scholarly journals Microwave Deicing Efficiency: Study on the Difference between Microwave Frequencies and Road Structure Materials

2018 ◽  
Vol 8 (12) ◽  
pp. 2360 ◽  
Author(s):  
Longting Ding ◽  
Xuancang Wang ◽  
Wengang Zhang ◽  
Shuai Wang ◽  
Jing Zhao ◽  
...  
Keyword(s):  
Finite Element ◽  
Simulation Model ◽  
Microwave Heating ◽  
Asphalt Concrete ◽  
Great Influence ◽  
Microwave Frequency ◽  
Concrete Surface ◽  
Cement Concrete ◽  
Microwave Frequencies ◽  
The Difference

A method of deicing using microwave heating is proposed to make scientific and economical road deicing in a cold area, and to make up for deficiencies in the existing methods for melting snow and ice. This paper proposes to define microwave deicing efficiency as the heating rate of a concrete surface when heated to 0 °C (the efficiency of deicing is equal to the difference divided by heating time, which is between 0 °C and the initial temperature at the junction of ice and concrete). Based on the mechanism of microwave heating and deicing, a method combining the finite element simulation model with indoor experiments was proposed to study the deicing efficiency of microwaves, and the effects of different microwave frequencies and different road structure materials on microwave deicing efficiency were analyzed. The results show that the microwave frequency and road structure materials have a great influence on microwave deicing. For asphalt concrete, the ice melting efficiency of 5.8 GHz is 4.31 times that of 2.45 GHz, but the heating depth is less than that of 2.45 GHz. At 2.45 GHz, the melting efficiency of cement concrete is 3.89 times that of asphalt concrete. At 5.8 GHz, the melting efficiency of cement concrete is 5.23 times that of asphalt concrete. Through the consistency of the simulation and experimental results, the validity of the simulation model based on the finite element theory is verified. The results provide theoretical guidance and a practical basis for future applications of microwave deicing.

Analysis and Simulation on the Influencing Factors of Braking Force for Permanent Magnetic Brake

2013 ◽  
Vol 278-280 ◽  
pp. 278-281 ◽  
Author(s):  
Ming Yao ◽  
Liang Wang
Keyword(s):  
Finite Element ◽  
Simulation Model ◽  
Finite Element Simulation ◽  
Influencing Factors ◽  
Great Influence ◽  
Element Simulation ◽  
Working Principle ◽  
Main Factors ◽  
Braking Force ◽  
Theory Formula

The structure and working principle of permanent magnetic brake were introduced and the main factors of influencing braking ability of the permanent magnetic brake were analyzed with theory formula. By using of software as Ansoft, an finite element simulation model for magnetic brake were built up, and compare simulate value with theoretical one express that they have better consistency. Based on the simulation model, influencing factors of the braking force about permanent magnetic brake were analyzed, and the simulate results express that the height of gap between brake and track has a great influence on the braking force, so it must pay much more attention on brake design.

scholarly journals Predicting Asphalt Pavement Temperature with a Three-Dimensional Finite Element Method

2005 ◽  
Vol 1919 (1) ◽  
pp. 96-110 ◽  
Author(s):  
Manuel J. C. Minhoto ◽  
Jorge C. Pais ◽  
Paulo A. A. Pereira ◽  
Luis G. Picado-Santos
Keyword(s):  
Finite Element ◽  
Simulation Model ◽  
Asphalt Concrete ◽  
Three Dimensional ◽  
Calculated Data ◽  
Thermal Response ◽  
Field Measurements ◽  
Transient Behavior ◽  
Fe Model ◽  
Pavement Temperature

A three-dimensional (3D) finite element (FE) model was developed to calculate the temperature of a pavement located in northeast Portugal. A case study was developed to validate the model. Input data to the model were the hourly values for solar radiation and temperature and mean daily values of wind speed obtained from a meteorological station. The thermal response of a multilayered pavement structure was modeled with a transient thermal analysis for 4 months (December 2003 to April 2004), and the analysis was initiated with the full-depth constant initial temperature obtained from field measurements. During these 4 months, the pavement temperature was measured at a new pavement section, located in IP4 main road, near Bragança, in northern Portugal. At this location, seven thermocouples were installed in the asphalt concrete layers at seven different depths. These pavement data were used to validate this simulation model by a comparison of model calculated data with measured pavement temperatures. The 3D FE analysis proved to be an interesting tool to simulate the transient behavior of asphalt concrete pavements. The suggested simulation model can predict the pavement temperature at different levels of bituminous layers with good accuracy.

