scholarly journals Research of Thermal Effect of Cable-Stayed Bridge with a Separated Side-Box Steel-Concrete Composite Girder under Solar Radiation

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Han-hao Zhang ◽  
Pei-zhi Wang ◽  
Shuanhai He ◽  
Yuan Li ◽  
Ke-fan Chen ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Thermal Effect ◽  
Temperature Stress ◽  
Thermal Field ◽  
Element Model ◽  
Beam Element ◽  
Maximum Temperature ◽  
Cable Stayed Bridge ◽  
Composite Girder ◽  
Mixed Element

At present, there are few studies on the thermal effect of solar radiation on a separated double-sided box steel-concrete composite girder cable-stayed bridge. In this paper, the beam element and mixed element models are combined with the theory of transient heat transfer analysis and meteorology; this approach is adopted to carry out a thermodynamic analysis of a related bridge project. The calculation results of the thermal field and structural thermodynamic analysis of bridge sections show that, in terms of a separated double-sided box steel-concrete composite girder cable-stayed bridge, the thermal field distributions of the main girder and the pylons are extremely complex under conditions of solar radiation. Therefore, the real thermal field cannot be accurately described as a one-dimensional temperature gradient. The traditional beam element model cannot accurately simulate the temperature effect, and it will underestimate its thermal effect. The calculated temperature stress values of the mixed element model are quite different from those of the of beam element model. The mixed element model can precisely reflect the local thermal effect of each component in this system under solar radiation. Compared with the calculation results of the beam element model, the maximum temperature stress of the bridge deck in each section of the main girder is generally 20% larger; the maximum temperature stress levels of the steel-beam top and bottom plates are 14.7 MPa and 15.9 MPa larger, respectively. The maximum shear stress of the steel-concrete interface is 0.2 MPa larger. The research results of the temperature effect calculated by the mixed element have an important guiding significance for the design and maintenance of bridges.

scholarly journals A study of improving thermal environment of external louver through establishment of test bed

2018 ◽  
Vol 7 (3.3) ◽  
pp. 373
Author(s):  
Sun Pil Kwon ◽  
Jae Jun Jung ◽  
Byoung Jo Jung
Keyword(s):  
Statistical Analysis ◽  
Solar Radiation ◽  
Thermal Effect ◽  
Thermal Load ◽  
Thermal Environment ◽  
Direct Solar Radiation ◽  
Maximum Temperature ◽  
Test Bed ◽  
Solar Insolation ◽  
Maximum Temperature Difference

Background/Objectives: To improve a thermal load by increasing internal thermal effect of a building from direct solar radiation through an increase of glass windows.Methods/Statistical analysis: Through the establishment of test beds of the same size, the data of temperature, humidity, solar insolation and PMV of each test bed with or without external louver are acquired to analyze thermal environmental with the simulation.Findings: For the analysis of thermal environment, the amount of energy consumption has been analyzed through the simulation and the data of temperature, humidity, solar insolation and PMV have been acquired for the analysis. With the simulation, about 20% energy saving has been confirmed and the daily averages of temperature and humidity between 8AM to 7PM have been calculated to calculate the maximum temperature difference to be 9.4℃. The solar insolation between 9AM and 7PM was 300W/m2 or below.Improvements/Applications: The improvement of thermal effect with an external louver has been confirmed. It may be applied to the louver system to improve building thermal environment, awning to control direct solar radiation, blind to improve uniformity of illumination intensity toward building during daytime, external blind and ceiling louver system. 

scholarly journals Thermal Effect of Single Loop Shield on High-Voltage Cable Line Capacity

2021 ◽  
Author(s):  
Oleksandr Tkachenko ◽  
◽  
Vladimir Grinchenko ◽  
Pavel Dobrodeyev ◽  
◽  
...  
Keyword(s):  
Thermal Effect ◽  
High Voltage ◽  
Thermal Field ◽  
Magnetic Coupling ◽  
Maximum Temperature ◽  
Thermal Resistivity ◽  
Power Cables ◽  
Cable Line ◽  
Single Loop ◽  
Short Section

The paper deals with a single-loop shield with an asymmetric magnetic coupling used for a magnetic field mitigation of a high-voltage three-phase cable line. The goal is to evaluate a thermal effect of this shield on a cable line capacity. To calculate the flat cable line capacity in the nonshielded case, we use a standard IEC 60287. To achieve the goal we carry out a numerical simulation of the thermal field when the shield is installed. Wherein, we deal with two specific sections. One is a long section with the shield being distant from the cable line. The other is a relatively short section where the shield is located near the power cables. The thermal field is applied for a long section in a two-dimensional formulation, and a three-dimensional formulation is used for the short section. Hence, we have obtained the dependences of the maximum temperature of the power cables on parameters of the shield and its location height above the cable line. The most significant allowable cross-sections of the shield cable and their location height have been determined, when the thermal effect of the shield does not decrease the cable line capacity. These results have ensured the maximum cable line capacity while shielding. The shield temperature is shown to exceed the allowable level in the short section. To reduce it the thermal backfill has been used. We recommend the values of its thermal resistivity to be used for different parameters of the single-loop shield.

