Averaged vibration levels during courier parcel delivery service in small truck in Hungary

Böröcz, Péter

doi:10.5937/fmet1802211b

Cited by 9 publications

(7 citation statements)

References 16 publications

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“…The increasing tendency for kurtosis value upward in the stacked unit can be seen in Figure 10. These phenomena are in line with the previous papers' results in which the non-Gaussian nature of random vibrations on delivery vehicles were investigated [18][19][20][21]. The skewness values in each case were positive and between the values of 1.62-2.63.…”

Section: Statistical Characteristics Of Acceleration Peaks and Rms(g)supporting

confidence: 91%

Experimental Comparison of Field and Accelerated Random Vertical Vibration Levels of Stacked Packages for Small Parcel Delivery Shipments

Molnár

Böröcz

2021

Applied Sciences

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In the last decade, there has been a significant increase in parcel delivery shipments all over the world due to online stores and consumer demand to receive the products in a shorter period of time. It is especially true when situations like COVID-19 limits personal purchases in shopping malls as well as grocery and pharmaceutical stores. This often means that courier operators try to deliver packages utilizing vehicles with racks or shelves, which during the COVID-19 epidemic are not there anymore. This study measured the vertical vibration levels that occur in stacked parcels during express delivery versus the simulation technique in the laboratory. The goal of this paper was to measure and compare the vibration levels between laboratory practice and field transportation. For the measurement a three-layer stacked unit was built to observe the vibration levels on different road conditions in a parcel delivery vehicle and ASTM vibration profile (ASTM International). Then the measured acceleration-time data were analyzed in terms of power spectral densities (PSD) and the presented statistical data provided an understanding of the variability of intensity in different levels in stacked unit. The results showed that the vibration level increases in the stacked load upwards and with worse road conditions, but even in the worst case it did not reach those vibration levels that the laboratory test showed. Moreover, the layers of the stacked unit are in out-of-phase motion in the field, while the stacked unit in the vibration simulation usually is in-phase motion. Results indicate that the proposed vibration simulation does not correlate well with typical field vibration. This is fundamentally true as during a forced vibration created by a single-axis shaker, do not account for additional inputs occurring simultaneously creating an off-balance to the loads and as a result are less severe than simulated conditions. These findings are limited to single axis vibration simulation and unsecured loads.

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Section: Statistical Characteristics Of Acceleration Peaks and Rms(g)supporting

confidence: 91%

Experimental Comparison of Field and Accelerated Random Vertical Vibration Levels of Stacked Packages for Small Parcel Delivery Shipments

Molnár

Böröcz

2021

Applied Sciences

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“…In the case of vibration analysis, power density (PD) levels were determined first as a function of frequency based on the recorded random vibration acceleration levels as used by former researches [9] [10] [11]. The average power density within a narrow band of frequencies (BW) of a given spectrum can be determined by G rms values based on the number of samples of a given bandwidth.…”

Section: Discussionmentioning

confidence: 99%

Discrete Fourier transform and cepstrum analysis of vibration events on semi-trailer truck

Pidl¹,

Böröcz²

2019

FME Transactions

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The aim of this paper is to present a novel techniqe to analyse the vibration signals during transportation in order to give new information to engineers to better understand these physical events. One of the primary sources of damages during transportation is the permanent vibration transmitted from the platform of semi-trailer to the cargo. The nature of this vibration depends on the road conditions and the features of the vehicle. In this study, a 2-axle-truck with a 3-axle-semi-trailer equipped with air spring suspension was observed to analyse the vibration circumstances. The affecting factors during the transportation were the type of the road (motorway, primary road, secondary road, tertiary road), and different vehicle speed levels. The vibration events were measured and registered on the platform of the trailer, then these values were evaluated in MATLAB environment. The presence of the harmonic vibrational components, the stationarity of the mode shapes, the characteristic frequency narrow-bands of the RMS and PSD values were primarily studied. The applied methods that were used are: discrete Fourier transformation, autocorrelation-, cross-correlation functions and cepstrum analysis.

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“…The non‐Gaussian nature of acceleration levels has also been proven through an analysis of rail transport by P. Böröcz and S. P. Singh . Very recently, the analysis of the recordings of small trucks transport by P. Böröcz has proven that the cumulative distribution function of the acceleration levels is optimally fitted with a 2‐parameter Weibull distribution …”

Section: State Of the Artmentioning

confidence: 95%

“…12 Very recently, the analysis of the recordings of small trucks transport by P. Böröcz has proven that the cumulative distribution function of the acceleration levels is optimally fitted with a 2-parameter Weibull distribution. 13 V. Rouillard V. Rouillard and M. A. Sek 15 later improved this method by considering the magnitude peak/valley value so as to identify the significant variations in the signal. The algorithm developed by the authors considers the difference between the vibration intensity value and the magnitude peak/valley value.…”

Section: State Of the Artmentioning

confidence: 99%

Decomposition of the acceleration levels distribution of a road transport into a sum of weighted Gaussians: Application to vibration tests

Bonnin

Nolot

Huart³

et al. 2018

Packag Technol Sci

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The usual method to simulate vertical vibrations generated by road transport in laboratory is to use the average power spectral density. With this method, the distribution of the acceleration levels throughout the test is a Gaussian which does not conform to the reality of a transport. This study proposes an improvement of the classical method; this improvement permits to simulate the power spectral density and the distribution of acceleration levels by using a conventional device. The main idea of this method is to decompose the distribution of an actual road transport by using a sum of weighted Gaussians. Then, we apply the power spectral density with the root mean square acceleration (grms) level and duration corresponding to each Gaussian calculated from the weighted sum. We show that the weighting coefficients correspond to the time fraction of the test. Over the total duration of the test, we then retrieve the acceleration levels distribution of the actual transport. This new test method is experimentally validated with 2 examples of actual transports.

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Averaged vibration levels during courier parcel delivery service in small truck in Hungary

Cited by 9 publications

References 16 publications

Experimental Comparison of Field and Accelerated Random Vertical Vibration Levels of Stacked Packages for Small Parcel Delivery Shipments

Experimental Comparison of Field and Accelerated Random Vertical Vibration Levels of Stacked Packages for Small Parcel Delivery Shipments

Discrete Fourier transform and cepstrum analysis of vibration events on semi-trailer truck

Decomposition of the acceleration levels distribution of a road transport into a sum of weighted Gaussians: Application to vibration tests

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