scholarly journals SUBSTANTIATION OF APPLICATION OF ANTI-ICE CHEMICAL REAGENTS ON AUTOMOBILE ROADS WITH CEMENT CONCRETE COVERING

2021 ◽  
pp. 112-118
Author(s):  
D. E. Yessentay ◽  
A. K. Kiyalbaev ◽  
S. N. Kiyalbay ◽  
N. V. Borisуuk
Keyword(s):  
Asphalt Concrete ◽  
Concrete Surface ◽  
Strength Properties ◽  
Climatic Conditions ◽  
Eastern Region ◽  
Salt Solutions ◽  
Cement Concrete ◽  
Chemical Reagents ◽  
The Impact ◽  
Snow And Ice

In this paper, we consider the problem associated with the fight against slipperiness on roads with a hard type of road surface. It is known that on cement-concrete surfaces, the length of the braking distance is up to 10 times longer than on a snow roll formed on asphalt-concrete surfaces. This phenomenon is especially dangerous in winter, as a sharp increase in humidity (as a result of warming) significantly reduces the strength properties of cement concrete. Chloride de-icers are highly hygroscopic. Being in the pores of cement concrete, chemical solutions begin to absorb moisture from the atmosphere. In asphalt concrete, such phenomena are practically absent. Moisture, which is located in the pores of cement concrete, on its surface occurs "staining" and peeling. In the article, the authors pay special attention to the climatic conditions of Kazakhstan. The average air temperature of the coldest month on average in the Akmola region is 25-27oC, in the Eastern region-31-36oc, in the North– -26-29 OS, and in the South-3-10 OS. Annual precipitation amounts to 260-300, 340-370, 300-340 and about 150 mm, respectively. the duration of the cold period in the year varies between 6-7, 6-7, 5-6 and 3-4 months. It is climate factors that make it difficult to use chemical reagents as anti-icing materials on roads with a cement-concrete surface. This article discusses the theoretical basis for the destruction of the crystal structure of snow and ice formations from the influence of chemical reagents. They established a natural dependence of the freezing force of snow and ice formations on the impact of various types of salt solutions. Also, laboratory studies have established the effect of the concentration of salt solutions on the loss of strength of cement concrete over time.

scholarly journals Mechanistic Responses of Asphalt Concrete Overlay Over Jointed Plain Concrete Pavement Using Finite Element Method

2020 ◽  
Vol 15 (5) ◽  
pp. 80-93
Author(s):  
Amadou Oury Diallo ◽  
Muhammet Vefa Akpinar
Keyword(s):  
Finite Element ◽  
Portland Cement ◽  
Asphalt Concrete ◽  
Tensile Strain ◽  
Plain Concrete ◽  
Element Model ◽  
Concrete Pavement ◽  
Traffic Load ◽  
Portland Cement Concrete ◽  
Cement Concrete

This study focused on the development of a three-dimensional Finite Element Model of an asphalt concrete overlaid on a jointed plain concrete pavement to assess the mechanical behaviour of the pavement under traffic load. The objective of this study was to determine the influence of different asphalt concrete thickness, asphalt concrete modulus, the interface bond between the asphalt concrete and the Portland cement concrete layer, Portland cement concrete modulus, and joint width on the tensile strain at the bottom of the asphalt overlay. The results showed that changes in the pavement parameters result in a large range of variations on the magnitude of pavement responses. The magnitude of the longitudinal tensile strain at the bottom of the overlay varied between 25 με and 460 με. Asphalt concrete thickness, interface contact condition, and asphalt concrete modulus parameters had the most influence on the pavement responses. The interface bonding condition was significant, regardless of the thickness of the surface layer.

scholarly journals A New Mixed Functional-probabilistic Approach for Finite Element Accuracy

2020 ◽  
Vol 20 (4) ◽  
pp. 799-813
Author(s):  
Joël Chaskalovic ◽  
Franck Assous
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Asymptotic Relation ◽  
Probabilistic Approach ◽  
Random Variable ◽  
High Order ◽  
Relative Accuracy ◽  
The Difference ◽  
New Perspective

AbstractThe aim of this paper is to provide a new perspective on finite element accuracy. Starting from a geometrical reading of the Bramble–Hilbert lemma, we recall the two probabilistic laws we got in previous works that estimate the relative accuracy, considered as a random variable, between two finite elements {P_{k}} and {P_{m}} ({k<m}). Then we analyze the asymptotic relation between these two probabilistic laws when the difference {m-k} goes to infinity. New insights which qualify the relative accuracy in the case of high order finite elements are also obtained.

