scholarly journals Numerical analysis of asphalt concrete milling process based on multicomponent modeling

2020 ◽  
Author(s):  
Liqun Zhou ◽  
Yi Liu ◽  
Zhennan Wang ◽  
Yuping Li ◽  
Kui Zhang ◽  
...  

Abstract In this paper, according to the different physical properties of each component of asphalt concrete, a finite element simulation is used to build a mechanical constitutive model for the concrete cutting processes. When the machine cutter contacts different aggregate particles, the variation rules of mechanical information are obtained and studied. The main research work includes: (1) The track and force of the tool in the cutting process are defined, and then the track equation of the tool tip and the calculation formula of friction resistance are obtained. The relationship between the friction resistance and working parameters is clarified. (2)From the multicompont modeling, the internal components of asphalt concrete are refined, and the mechanical properties of asphalt mortar and aggregate particles are set up. Random feeding of different aggregate particles in asphalt concrete specimens is completed by using Python software and Monte carlo method. After the simulation, the results are imported into numerical software to generate the variation curve of tool friction resistance, so as to obtain the rule of its change with various factors, and according to the above studies, the optimal working parameters combination of the milling planer are summarized.

Author(s):  
M Pogacnik ◽  
J Kopac

The process of turn-milling was a subject of intensive research in the late 1980s, which was followed by a number of practical applications. However, this process has not been investigated as extensively as other conventional cutting processes (turning). The main limitations preventing wider use have been the kinematics (smaller shape elements) and the dynamic instability. This paper presents guidelines showing how to avoid dynamic instability by using optimum entry—exit conditions which can be achieved through a proper set-up of the process parameters. As a result, a decision diagram is proposed. The paper also presents the results of comparison with turning, showing that, at the same productivity, turn-milling enables better surface roughness and is much more suitable for high-speed cutting (HSC) machining than turning, where the centrifugal force restrains the process.


Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 799
Author(s):  
Justyna Miedzianowska ◽  
Marcin Masłowski ◽  
Przemysław Rybiński ◽  
Krzysztof Strzelec

Increasingly, raw materials of natural origin are used as fillers in polymer composites. Such biocomposites have satisfactory properties. To ensure above-average functional properties, modifications of biofillers with other materials are also used. The presented research work aimed to produce and characterize elastomeric materials with a straw-based filler and four different types of montmorillonite. The main research goal was to obtain improved functional parameters of vulcanizates based on natural rubber. A series of composites filled with straw and certain types of modified and unmodified nano-clays in various ratios and amounts were prepared. Then, they were subjected to a series of tests to assess the impact of the hybrids used on the final product. It has been shown that the addition of optimal amounts of biofillers can, inter alia, increase the tensile strength of the composite, improve damping properties, extend the burning time of the material and affect the course of vulcanization or cross-linking density.


2021 ◽  
Vol 46 (1) ◽  
pp. 41-47
Author(s):  
G. Meldesh ◽  

The article put attention on the need for a methodological collaboration analysis of the academic and modern types of teaching sculpture in the specialized creative colleges and universities of the Republic of Kazakhstan in the modern educational and aesthetic discourse. The main research problem focuses on identifying and characterizing the most relevant educational theoretical and practical methods that can significantly increase the level of domestic art education in the art of sculpture. The author believes that a comprehensive scientific analysis of the educational potential of the Kazakhstani aesthetic originality of modern sculpture, its history and technical and technological features will give a possibility to understand deeply and see the big picture of the art education role in the general socio-cultural canvas of sovereign Kazakhstan. At the moment, the Kazakhstani art education system is on a peripeteia and it is necessary to clear the choice between academic and contemporary art practices or their harmonious synthesis. This work is devoted to these question’s analysis and the author's research work disclosure.


2011 ◽  
Vol 148-149 ◽  
pp. 1319-1322
Author(s):  
Xiao Hu ◽  
Yi Sheng Zhang ◽  
Hong Qing Li ◽  
De Qun Li

Blow forming process of plastic sheets is simple and easy to realize, thus, it is widely used for plastic thin-wall parts. In the practical production, an effective method is needed for the preliminary set-up of process parameters in order to achieve accurate control of thickness distribution. Thus, a finite element method (FEM) code is used to simulate blow forming process. For better description of complex material theological characteristics, a physically based viscoelastic model (VUMAT forms Buckley model) to model the complex constitutive behavior is used. Nonlinear FE analyses using ABAQUS were carried out to simulate the blow forming process of plastic cups. The actual values at different locations show a satisfactory agreement with the simulation results: as a matter of fact the error along the cell mid-section did not exceed 0.02 mm on average, corresponding to 5% of the initial thickness, thus the FE model this paper can meet the requirements of the engineering practice.


