scholarly journals Dynamic Stiffness of Bituminous Mixtures for the Wearing Course of the Road Pavement—A Proposed Method of Measurement

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1973
Author(s):  
Krzysztof Robert Czech ◽  
Wladyslaw Gardziejczyk
Keyword(s):  
Dynamic Properties ◽  
Dynamic Stiffness ◽  
Physical And Mechanical Properties ◽  
Test Stand ◽  
Traffic Load ◽  
Road Noise ◽  
The Road ◽  
Bituminous Mixtures ◽  
Signal Amplifier

Stiffness is an important mechanical characteristic of asphalt mixtures used in the wearing course. It is one of the determining factors in the generation of tyre/road noise. The dynamic stiffness of the upper layer of the road surface depends on the physical and mechanical properties of the materials it is composed of, and traffic load. Determination of dynamic stiffness, both in laboratory conditions and in situ, requires consideration of many other factors. Tests of dynamic properties of road surfaces in field conditions are most often conducted with the help of modal hammers. Impulse excitation results are usually less accurate than those in the application of modal exciters. The test stand was constructed, comprising a tripod, 32-channel and 24-bit data acquisition system, exciter, signal amplifier, impedance head, single-axis piezoelectric accelerometers and a stinger. The test stand and the proposed method of measuring dynamic stiffness do not require the determination of the resonance frequency of the tested specimen and can be used both on various types of bituminous mixtures of varying shape and dimensions, as well as directly on the upper surface of the wearing course of bituminous pavements. The test results showed that the type of bituminous mixture used in the wearing course significantly affects its dynamic stiffness. The dynamic stiffness level of asphalt concrete, stone mastic asphalt and porous asphalt layers was determined to be similar. The addition of rubber granulates significantly reduced its rigidity, which is very beneficial from the point of view of reducing the tyre/road noise.

Derivation of road noise improvement factor within a suspension system using the inverse substructuring method

2019 ◽  
Vol 233 (14) ◽  
pp. 3775-3786 ◽  
Author(s):  
Yeon June Kang ◽  
Jun Gu Kim ◽  
David P Song ◽  
Kang Duck Ih
Keyword(s):  
Frequency Response ◽  
Response Function ◽  
Frequency Response Function ◽  
Dynamic Properties ◽  
Dynamic Stiffness ◽  
The Body ◽  
Road Noise ◽  
Input Force ◽  
Improvement Factor ◽  
Cross Member

This research aims to develop a method to efficiently reduce the body input force from the chassis due to road-induced excitation. To this end, the frequency response function–based substructuring method is employed to model the vehicle cross member and coupling points. Using this model, the dynamic stiffness modification factor of elastic bushing at the effective path is predicted for reducing road noise. Because of the difficulties in directly obtaining dynamic properties of body mount bushings pressured into the sub-frame, the frequency response function–based substructuring model and inverse formulation method are used to indirectly estimate the bushing’s dynamic properties. Therefore, the primary focus of this study is to validate the feasibility of using the inverse formulation method for deriving road noise improvement factor on a simple cross member application. In this feasibility validation, road excitation is simply substituted with a shaker excitation in vertical direction. The previously developed suspension rig that enables a direct measurement of the body input force at the coupling points and the specially developed cross member jig are used for the validation test.

scholarly journals Cast Iron And Mineral Cast Applied For Machine Tool Bed - Dynamic Behavior Analysis

2015 ◽  
Vol 60 (2) ◽  
pp. 1023-1029 ◽  
Author(s):  
N. Kępczak ◽  
W. Pawłowski ◽  
Ł. Kaczmarek
Keyword(s):  
Cast Iron ◽  
Machine Tool ◽  
Machine Tools ◽  
Dynamic Properties ◽  
Dynamic Stiffness ◽  
Physical And Mechanical Properties ◽  
Strength Properties ◽  
Structural Elements ◽  
Static Structure ◽  
Static Rigidity

Abstract Cast iron and mineral cast are the materials most often used in the machine structural elements design (bodies, housings, machine tools beds etc.). The materials significantly differ in physical and mechanical properties. The ability to suppress vibration is one of the most important factors determining the dynamic properties of the machine and has a significant impact on the machining capabilities of a machine tool. Recent research and development trends show that there is a clear tendency to move away from the traditional iron casting to the mineral casting, due to better dynamic properties of the latter. However mineral cast as a structural material for the whole machine tools bed turns out to be insufficient due to its poor mechanical strength properties. The best solution should benefit from the advantages of the cast iron and mineral cast materials while minimizing their drawbacks. The paper presents numerical modal analysis of two lathe beds: the first one made of gray cast iron and the second one made of hybrid connection of cast iron and mineral cast. The analysis was conducted in order to determine the dynamic properties of two bodies of similar shapes made in the traditional (cast iron) and innovative hybrid (cast iron and mineral cast) technology. In addition, an analysis of the static structure rigidity of the two beds was performed. During the simulation studies it was found a significant increase in dynamic stiffness and static rigidity of the machine tool body made of hybrid connection of cast iron and mineral cast. The results of numerical simulations have confirmed the desirability of using hybrid construction because the dynamic properties of such a body are more advantageous in comparison with the conventional body made of cast iron.

