Leakage from transmissions and differential units are no longer permitted and can lead to excessive warranty costs. Additionally, the trend in component downsizing, including for sealing systems has indirectly altered the leakage behaviour of transmissions. To guarantee leakage-free operation, it is important to establish standardised methods of manufacturing processes, particularly for surface topography of shafts. The paper investigates the leakage from two different shaft machining processes: corundum and cubic boron nitride (CBN) grinding. The performance of passenger car transmission sealing system is ascertained with the development and use of a novel detailed representative fully instrumented test rig. A test protocol is set up to assess the performance of shafts during break-in period and correlate shaft topographic data with its measured performance. The results show that the measured oil leakage correlates well with the shaft surface skewness whilst no particular trend is observed with Ra, Rz and shaft lead angle values, which form the basis of most current standards used in industry. Overall, it was observed that shafts with negative skewness in their roughness profile produced lesser leakage. A basic analytical predictive method is also developed which corroborates with the measured data.

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