On the time compression (test acceleration) of broadband random vibration tests

Shires, David

doi:10.1002/pts.915

Cited by 44 publications

(60 citation statements)

References 7 publications

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“…A further question is the required duration of the simulation depending on the transportation distance. This is a very important practical question, becauseespecially in case of large distance transports-simulating the whole length is impossible and the PSD function will not excite real values but it will compress all the unique vibrations in the whole frequency range and the small bandwidth vibrations also [15]. It can be said that with the transforming of vibrations to frequency ranges the possibility of measuring in time range will be lost.…”

Section: Figure 1 Servo-hydraulic Vibration System Figure 2 Electromentioning

confidence: 99%

Consideration on road transport vibration simulation techniques for packaging testing purposes

Pidl

2017

Acta Tech Jaur

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Transportation is essential for many logistics systems and vibration is one of the most critic physical circumstances on road causing numerous possible damage sources. One of the primary sources of these damages is often the broadband random vibration. This effect cannot be handled with formal mechanical models; therefore, vibration test simulation is essential for packaging testing. The current vibration systems use Power Spectral Density (PSD) functions to control the intensity of random signal in laboratory based on Fast Fourier Transformation (FFT). Naturally, the PSD frequency does not contain time series data making it hard to determine how long a given simulation should be performed. In this paper, mathematical and probability methods are presented that can be used for representing real vibration circumstances.

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Section: Figure 1 Servo-hydraulic Vibration System Figure 2 Electromentioning

confidence: 99%

Consideration on road transport vibration simulation techniques for packaging testing purposes

Pidl

2017

Acta Tech Jaur

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“…Accelerated random vibration testTo evaluate the fatigue damage, the tests using the PSD from standards or road vibration data are carried out, which usually costs a long time. It is significant to establish methodology of accelerated random vibration test Response of packageIn previous studies, package was never assumed to separate from base, and response of package was symmetrical.…”

Section: Introductionmentioning

confidence: 99%

“…To evaluate the fatigue damage, the tests using the PSD from standards or road vibration data are carried out, which usually costs a long time. It is significant to establish methodology of accelerated random vibration test …”

Section: Introductionmentioning

confidence: 99%

Influence of jumping phenomenon on response of package under random vibration

Fang

Wang

2018

Packag Technol Sci

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Because asymmetric contact is characteristic of the package surface, jumping phenomenon may happen under strong random vibration. To study the influence of jumping phenomenon on package response, a piecewise linear random vibration model is established. By applying Fokker‐Planck‐Kolmogorov (FPK) equation method, distribution of displacement composed of Gaussian distribution and exponential distribution is obtained. After that, distribution of maxima of displacement composed of Rayleigh distribution and exponential distribution is obtained. The proportion of time taken by loss of contact in a single cycle is studied under different peak of displacements. When the peak of displacement is from 1 to 3, the period is from 2π to 2.56π, and proportion of time taken by loss of contact is from 0% to near 50%. By applying the relation between peak of displacement and contact force, distribution of maxima of contact force can be obtained as translational Rayleigh distribution, which is also proved by numerical simulation and experiment respectively. Moreover, by numerical simulation, distribution of acceleration and time history of modified displacement are obtained. It is found that when Root‐Mean‐Square (RMS) value of displacement signal increases, probability of loss of contact becomes greater, and the time cost by the same number of cycles will be prolonged. By experiment, distribution of acceleration and acceleration Power Spectral Density (PSD) are obtained. It is found that when random excitation increases, the probability of −g increases and the frequency corresponding to peak of acceleration PSD declines. It indicates that the loss of contact causes the decline of the central frequency.

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“…Therefore, G rms ‐ N curve is the foundation of accelerated random vibration test. Shires ever investigated the time compression of the inverse power law and showed the high sensitivity of the power exponent b in accelerated vibration testing. It is noted that the input power spectral density (PSD) shapes featuring the testing environment and the real one must have the same shape in the method of transport packaging accelerated random vibration.…”

Section: Introductionmentioning

confidence: 99%

Investigation on vibration scuffing life curves

Wang

Rouillard

2018

Packag Technol Sci

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The printing images on products and packaging play an important role in increasing the business value, adding artistic quality, and sending information. During transportation, scuffing of the printing images will emerge due to vibrations and impacts induced by rough roads and vehicles. This paper investigates experimentally the vibration scuffing through an ink transfer device. The scuffing value–time curves are obtained. Then the scuffing life curves Grms,e‐Na,e based on excitation acceleration root‐mean‐square (RMS) and Grms,r‐Na,r based on relative acceleration RMS are developed. Both Basquin‐type and exponential‐type curves may be applied to describe the scuffing life in this case. The excitation frequency width covering the resonance frequency has a significant effect on the scuffing life curve Grms,e‐Na,e based on excitation acceleration RMS; however, it is not obvious on the scuffing life curve Grms,r‐Na,r based on relative acceleration RMS. The vibration system filters out the broadband excitation vibration frequencies away from the resonance zone and makes the relative acceleration signal a narrow one. The scuffing life curve in the resonance scuffing state is very different from that in the nonresonance scuffing state, and they should be distinguished in practical application. The scuffing life equations and curves obtained in this paper may provide a reference to the further research on packaging scuffing and its test evaluation and accelerated vibration test in laboratory.

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On the time compression (test acceleration) of broadband random vibration tests

Cited by 44 publications

References 7 publications

Consideration on road transport vibration simulation techniques for packaging testing purposes

Consideration on road transport vibration simulation techniques for packaging testing purposes

Influence of jumping phenomenon on response of package under random vibration

Investigation on vibration scuffing life curves

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