scholarly journals Determination of the Chemical, Physical and Mechanical Characteristics of Electric Arc Furnace Slags and Environmental Evaluation of the Process for Their Utilization as an Aggregate in Bituminous Mixtures

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 782 ◽  
Author(s):  
Juan María Terrones-Saeta ◽  
Jorge Suárez-Macías ◽  
Evaristo Rafael Moreno-López ◽  
Francisco Antonio Corpas-Iglesias
Keyword(s):  
Raw Materials ◽  
Physical And Mechanical Properties ◽  
Road Construction ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Arc Furnace ◽  
Environmental Evaluation ◽  
Bituminous Mixtures ◽  
Electric Arc Furnace Slag

Road construction is an activity that demands a significant amount of aggregates for bituminous mixtures. In addition, these aggregates must be of a suitable quality for use, even more so on high traffic roads. In response to this problem, and in order to avoid the extraction of new raw materials, research is being carried out using industrial waste as a substitute for conventional aggregates. In this way, the extraction of raw materials is reduced and landfilling of waste is avoided. However, these wastes must have certain properties and environmental advantages over natural aggregates. Otherwise, the use of waste would not be environmentally beneficial but would be more damaging to the environment. For this reason, this research evaluates the viability of using electric arc furnace slag as aggregates for bituminous mixtures, the main objectives being the determination of the characteristics of the by-product, the particularities and the critical points to be taken into account for its subsequent use in mixtures. At the same time, the environmental advantages of treating this waste to obtain a usable aggregate are evaluated in comparison with the processing of a natural aggregate. The results showed that electric arc furnace slags have a suitable chemical composition and excellent physical and mechanical properties for use in bituminous mixtures, even on high traffic roads. At the same time, it was determined that their use produces a considerable reduction in environmental afflictions. Therefore, it could be affirmed that the use of electric arc furnace slags in bituminous mixtures is recommendable as a way to develop more sustainable materials for construction.

scholarly journals Analysis of the Impact of no Passing Zones on Fuel Costs

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Nenad Ruškić ◽  
Tea Pavlica ◽  
Jelena Nišić
Keyword(s):  
Road Network ◽  
Traffic Load ◽  
Level Of Service ◽  
The Road ◽  
Road Section ◽  
Traffic Volumes ◽  
Clear Visibility ◽  
The Impact ◽  
Fuel Costs

The primary task of traffic and transportation planning is to improve the conditions of traffic and level of service on the entire road network. On three sections, which were analyzed in this paper, the possibility of reducing the precentage of no passing zones was noticed, by changing the horizontal signalization on the segments of road section where the clear visibility for overtaking was determined for one direction of the two-way highway. In the first part of the paper, the analysis of traffic conditions on the existing and on the newly designed variants of all three observed road sections was performed. Analysis of the level of service on the intersections that are part of this research are done in chapter 2. Increasing the speed on the newly designed section results in a reduced travel time and this leads to savings in fuel costs as shown in chapter 3. Traffic forecast for the planning 2029 is done in chapter 4, the forecasted traffic load implies future traffic volumes for which adequate capacities of the road network need to be provided. Chapter 5 is based on determination of the relationship between the benefits brought by the newly designed variant and the costs that are realized during its construction. The results of this analysis were used as input data for the economic evaluation of the project solutions, where the savings in fuel costs were analyzed.

scholarly journals ANALYSIS OF THE VIBRATION IMPACT ON THE SOILS OF VASILYEVSKY ISLAND OF ST. PETERSBURG

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 332-334
Author(s):  
Violetta Izotova ◽  
Ksenia Pankratova ◽  
Georgy Pospehov
Keyword(s):  
Dynamic Instability ◽  
Dynamic Properties ◽  
Physical And Mechanical Properties ◽  
Dynamic Loads ◽  
Mining Institute ◽  
Central Section ◽  
Vibration Impact ◽  
Quantitative Analyses ◽  
First Time

The development of St. Petersburg is accompanied by an increase in dynamic loads. For example, in 2016, the opening of the central section of the Western-Speed Diameter highway in planned to open. Moreover it is planned to open the Mining Institute, Gavan and Marine Facade metro stations in this area. The question about the prediction of the dynamic instability of the soils needs further investigations, as it requires not only an accurate assessment of the loads, but also reliable modeling of changing the physical and mechanical properties of the soils. In 2015 for the first time the sate standard "Methods of laboratory determination of dynamic properties of dispersed soils" was introduced only in Russia. At the same time, the document does not regulate the choice of test schemes and modes for a specific type of soil, asnd there are no recommendations in the existing construction rules on the application of the obtained results of soil tests. In this paper, quantitative analyses of the properties of the vibrational field on the territory of Vasilievsky Island of St. Petersburg were done. Considered sources of vibration. ANalyzed characteristics of the sources, such as: metro, trams, automobiles.

