Measurement and analysis of vibration levels for express logistics transportation in South China

This paper reviews the various ways that have been proposed to characterise road transport vehicle vibrations and recommends a new approach to characterise the vibrations levels during a transport journey. Some 47 road vehicle vibration records, obtained from a broad range of conditions, were analysed, and results show that the root-mean-square (rms) distribution of the vibrations can be accurately modelled with a reduced version of the three-parameter Weibull distribution (shape parameter set to 2). This statistical approach to characterising road vehicle vibrations takes into account the random fluctuations in rms levels that occur naturally during a road journey and can be used to classify the severity of RVV. This offers significant improvement on the simplistic mean rms value that has, so far, been the sole parameter to describe vibration levels during transport. The Weibull location parameter represents the low threshold of the rms level in the record (except when xo is less than zero, in which case the low rms threshold is zero), whereas the Weibull range parameter is proportional to the range of rms level. Results also reveal a strong relationship between the rms mean and the sum of the location and scale parameters. In addition, this enables generation of rms distributions from the mean power density spectrum (PDS) alone. The modified (fixed-shape) Weibull distribution can be used to faithfully describe the entire statistical distribution of the rms level of a journey or transport mode with just two parameters. This new approach can be used in a practical way for quantifying and comparing transport vibration rms levels for design and testing purposes.

Section: Introductionmentioning

confidence: 52%

Using the Weibull distribution to characterise road transport vibration levels

Rouillard

Lamb

2020

“…And the simulation effect has been compared from the following aspects, including statistical parameters, vibration intensity, acceleration probability distribution, moving RMS probability distribution, and PSD plots. As previous study, 15 Prior to shipment, the data recorder was configured with the following settings.…”

Section: Simulation Methods Chosen For Comparisonmentioning

confidence: 99%

“…As previous study, data recorder (SAVER 3X90, Lansmont Corporation, Monterey, CA, USA), with built‐in triaxial acceleration sensors, was used to record vibration signals in lateral, longitudinal, and vertical directions. The instrument was directly centred in the cargo space or on the beam, with 3M double‐faced adhesive tape (3M, Minnesota Mining and Manufacturing Corporation, Sao Paulo, MN, USA).…”

Section: Data Measurementsmentioning

confidence: 99%

Comparison study on simulation effect of improved simulation methods for packaging random vibration test

Zhou

Wang

2018

Self Cite

In general, existing testing methods for packaging design employ Gaussian distributions to represent vibration induced by road profiles. However, the actual road vehicle vibration is non‐Gaussian. The key limitation is that the simulated Gaussian vibration cannot reconstruct the shock events buried in the vibration, which will result in inaccurate reliability evaluation of cushion packaging. A new simulation technique called shock extraction has been proposed and validated in our earlier study. This article is a further study of our previous research. The shock extraction method has been compared with other three representative simulation methods including the single‐level PSD, three‐way split spectral, and wavelet decomposition in terms of simulation effect. Signal simulated by the shock extraction method possesses the same vibration intensity, duration, approximate statistical characteristics, and PSD plots with the original signal. The results show that the simulation effect of the shock extraction method is the best, and the worst is the single‐level PSD. The wavelet decomposition and three‐way split spectral are somewhere in the middle.

“…The unit of PD is G 2 /Hz, and the calculated data are presented from 1 to 200 Hz in this study. Here, it has to be noted that the noise floor of the SAVER 3X90 is around 0.02 G RMS at a 500‐Hz bandwidth, so the events below this limit were filtered out from the analysis, as previous research has already done . This is in addition to those events that happened during the handlings or transshipments to obtain pure vibration events.…”

Section: Design Of Experimentsmentioning

confidence: 99%

“…Here, it has to be noted that the noise floor of the SAVER 3X90 is around 0.02 G RMS at a 500-Hz bandwidth, so the events below this limit were filtered out from the analysis, as previous research has already done. [9][10][11][12][13] This is in addition to those events that happened during the handlings or transshipments to obtain pure vibration events. Furthermore, the probability density function (PDF) of G RMS was also developed to present the kurtosis (K) and skewness (S) along the statistical data of each transportation stage.…”

Section: Data Analysesmentioning

confidence: 99%

Vibration and acceleration levels of multimodal container shipping physical environment

Böröcz

2019

In global supply chains, multimodal transportation plays a dominant role in worldwide shipping. The rail, truck, and vessel combination is the most commonly used mode for non‐time sensitive shipments between continents. This study focused on measuring the transportation environment effects (vibration and acceleration levels) in 40‐foot ISO container shipments using multiple modes of transport, originating in Hungary and destined for Mexico, India, and China over several weeks. The study also measured multimodal shipping routes without vessel transportation to China over Trans‐Siberian and Trans‐Manchurian railway lines. The transshipments and handling events in container hubs and terminals were separately analyzed. The results show the comparison of vibration intensity (in PSD) of different route conditions between various continents, and the possibility of acceleration levels during transshipments and handling events. The measured data show that extreme acceleration levels in vertical direction (9.37 G) occur while containers are handled in a seaport, and in lateral (4.45 G) and longitudinal (5.55 G) directions while they are transshipped by truck to rail container terminals. The rail vibration levels in Russia and China showed a lower intensity in the frequency range of 1 to 15 Hz, and higher between 15 and 200 Hz than in Europe; the lowest vibration levels occurred when the containers traveled on the sea, and truck vibration levels were very similar to previous research and ISTA protocols.