Finite element bending analysis of symmetric and non-symmetric functionally graded sandwich beams using a novel parabolic shear deformation theory

2021 ◽  
pp. 146442072110050
Author(s):  
Mohamed-Ouejdi Belarbi ◽  
Abdelhak Khechai ◽  
Aicha Bessaim ◽  
Mohammed-Sid-Ahmed Houari ◽  
Aman Garg ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Shear Deformation ◽  
Transverse Shear ◽  
Deformation Theory ◽  
Shear Deformation Theory ◽  
Element Model ◽  
Beam Element ◽  
Functionally Graded ◽  
Sandwich Beams

In this paper, the bending behavior of functionally graded single-layered, symmetric and non-symmetric sandwich beams is investigated according to a new higher order shear deformation theory. Based on this theory, a novel parabolic shear deformation function is developed and applied to investigate the bending response of sandwich beams with homogeneous hardcore and softcore. The present theory provides an accurate parabolic distribution of transverse shear stress across the thickness and satisfies the zero traction boundary conditions on the top and bottom surfaces of the functionally graded sandwich beam without using any shear correction factors. The governing equations derived herein are solved by employing the finite element method using a two-node beam element, developed for this purpose. The material properties of functionally graded sandwich beams are graded through the thickness according to the power-law distribution. The predictive capability of the proposed finite element model is demonstrated through illustrative examples. Four types of beam support, i.e. simply-simply, clamped-free, clamped–clamped, and clamped-simply, are used to study how the beam deflection and both axial and transverse shear stresses are affected by the variation of volume fraction index and beam length-to-height ratio. Results of the numerical analysis have been reported and compared with those available in the open literature to evaluate the accuracy and robustness of the proposed finite element model. The comparisons with other higher order shear deformation theories verify that the proposed beam element is accurate, presents fast rate of convergence to the reference results and it is also valid for both thin and thick functionally graded sandwich beams. Further, some new results are reported in the current study, which will serve as a benchmark for future research.

Thermal effect of the cable-stayed bridge tower

2003 ◽  
Vol 8 (4) ◽  
pp. 1121-1125 ◽  
Author(s):  
Zhang Hai-long ◽  
Li Jun ◽  
Liu Changguo ◽  
Jiang Tian-hua ◽  
Wei jun
Keyword(s):  
Thermal Effect ◽  
Cable Stayed Bridge ◽  
Bridge Tower

Contrastive Study on Finite Element Models of High-Strength Pipelines Crossing Active Faults

2016 ◽  
Vol 850 ◽  
pp. 957-964
Author(s):  
Wei Zheng ◽  
Hong Zhang ◽  
Xiao Ben Liu ◽  
Le Cai Liang ◽  
Yin Shan Han
Keyword(s):  
Finite Element ◽  
Design Method ◽  
Active Faults ◽  
Shell Element ◽  
High Strength ◽  
Element Model ◽  
Beam Element ◽  
Finite Element Models ◽  
Fixed Boundary ◽  
Equivalent Boundary

There is a potential for major damage to the pipelines crossing faults, therefore the strain-based design method is essential for the design of buried pipelines. Finite element models based on soil springs which are able to accurately predict pipelines’ responses to such faulting are recommended by some international guidelines. In this paper, a comparative analysis was carried out among four widely used models (beam element model; shell element model with fixed boundary; shell element model with beam coupled; shell element model with equivalent boundary) in two aspects: differences of results and the efficiency of calculation. The results show that the maximum and minimum strains of models coincided with each other under allowable strain and the calculation efficiency of beam element model was the highest. Besides, the shell element model with beam coupled or equivalent boundary provided the reasonable results and the calculation efficiency of them were higher than the one with fixed boundary. In addition, shell element model with beam coupled had a broader applicability.

Ecological Niche Modeling Predicting the Potential Distribution of African Horse Sickness Virus from 2020 - 2060

2021 ◽  
Author(s):  
Ayalew Assefa ◽  
Abebe Tibebu ◽  
Amare Bihon ◽  
Alemu Dagnachew ◽  
Yimer Muktar
Keyword(s):  
Solar Radiation ◽  
Ecological Niche ◽  
Annual Precipitation ◽  
Maximum Temperature ◽  
Mean Annual Precipitation ◽  
African Horse Sickness ◽  
Diurnal Range ◽  
Annual Minimum Temperature ◽  
Precipitation Seasonality ◽  
Vector Borne

