scholarly journals International Standards Organization-Compatible Index for Pavement Roughness

1998 ◽  
Vol 1643 (1) ◽  
pp. 110-115 ◽  
Author(s):  
A. T. Papagiannakis ◽  
B. Raveendran
Keyword(s):  
Unit Length ◽  
International Standards ◽  
Whole Body ◽  
User Cost ◽  
Pavement Roughness ◽  
Power Spectral ◽  
Reference Vehicle ◽  
Roughness Index ◽  
Pavement Damage ◽  
International Standards Organization

The development of a new pavement roughness index, which is compatible to the current International Standards Organization (ISO) standard on “exposure to whole-body vibration” is described. The index was intended to be the independent variable in the future development of relationships between user cost (i.e., vehicle depreciation, repairs, discomfort and so on) and pavement roughness; hence it was named RIDE (Roughness Index for Driving Expenditure). RIDE is based on the sprung mass acceleration response of a reference vehicle to the pavement profile. It is calculated in the frequency domain by multiplying the power spectral density (PSD) of the pavement profile by the square of the transfer function of the sprung mass acceleration of the reference vehicle. The resulting sprung mass acceleration PSD is integrated over frequency to yield the root-mean-square of the sprung mass acceleration per unit length of pavement traveled. The sprung mass acceleration is shown to be the main contributor of dynamic axle loads in heavy trucks, which relate to vehicle and cargo damage and also to pavement damage.

On Using the ISO Standard To Evaluate the Ride Quality of Broad-Band Vibration Spectra in Transportation Vehicles

1976 ◽  
Vol 98 (4) ◽  
pp. 440-443 ◽  
Author(s):  
Craig C. Smith
Keyword(s):  
Broad Band ◽  
International Standards ◽  
Whole Body ◽  
Ride Quality ◽  
Iso Standard ◽  
Vibration Data ◽  
Power Spectral ◽  
Country Road ◽  
International Standards Organization ◽  
Iso 2631

The International Standards Organization “Guide for the Evaluation of Human Exposure to Whole-Body Vibrations”, ISO 2631, is converted to a form usable for direct comparison with vibration data represented in power spectral density form. Comparisons are made between the ISO standard, the Urban Tracked Air Cushion Vehicle (UTACV) specification, and measured vibrations at the floorboard and seat of an automobile over smooth and rough roads. The data indicate that the ISO standard is less restrictive than the UTACV specification, and generally not restrictive enough to indicate the roughness of an automobile ride on a rough country road.

Relationship between International Roughness Index and Power Spectral Density of Asphalt Pavements in China

2013 ◽  
Vol 742 ◽  
pp. 104-108
Author(s):  
Shao Wen Liu ◽  
Xiao Zhang
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Response Function ◽  
Asphalt Pavements ◽  
International Roughness Index ◽  
Quarter Car Model ◽  
Pavement Roughness ◽  
Power Spectral ◽  
Roughness Index ◽  
Quarter Car

In this paper, pavement roughness is assumed as random stationary variable and used as the exciting force of theoretical analyses of the quarter car model of International Roughness Index (IRI). From the frequency response function of the quarter car, the response function of the displacement difference between sprung and unsprung mass is obtained based on random process theory. Then the relationship between IRI and power spectral density (PSD) is established from statement characteristic of the response function. Finally, the longitudinal road profiles of typical asphalt roads in China are used to validate the proposed model.

scholarly journals Development, validation, and pilot MRI safety study of a high-resolution, open source, whole body pediatric numerical simulation model

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0241682
Author(s):  
Hongbae Jeong ◽  
Georgios Ntolkeras ◽  
Michel Alhilani ◽  
Seyed Reza Atefi ◽  
Lilla Zöllei ◽  
...  
Keyword(s):  
Brain Structures ◽  
International Standards ◽  
Whole Body ◽  
Synthetic Image ◽  
Mri Safety ◽  
Older Children ◽  
Implantable Medical Device ◽  
Tissue Compartments ◽  
International Standards Organization ◽  
Age Range