Finite Element Analysis of Creep Damage Behavior Near the Cavity on Bimaterial Interface

2006 ◽  
Vol 324-325 ◽  
pp. 951-954 ◽  
Author(s):  
Qing Min Yu ◽  
Zhu Feng Yue ◽  
Yong Shou Liu
Keyword(s):  
Finite Element ◽  
Elastic Moduli ◽  
Elastic Stress ◽  
Creep Damage ◽  
Ductile Material ◽  
Bimaterial Interface ◽  
Modulus Ratio ◽  
Element Analysis ◽  
Damage Law ◽  
The Difference

Fracture along an interface between materials plays a major role in failure of material. In this investigation, finite element calculations with Kachanov–Rabotnov damage law were carried out to study the creep damage distribution near the interface cavity in bimaterial specimens. The specimens with central hole were divided into three types. The material parameters of K-R law used in this paper were chosen for a brittle material and ductile material. All calculations were performed under four load cases. Due to the difference between elastic moduli of the bounded materials, the elastic stress field as a function of the Young’s modulus ratio (R=E1/E2) was determined. At the same time, the influence of model type on elastic stress distribution near the cavity was considered. Under the same conditions, the material with larger modulus is subjected to larger stress. The creep damage calculations show that the location of the maximum damage is different for each model. The distributions of creep damage for all three models are dependent on the material properties and load cases.

Stress Analysis of Cement Concrete Pavement under Overweight Loads

2012 ◽  
Vol 446-449 ◽  
pp. 949-953
Author(s):  
Ya Ni Lu ◽  
Tao Li Xiao
Keyword(s):  
Finite Element ◽  
Regression Analysis ◽  
Finite Element Model ◽  
Element Model ◽  
Concrete Pavement ◽  
The Other ◽  
Tension Stress ◽  
Statistical Regression ◽  
Cement Concrete ◽  
Cement Concrete Pavement

Special load has produced serious damage to the concrete pavement because of the great gross weight and heavy axle load, but the present specification has not mentioned this kind of load. On this occasion, Several conditions of critical load are identified through ANSYS finite element model analysis and the formula through statistical regression analysis to the bottom maximum tension stress is drawn up. Which can not only guide the concrete pavement design under the special load but also the result may be referred by the other kinds of engineering.

Numerical Analysis of Branch Mechanical Response to Loading

2019 ◽  
Vol 45 (4) ◽  
Author(s):  
Barbora Vojáčková ◽  
Jan Tippner ◽  
Petr Horáček ◽  
Luděk Praus ◽  
Václav Sebera ◽  
...  
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Mechanical Response ◽  
Mechanical Analysis ◽  
Beam Deflection ◽  
Design System ◽  
Elliptical Cross ◽  
Static Mechanical ◽  
The Difference ◽  
Tree Uprooting

Failure of a tree can be caused by a stem breakage, tree uprooting, or branch failure. While the pulling test is used for assessing the first two cases, there is no device-supported method to assess branch failure. A combination of the optical technique, pulling test, and deflection curve analysis could provide a device-supported tool for this kind of assessment. The aim of the work was to perform a structural analysis of branch response to static mechanical loading. The analyses were carried out by finite element simulations in ANSYS using beam tapered elements of elliptical cross-sections. The numerical analyses were verified by the pulling test combined with a sophisticated optical assessment of deflection evaluation. The Probabilistic Design System was used to find the parameters that influence branch mechanical response to loading considering the use of cantilever beam deflection for stability analysis. The difference in the branch’s deflection between the simulation and the experiment is 0.5% to 26%. The high variability may be explained by the variable modulus of the elasticity of branches. The finite element (FE) sensitivity analysis showed a higher significance of geometry parameters (diameter, length, tapering, elliptical cross-section) than material properties (elastic moduli). The anchorage rotation was found to be significant, implying that this parameter may affect the outcome in mechanical analysis of branch behavior. The branch anchorage can influence the deflection of the whole branch, which should be considered in stability assessment.

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