Abstract African horse sickness is a vector-borne, non-contagious and highly infectious disease of equines caused by African Horse Sickness viruses (AHSv) that mainly affect horses. The occurrence of the disease causes huge economic impacts because of its fatality rate is high, trade ban and disease control costs. In planning of vectors and vector borne diseases, the application of Ecological niche models (ENM) used an enormous contribution in exactly delineating the suitable habitats of the vector. We developed an ENM with the objective of delineating the global suitability of AHSv outbreaks retrospective based on data records from 2005–2019. The model was developed in R software program using Biomod2 package with an Ensemble modeling technique. Predictive environmental variables like mean diurnal range, mean precipitation of driest month(mm), precipitation seasonality (cv), mean annual maximum temperature (oc), mean annual minimum temperature (oc) mean precipitation of warmest quarter(mm), mean precipitation of coldest quarter (mm) mean annual precipitation (mm), solar radiation (kj /day), elevation/altitude (m), wind speed (m/s) were used to develop the model. From these variables, solar radiation, mean maximum temperature, average annual precipitation, altitude and precipitation seasonality contributed 36.83%, 17.1%, 14.34%, 7.61%, and 6.4%, respectively. The model depicted the sub-Sahara African continent as the most suitable area for the virus. Mainly Senegal, Burkina Faso, Niger, Nigeria, Ethiopia, Sudan, Somalia, South Africa, Zimbabwe, Madagascar and Malawi are African countries identified as highly suitable countries for the virus. Besides, OIE-listed disease-free countries like India, Australia, Brazil, Paraguay and Bolivia have been found suitable for the virusThis model can be used as an epidemiological tool in planning control and surveillance of diseases nationally or internationally.

Research on the anti-cracking ability of large composite girder cable- stayed bridge

2019 ◽  
Author(s):  
Yuhao Huang ◽  
Liu Chao ◽  
Xu Dong
Keyword(s):  
Principal Stress ◽  
Bridge Deck ◽  
Design Method ◽  
Concrete Bridge ◽  
Cable Stayed Bridge ◽  
Composite Girder ◽  
Concrete Bridge Deck ◽  
Bottom Slab ◽  
First Time ◽  
Bridge Tower

<p>Recently, composite girder cable-stayed bridge is widely used in the world. Since the existing design method takes less focus on the principal stress of the top and bottom slab, the cracking problem of the concrete bridge deck has not been solved perfectly yet. Based on the spatial grid model, this paper takes Guan He Bridge in Jiangsu province as an example to analyze this kind of structure. Monitoring the principal stress of the concrete bridge deck is proposed for the first time to study the effect of diagonal crack. The principal stress of the concrete deck in the middle span, the quartile span, one-eighth of the span, the side span, the bridge tower, and the auxiliary pier are observed respectively. Comparing the theoretical values with the measured value, the results show that the actual stress state of the whole concrete bridge deck during construction is in accordance with the theoretical calculation. For composite girder cable-stayed bridge, the concrete bridge deck is prone to crack, so it is very significant to control the quality in the construction stage, which can provide a guarantee for the safety and durability of the structure.</p>

Calculating Mechanics Characteristics of Single-Walled Carbon Nanotube Materials by Finite Element Method

2017 ◽  
Vol 730 ◽  
pp. 548-553
Author(s):  
Jing Ge ◽  
Hao Jiang ◽  
Zhen Yu Sun ◽  
Guo Jun Yu ◽  
Bo Su ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Radial Direction ◽  
Element Model ◽  
Beam Element ◽  
Beam Position ◽  
Single Walled Carbon ◽  
Finite Element Software ◽  
Calculation Results ◽  
The Moment

In this paper, we establish the mechanical property analysis of Single-walled Carbon Nanotubes (SWCNTs) modified beam element model based on the molecular structural mechanics method. Then we study the mechanical properties of their radial direction characteristics using the finite element software Abaqus. The model simulated the different bending stiffness with rectangular section beam elements C-C chemical force field. When the graphene curled into arbitrary chirality of SWCNTs spatial structure, the adjacent beam position will change the moment of inertia of the section of the beam. Compared with the original beam element model and the calculation results, we found that the established model largely reduced the overestimate of the original model of mechanical properties on the radial direction of the SWCNTs. At the same time, compared with other methods available in the literature results and the experimental data, the results can be in good agreement.

Dynamic Characteristics of a Long-Span Cable-Stayed Bridge

2011 ◽  
Vol 480-481 ◽  
pp. 1496-1501
Author(s):  
Liu Hui
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Iteration Method ◽  
Natural Frequencies ◽  
Element Model ◽  
Vibration Modes ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Subspace Iteration ◽  
Floating System

In order to study the dynamic characteristics of a super-long-span cable-stayed bridge which is semi-floating system, the spatial finite element model of this cable-stayed bridge was established in ANSYS based on the finite element theory.Modal solution was conducted using subspace iteration method, and natural frequencies and vibration modes were obtained.The dynamic characteristics of this super-long-span cable-stayed bridge were then analyzed.Results showed that the super-long-span cable-stayed bridge of semi-floating system has long basic cycle, low natural frequencies, dense modes and intercoupling vibration modes.

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