Numerical body models of children are used for designing medical devices, including but not limited to optical imaging, ultrasound, CT, EEG/MEG, and MRI. These models are used in many clinical and neuroscience research applications, such as radiation safety dosimetric studies and source localization. Although several such adult models have been reported, there are few reports of full-body pediatric models, and those described have several limitations. Some, for example, are either morphed from older children or do not have detailed segmentations. Here, we introduce a 29-month-old male whole-body native numerical model, “MARTIN”, that includes 28 head and 86 body tissue compartments, segmented directly from the high spatial resolution MRI and CT images. An advanced auto-segmentation tool was used for the deep-brain structures, whereas 3D Slicer was used to segment the non-brain structures and to refine the segmentation for all of the tissue compartments. Our MARTIN model was developed and validated using three separate approaches, through an iterative process, as follows. First, the calculated volumes, weights, and dimensions of selected structures were adjusted and confirmed to be within 6% of the literature values for the 2-3-year-old age-range. Second, all structural segmentations were adjusted and confirmed by two experienced, sub-specialty certified neuro-radiologists, also through an interactive process. Third, an additional validation was performed with a Bloch simulator to create synthetic MR image from our MARTIN model and compare the image contrast of the resulting synthetic image with that of the original MRI data; this resulted in a “structural resemblance” index of 0.97. Finally, we used our model to perform pilot MRI safety simulations of an Active Implantable Medical Device (AIMD) using a commercially available software platform (Sim4Life), incorporating the latest International Standards Organization guidelines. This model will be made available on the Athinoula A. Martinos Center for Biomedical Imaging website.

scholarly journals Roughness-Induced Pavement–Vehicle Interactions

2015 ◽  
Vol 2525 (1) ◽  
pp. 62-70 ◽  
Author(s):  
Arghavan Louhghalam ◽  
Mehdi Akbarian ◽  
Franz-Joseph Ulm
Keyword(s):  
Fuel Consumption ◽  
Mechanistic Model ◽  
Rolling Resistance ◽  
Thermodynamic Quantity ◽  
Surface Characteristics ◽  
Density Parameter ◽  
Pavement Roughness ◽  
Power Spectral ◽  
Roughness Index ◽  
The Impact

Pavement roughness affects rolling resistance and thus vehicle fuel consumption. When a vehicle travels at constant speed on an uneven road surface, the mechanical work dissipated in the vehicle's suspension system is compensated by vehicle engine power and results in excess fuel consumption. This dissipation depends on both road roughness and vehicle dynamic characteristics. This paper proposes, calibrates, and implements a mechanistic model for roughness-induced dissipation. The distinguishing feature of the model is its combination of a thermodynamic quantity (energy dissipation) with results from random vibration theory to identify the governing parameters that drive the excess fuel consumption caused by pavement roughness, namely, the international roughness index (IRI) and the waviness number, w (a power spectral density parameter). It is shown through sensitivity analysis that the sensitivity of model output, that is, excess fuel consumption, to the waviness number is significant and comparable to that of IRI. Thus, introducing the waviness number as a second roughness index, in addition to IRI, allows a more accurate quantification of the impact of surface characteristics on vehicle fuel consumption and the corresponding greenhouse gas emissions. This aspect is illustrated by application of the roughness–fuel consumption model to two road profiles extracted from FHWA's Long-Term Pavement Performance database.

scholarly journals Evaluation of the methodologies used to generate random pavement profiles based on the power spectral density: An approach based on the International Roughness Index

2017 ◽  
Vol 37 (1) ◽  
pp. 49 ◽  
Author(s):  
Boris Jesús Goenaga ◽  
Luis Guillermo Fuentes Pumarejo ◽  
Otto Andrés Mora Lerma
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Pavement Management ◽  
Dynamic Loads ◽  
International Roughness Index ◽  
Vertical Excitation ◽  
Shaping Filter ◽  
Pavement Roughness ◽  
Power Spectral ◽  
Roughness Index

The pavement roughness is the main variable that produces the vertical excitation in vehicles. Pavement profiles are the main determinant of (i) discomfort perception on users and (ii) dynamic loads generated at the tire-pavement interface, hence its evaluation constitutes an essential step on a Pavement Management System. The present document evaluates two specific techniques used to simulate pavement profiles; these are the shaping filter and the sinusoidal approach, both based on the Power Spectral Density. Pavement roughness was evaluated using the International Roughness Index (IRI), which represents the most used index to characterize longitudinal road profiles. Appropriate parameters were defined in the simulation process to obtain pavement profiles with specific ranges of IRI values using both simulation techniques. The results suggest that using a sinusoidal approach one can generate random profiles with IRI values that are representative of different road types, therefore, one could generate a profile for a paved or an unpaved road, representing all the proposed categories defined by ISO 8608 standard. On the other hand, to obtain similar results using the shaping filter approximation a modification in the simulation parameters is necessary. The new proposed values allow one to generate pavement profiles with high levels of roughness, covering a wider range of surface types. Finally, the results of the current investigation could be used to further improve our understanding on the effect of pavement roughness on tire pavement interaction. The evaluated methodologies could be used to generate random profiles with specific levels of roughness to assess its effect on dynamic loads generated at the tire-pavement interface and user’s perception of road condition.