Determination of Combined and Second Order Factor Effects for Simultaneous Optimization of Physical and Mechanical Properties of NR/BR Blend System

2014 ◽  
Vol 42 (4) ◽  
pp. 290-304
Author(s):  
Rajarajan Aiyengar ◽  
Jyoti Divecha
Keyword(s):  
Physical And Mechanical Properties ◽  
Second Order ◽  
Simultaneous Optimization ◽  
Order Effects ◽  
Elongation At Break ◽  
Five Factors ◽  
Rubber Compounds ◽  
Polybutadiene Rubber ◽  
Contour Plots

ABSTRACT The blends of natural rubber (NR), polybutadiene rubber (BR), and other forms of rubbers are widely used for enhancing the mechanical and physical properties of rubber compounds. Lots of work has been done in conditioning and mixing of NR/BR blends to improve the properties of its rubber compounds and end products such as tire tread. This article employs response surface methodology designed experiments in five factors; high abrasion furnace carbon black (N 330), aromatic oil, NR/BR ratio, sulfur, and N-oxydiethylene-2-benzothiazole sulfenamide for determination of combined and second order effects of the significant factors leading to simultaneous optimization of the NR/BR blend system. One of the overall optimum of eight properties existed at carbon 44 phr, oil 6.1 phr, NR/BR 78/22 phr with the following values of properties: tensile strength (22 MPa), elongation at break (528%), tear resistance (30 kg/mm), rebound resilience (67%), moderate hardness (68 International rubber hardness degrees) with low heat buildup (17 °C), permanent set (12%), and abrasion loss (57 mm3). More optimum combinations can easily be determined from the NR/BR blend system models contour plots.

Basic set of experiments for determination of mechanical properties of sand

2014 ◽  
Vol 62 (1) ◽  
pp. 129-137
Author(s):  
A. Sawicki ◽  
J. Mierczyński
Keyword(s):  
Mechanical Properties ◽  
Soil Mechanics ◽  
Physical And Mechanical Properties ◽  
Local Strain ◽  
Initial State ◽  
Laboratory Equipment ◽  
Additional Information ◽  
Basic Set ◽  
Initial Anisotropy

Abstract A basic set of experiments for the determination of mechanical properties of sands is described. This includes the determination of basic physical and mechanical properties, as conventionally applied in soil mechanics, as well as some additional experiments, which provide further information on mechanical properties of granular soils. These additional experiments allow for determination of steady state and instability lines, stress-strain relations for isotropic loading and pure shearing, and simple cyclic shearing tests. Unconventional oedometric experiments are also presented. Necessary laboratory equipment is described, which includes a triaxial apparatus equipped with local strain gauges, an oedometer capable of measuring lateral stresses and a simple cyclic shearing apparatus. The above experiments provide additional information on soil’s properties, which is useful in studying the following phenomena: pre-failure deformations of sand including cyclic loading compaction, pore-pressure generation and liquefaction, both static and caused by cyclic loadings, the effect of sand initial anisotropy and various instabilities. An important feature of the experiments described is that they make it possible to determine the initial state of sand, defined as either contractive or dilative. Experimental results for the “Gdynia” model sand are shown.

Automation of selected brazes' dynamic properties in high-temperatures' measurement process

2013 ◽  
Vol 18 (2-3) ◽  
pp. 33-41
Author(s):  
Dominik Sankowski ◽  
Marcin Bakala ◽  
Rafał Wojciechowski
Keyword(s):  
Surface Tension ◽  
High Temperatures ◽  
Dynamic Properties ◽  
Automatic Measurement ◽  
Measurement Methodology ◽  
Joining Process ◽  
Wetting Force ◽  
Research Grant

Abstract The good quality of several manufactured components frequently depends on solidliquid interactions existing during processing. Nowadays, the research in material engineering focuses also on modern, automatic measurement methods of joining process properties, i.a. wetting force and surface tension, which allows for quantitative determination of above mentioned parameters. In the paper, the brazes’ dynamic properties in high-temperatures’ measurement methodology and the stand for automatic determination of braze’s properties, constructed and implmented within the research grant nr KBN N N519 441 839 - An integrated platform for automatic measurement of wettability and surface tension of solders at high temperatures, are widely described

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