2017 ◽  
Vol 869 ◽  
pp. 50-61
Author(s):  
Matthias Sabel ◽  
Christian Sator ◽  
Ralf Müller ◽  
Benjamin Kirsch

The formation of chips in cutting processes is characterised by large deformations and large configurational changes and therefore challenges established modeling techniques. To overcome these difficulties, the particle finite element method (PFEM) combines the benefits of discrete modeling techniques with methods based on continuum mechanics. In this work an outline of the PFEM, as well as an explanation of the finite element formulation are provided. The impact of the boundary detection on the structural integrity is studied. The numerical examples include a tensile test as well as cutting simulations. The paper is concluded by a comparison of cutting forces with analytical results.


2021 ◽  
pp. 6-20
Author(s):  
П.Я. БАКЛАНОВ ◽  
А.В. МОШКОВ

В статье приводится характеристика основных этапов развития экономико-географических исследований в Тихоокеанском институте географии с момента его организации. Выделено 5 этапов и представлены наиболее важные результаты экономико-географических исследований, полученных в лаборатории территориально-хозяйственных структур за 50 лет. Научные направления исследований определялись общими задачами, решаемыми Тихоокеанским институтом географии, в первую очередь это комплексные прогнозно-географические исследования разномасштабных геосистем Дальнего Востока России в контактной зоне «суша–океан». В основу выделения этапов исследований положены изменения тем научно-исследовательской работы лаборатории. Основным направлением в течение большого периода времени было изучение разноранговых территориально-хозяйственных структур Дальнего Востока, географических, в т.ч. природно-ресурсных, и геополитических факторов их развития. Изложены основные результаты, полученные сотрудниками лаборатории на разных этапах, в т.ч. теоретических и методологических исследований географического пространства и разноранговых пространственных систем, географических и геополитических факторов формирования разноранговых территориально-хозяйственных структур, в том числе трансграничных и аква-территориальных, разработки предложений для Программ устойчивого развития регионов, методов исследования производственно-природных отношений в локальных и районных территориально-производственных системах, оценки территориальных сочетаний природных ресурсов, изучения особенностей трансформации территориально-отраслевых структур, районирования территории и прибрежной акватории Дальнего Востока и т.д. Отдельные экономико-географические исследования имеют и большое практическое значение. В первую очередь, это разработанные в лаборатории предложения для Стратегий и Программ социально-экономического развития Дальнего Востока, Приморского края, агломерации Владивостока и других территорий. The article describes the main stages in the development of economic - geographical research at the Pacific Institute of Geography (now Pacific Geographical Institute) since its organization. The authors identified five such stages and presented the most important results of economic and geographical research accomplished in their laboratory of spatial-economic structures for 50 years. Scientific directions of these researches were determined by the general tasks solved by the Pacific Geographical Institute, in first turn, comprehensive forecasting and geographical research of different-scale geosystems of the Far East of Russia in the ‘land-ocean’ contact zone. The selection of the research stages was based on changes in the topics of the laboratory’s research work. For a long time its main topic was in the studies of multi-ranked territorial and economic structures of the Far East, and geographical factors of their development including natural resource and geopolitical ones. The main research activities of the laboratory staff at different stages included theoretical and methodological studies of geographic space and different-ranked spatial systems; geographical and geopolitical factors in the formation of multi-ranked territorial and economic structures, including transboundary and aqua-territorial ones; working out of proposals to the state programs of the sustainable development of regions; methods of researching the productive-natural relations in local and regional territorial-production systems; assessing the territorial combinations of natural resources; studying the features of the transformation of territorial and sectoral structures; zoning the territory and coastal waters of the Far East, etc. Separate economic and geographical studies are also of great practical importance. In first turn, there are proposals developed in the laboratory for strategies and programs of the socio-economic development of the Far East, Primorsky Kray, Vladivostok agglomeration and other territories.