scholarly journals Serrated Chips Formation in Micro Orthogonal Cutting of Ti6Al4V Alloys with Equiaxial and Martensitic Microstructures

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 197 ◽  
Author(s):  
ZeJia Zhao ◽  
Suet To ◽  
ZhuoXuan Zhuang
Keyword(s):  
Cutting Force ◽  
Unit Length ◽  
Orthogonal Cutting ◽  
Machining Process ◽  
Orthogonal Machining ◽  
Large Yield ◽  
Power Spectral ◽  
Straight Line ◽  
Serrated Chips ◽  
Electropulsing Treatment

The formation of serrated chips is an important feature during machining of difficult-to-cut materials, such as titanium alloy, nickel based alloy, and some steels. In this study, Ti6Al4V alloys with equiaxial and acicular martensitic microstructures were adopted to analyze the effects of material structures on the formation of serrated chips in straight line micro orthogonal machining. The martensitic alloy was obtained using highly efficient electropulsing treatment (EPT) followed by water quenching. The results showed that serrated chips could be formed on both Ti6Al4V alloys, however the chip features varied with material microstructures. The number of chip segments per unit length of the alloy with martensite was more than that of the equiaxial alloy due to poor ductility. Besides, the average cutting and thrust forces were about 8.41 and 4.53 N, respectively, for the equiaxed Ti6Al4V alloys, which were consistently lower than those with a martensitic structure. The high cutting force of martensitic alloy is because of the large yield stress required to overcome plastic deformation, and this force is also significantly affected by the orientations of the martensite. Power spectral density (PSD) analyses indicated that the characteristic frequency of cutting force variation of the equiaxed alloy ranged from 100 to 200 Hz, while it ranged from 200 to 400 Hz for workpieces with martensites, which was supposedly due to the formation of serrated chips during the machining process.

ISO Human-Computer Interaction Standards: Finding Them and What They Contain

2020 ◽  
Vol 64 (1) ◽  
pp. 400-404
Author(s):  
Paul Green
Keyword(s):  
Human Computer Interaction ◽  
Systems Engineering ◽  
User Interfaces ◽  
Task Force ◽  
Technical Committee ◽  
International Standards ◽  
Human System ◽  
International Standards Organization ◽  
Browsing Tool ◽  
Computer Interaction

An HFES Task Force is considering if, when, and which, HFES research publications should require the citation of relevant standards, policies, and practices to help translate research into practice. To support the Task Force activities, papers and reports are being written about how to find relevant standards produced by various organizations (e.g., the International Standards Organization, ISO) and the content of those standards. This paper describes the human-computer interaction standards being produced by ISO/IEC Joint Technical Committee 1 (Information Technology). Subcommittees 7 (Software and Systems Engineering) and 35 (User Interfaces), and Technical Committee 159, Subcommittee 4 (Ergonomics of Human-System Interaction), in particular, the contents of the ISO 9241 series and the ISO 2506x series. Also included are instructions on how to find standards using the ISO Browsing Tool and Technical Committee listings, and references to other materials on finding standards and standards-related teaching materials.

A Methodology for the Test Design and Evaluation of Human Whole-Body Vibration in Ground Vehicle Systems

1989 ◽  
Vol 33 (18) ◽  
pp. 1192-1196
Author(s):  
Ellen C. Haas
Keyword(s):  
Whole Body Vibration ◽  
International Standards ◽  
Whole Body ◽  
Test Design ◽  
Exposure Limits ◽  
Ground Vehicle ◽  
Body Vibration ◽  
Exposure Limit ◽  
Vehicle Systems ◽  
Iso 2631

To date, testing and evaluation of whole-body vibration in ground vehicle systems have not always fully utilized appropriate experimental design methodology, applicable statistical tests, or relevant criteria. A test design and evaluation methodology was developed to eliminate these oversights. This methodology uses inferential statistics, questionnaires, and a comparison of vibration data with representative mission scenarios. The methodology was employed in the evaluation of two alternative tracked ground vehicle designs. The independent variables were track type, terrain, vehicle speed, and crew position. The dependent variables were International Standards Organization (ISO) 2631 whole-body vibration exposure limit times at the lateral, transverse, and vertical axes. Two different multivariate analyses of variance (MANOVAs) performed on the exposure limit data indicated that all main effects, as well as several interactions, were significant (p < .01). A comparison of exposure limits to a representative mission scenario indicated that both track types would exceed ISO 2631 exposure, comfort, and fatigue limits during expected travel over cross-country terrain. Crew questionnaires also indicated crew discomfort when exposed to this type of terrain. The experiment demonstrated that the procedure was useful in helping to determine the extent that vehicle vibration permits the performance of the vehicle mission, within limits dictated by safety, efficiency, and comfort.

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