Miles' Equation in Random Vibrations

Wijker, Jaap

doi:10.1007/978-3-319-73114-8

Cited by 8 publications

(6 citation statements)

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“…An acceleration spectral density (ASD) is the mean square acceleration within a continuously distributed frequency band divided by the bandwidth. Based upon Mile's equation for a single degree of freedom system (SDOF), 17 the ASD is estimated as follows:…”

Section: ½Mmentioning

confidence: 99%

“…where W € U ð f Þ is the acceleration spectral density (g 2 /Hz), € x rms is the root mean square acceleration, ζ is the damping ratio = 0.05, 16,17 Q is the amplification or quality factor = 10. The satellite structure is subjected to mechanical random vibrations during launch phase as listed in Table 8.…”

Section: ½Mmentioning

confidence: 99%

“…The equivalence of both random and sinusoidal vibrations is based upon Mile's equation applications for single degree of freedom systems. 16,17 It can be observed that the root mean square acceleration (€ x rms Þ is equated for both random response and sinusoidal response as follows:…”

Section: ½Mmentioning

confidence: 99%

“…In this context, the equivalency of harmonic and random vibrations approach is utilized via Mile's equation. 16,17 Additionally, superposition of the von Mises stresses due to both quasi-static Figure 1. Satellite stowed and in-orbit configurations.…”

Section: Introductionmentioning

confidence: 99%

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Structural optimization of a small earth remote sensing satellite

Aborehab,

Kassem,

Nemnem

et al. 2023

Noise & Vibration Worldwide

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Structural sizing optimization is a crucial step in the process of modern satellite structural design. It warrants minimizing the satellite structural mass while improving the overall quality and reliability of such design. This article discusses thoroughly the structural optimization of a small earth remote sensing satellite whose primary structure is based upon aluminum honeycomb sandwich plates. A novel contribution has been conducted in extending the optimization problem to include the main static and dynamic loads acting simultaneously on the satellite during launch phase utilizing the results of static, buckling, modal, and harmonic response analyses. The small satellite optimization process starts initially with formulating the optimization problem based upon the structural analyses results. Subsequently, miscellaneous optimization techniques utilizing ANSYS workbench capabilities represented in “DesignXplorer” module are employed. Finally, the results are compared with other results obtained from a MATLAB code based upon both genetic and sequential quadratic programming algorithms. The optimization process leads to approximately 30% mass reduction in the proposed satellite structure. A special attention is drawn towards meta-models due to their capabilities in solving complex structural models with a reasonable wall-clock time.

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Section: ½Mmentioning

confidence: 99%

Section: ½Mmentioning

confidence: 99%

Section: ½Mmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Structural optimization of a small earth remote sensing satellite

Aborehab,

Kassem,

Nemnem

et al. 2023

Noise & Vibration Worldwide

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show abstract

“…The relationship between a random input spectrum and the response spectrum of a linear system can also be deduced by the following [9]:…”

Section: Governing Equationsmentioning

confidence: 99%

An FEA Investigation of the Vibration Response of the BEATS Detector Stage

Mokoena,

Bhamjee,

Connell

et al. 2023

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The Synchrotron-light for Experimental Science and Application in the Middle East (SESAME) facility is in the process of designing, procuring, and installing a new beamline for tomography (BEATS). The BEATS experimental hutch, hosting sample and detectors, will be located 43 m away from the undulator in the synchrotron ring. Noise in the form of vibration originating from different sources transferred to the detector stage can be a source of poor image quality thus it is important that the detector stage is analysed for its vibration transmission properties. In this study, the result of a three-dimensional random vibration analysis using Finite Element Analysis (FEA) for the detector stage is presented which leads to an estimate of the severity of the vibrations. The random vibration source is that of the ground which was measured exactly where the detector stage will be mounted. The random vibration analysis is conducted in two stages; the modal frequencies of the structure are calculated, thereafter, the random vibration analysis is conducted and the response power spectrum density (PSD) of the structure is calculated along with the root mean square (RMS) displacement values. Since the beamline BEATS is under installation, an existing structure installed at beamline ID28 of the European Synchrotron Radiation Facility (ESRF) was used to validate the model. The model used on the ID28 structure deviated from the experimental results on modal analysis by 2% - 4% on random vibration analysis. This suggested that the model is valid. The analysis as applied to the BEATS detector stage design predicts that the RMS displacement values are less than the pixel size of the detector which is 1 μm. Thus, the structure is sufficiently engineered to moderate the floor vibrations.

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Rapid Calculation of Safe Acceleration Values for Aircraft Structures Under Flight Test

Dosman

Gorman²

2019

ICAF 2019 – Structural Integrity in the Age of Additive Manufacturing

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Miles' Equation in Random Vibrations

Cited by 8 publications

References 0 publications

Structural optimization of a small earth remote sensing satellite

Structural optimization of a small earth remote sensing satellite

An FEA Investigation of the Vibration Response of the BEATS Detector Stage

Rapid Calculation of Safe Acceleration Values for Aircraft Structures Under Flight Test

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