Author(s):  
David Airehrour ◽  
Jairo Guttierrez ◽  
Sayan Kumar Ray

The routing protocol for low-power and lossy networks (RPL) has gained prominence as the standard IoT routing protocol. However, it faces like many other routing protocols diverse attacks. Many studies have been proposed to secure the RPL protocol, and simulation studies have been put forward as the main research method, while testbed experiments, though an authentic research and testing method, have been ignored. Although testbed experiments and simulation studies have their strengths and limitations, testbed techniques could be used as a verifiable validation method for simulation studies. This study is a follow up research work to validate our simulation study, which addressed Blackhole attacks in the RPL routing protocol. In addition, Selective Forwarding attacks are also addressed. It implements a testbed while embedding our Trust-based RPL protocol and the standard RPL protocol in a smart environment configuration. Based on the test experiments, we provide a proof-of-concept of the validity of our claim that our Trust-based RPL protocol provides a comprehensive defence (simulation and testbed) against Blackhole and Selective Forwarding attacks.


2020 ◽  
Vol 11 (1) ◽  
pp. 112-131
Author(s):  
M. Amini ◽  
H. Kalvøy ◽  
Ø.G. Martinsen

AbstractMonitoring a biological tissue as a three dimensional (3D) model is of high importance. Both the measurement technique and the measuring electrode play substantial roles in providing accurate 3D measurements. Bioimpedance spectroscopy has proven to be a noninvasive method providing the possibility of monitoring a 3D construct in a real time manner. On the other hand, advances in electrode fabrication has made it possible to use flexible electrodes with different configurations, which makes 3D measurements possible. However, designing an experimental measurement set-up for monitoring a 3D construct can be costly and time consuming and would require many tissue models. Finite element modeling methods provide a simple alternative for studying the performance of the electrode and the measurement set-up before starting with the experimental measurements. Therefore, in this study we employed the COMSOL Multiphysics finite element modeling method for simulating the effects of changing the electrode configuration on the impedance spectroscopy measurements of a venous segment. For this purpose, the simulations were performed for models with different electrode configurations. The simulation results provided us with the possibility of finding the optimal electrode configuration including the geometry, number and dimensions of the electrodes, which can be later employed in the experimental measurement set-up.


2011 ◽  
Vol 127 ◽  
pp. 439-443
Author(s):  
Hui Wang ◽  
Meng Li

The main research is the dynamics characteristic of the shock excitation part of electro hydraulic control harmonic aging stress elimination devices. Use the system dynamics knowledge to set up a dynamics model of the shock excitation part. Analyze the transfer function of system and then use MATLAB to draw graphics under the condition of different parameters. Through the simulation graphic's analysis, we can obtain the influence of various parameters on system model, so as to provide a reference for the system optimization. MATLAB is abbreviation of Matrix Laboratory, which is used for algorithm development, data visualization, data analysis and numerical calculation of high-level technical computing language and interactive environment. It is useful for us in modeling and simulation.


2018 ◽  
Vol 31 (5) ◽  
pp. 1542-1562 ◽  
Author(s):  
Michael Price ◽  
Charles Harvey ◽  
Mairi Maclean ◽  
David Campbell

PurposeThe purpose of this paper is to answer two main research questions. First, the authors ask the degree to which the UK corporate governance code has changed in response to both systemic perturbations and the subsequent enquiries established to recommend solutions to perceived shortcomings. Second, the authors ask how the solutions proposed in these landmark governance texts might be explained.Design/methodology/approachThe authors take a critical discourse approach to develop and apply a discourse model of corporate governance reform. The authors draw together data on popular, corporate-political and technocratic discourses on corporate governance in the UK and analyse these data using content analysis and the historical discourse approach.FindingsThe UK corporate governance code has changed little despite periodic crises and the enquiries set up to investigate and make recommendation. Institutional stasis, the authors find, is the product of discourse capture and control by elite corporate actors aided by political allies who inhabit the same elite habitus. Review group members draw intertextually on prior technocratic discourse to create new canonical texts that bear the hallmarks of their predecessors. Light touch regulation by corporate insiders thus remains the UK approach.Originality/valueThis is one of the first applications of critical discourse analysis in the accounting literature and the first to have conducted a discursive analysis of corporate governance reports in the UK. The authors present an original model of discourse transitions to explain how systemic challenges are dissipated.


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