scholarly journals INITIAL STRESS CORRECTION METHOD FOR THE MODELING OF FOLDED SPACE INFLATABLE STRUCTURES

Aviation ◽  
2014 ◽  
Vol 18 (4) ◽  
pp. 166-173 ◽  
Author(s):  
Yanan Zhan ◽  
Li Yu ◽  
Xue Yang ◽  
Han Cheng
Keyword(s):  
Finite Element ◽  
Initial Stress ◽  
Control Volume ◽  
Technical Problem ◽  
Correction Method ◽  
Numerical Calculations ◽  
Inflatable Structures ◽  
Initial Errors ◽  
Calculation Results ◽  
The Difference

Initial errors and mesh distortions are inevitable in the modelling of folded space inflatable structures. Aimed at this key technical problem, an initial stress correction method based on finite element theory is proposed in this paper. First, initial stress is calculated through the difference of mapping and reference configurations, the former with initial errors and the later without. Then the initial stress is imposed on the mapping configuration to correct initial errors. Through the correction, the accuracy of the inflation deployment numerical calculation is greatly improved. In order to validate the reliability of this correction method, a typical space inflatable structure-inflatable tube is studied as an example. First of all, the finite element models of both Z-folded and rolled tubes are established with the initial stress correction method. Then the inflation deployment numerical calculations of the folded tubes are carried out applying the segmented inflatable control volume method. Through comparative analysis of the calculation results with and without a correction, the method proposed in this paper is proved to be feasible and accurate. The correction method is a complement to the modelling of folded space inflatable structures and it has a great significance for the improvement of the accuracy of the inflation deployment numerical calculations of space inflatable structures.

Thermal Stresses Simulation Analysis of Concrete Box Water Bridge under the Solar Radiation

2011 ◽  
Vol 255-260 ◽  
pp. 952-956
Author(s):  
Jian Ping Sun ◽  
Jian Ping Chen ◽  
Gang Li
Keyword(s):  
Finite Element ◽  
Tensile Strength ◽  
Solar Radiation ◽  
Thermal Stresses ◽  
Simulation Analysis ◽  
Water Bridge ◽  
Finite Element Software ◽  
Steel Bar ◽  
Calculation Results ◽  
The Difference

The reasons why the producing of the difference in temperature distributing and thermal stresses of box aqueduct under solar radiation are analyzed. The difference in temperature distributing and thermal stresses are effectively simulated by the finite element software ANSYS.The calculation results indicate that concrete box aqueduct body inter-surface whatever along the longitudinal and transverse will produce considerable thermal stresses under solar radiation, and its value has exceeded the design of concrete tensile strength. Therefore, the thermal stresses under the solar radiation must be considered in the design of box aqueduct body structural. We should appropriately configure temperature reinforcing steel bar.

scholarly journals Sequential assimilation of multi-mission dynamical topography into a global finite-element ocean model

2008 ◽  
Vol 5 (2) ◽  
pp. 255-279
Author(s):  
S. Skachko ◽  
S. Danilov ◽  
T. Janjić ◽  
J. Schröter ◽  
D. Sidorenko
Keyword(s):  
Finite Element ◽  
Ocean Circulation ◽  
Complex Analysis ◽  
Correction Method ◽  
Ocean Model ◽  
Accurate Estimation ◽  
Observation Data ◽  
Dynamic Topography ◽  
The Mean ◽  
The Difference

Abstract. This study focuses on an accurate estimation of ocean circulation via assimilation of satellite measurements of ocean dynamical topography into the global finite-element ocean model (FEOM). The dynamical topography data are derived from a complex analysis of multi-mission altimetry data combined with a referenced earth geoid. The assimilation is split into two parts. First, the mean dynamic topography is adjusted. To this end an adiabatic pressure correction method is used which reduces model divergence from the real evolution. Second, a sequential assimilation technique is applied to improve the representation of thermodynamical processes by assimilating the time varying dynamic topography. A method is used according to which the temperature and salinity are updated following the vertical structure of the first baroclinic mode. It is shown that the method leads to a partially successful assimilation approach reducing the rms difference between the model and data from 16 cm to 2 cm. This improvement of the mean state is accompanied by significant improvement of temporal variability in our analysis. However, it remains suboptimal, showing a tendency in the forecast phase of returning toward a free run without data assimilation. Both the mean difference and standard deviation of the difference between the forecast and observation data are reduced as the result of assimilation.

Analysis of Continuous Girder Bridge Based on Different Codes

2013 ◽  
Vol 361-363 ◽  
pp. 1311-1314
Author(s):  
Meng Ying Liu ◽  
Bang Zhe Liu
Keyword(s):  
Finite Element ◽  
Comparative Analysis ◽  
Girder Bridges ◽  
Calculation Results ◽  
Continuous Girder Bridge ◽  
The Difference ◽  
Girder Bridge

As the object to continuous girder bridges of movable formwork construction,for the same real bridge according to the new code and old code respectively establish finite element mode and for the corresponding calculation and checked, through the comparative analysis about construct materials, calculation conditions and the calculation results, etc,to discuss the difference of the design results between the new standard and the old standard, in order to accumulated useful experience about designing new bridge and reinforcing and reforming old bridge.

Elastic Stress Distribution in Layered Spherical Shells With Gaps Caused by Internal Pressure

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Shugen Xu ◽  
Chao Chen
Keyword(s):  
Finite Element ◽  
Spherical Shell ◽  
Elastic Stress ◽  
Outer Wall ◽  
Wall Surface ◽  
The Finite Element Method ◽  
Spherical Shells ◽  
Calculation Results ◽  
The Difference ◽  
Stress Discontinuity

An interlayer gap is inevitable in layered spherical shells. Therefore, the classic formulae for the monobloc spherical shell can no longer be used. In this paper, the formulae for the elastic stress calculation of layered spherical shells were proposed and the difference between the proposed formulae and ASME formulae was clarified. Interlayer gaps induce stress redistribution and stress discontinuity in the layered spherical shell. The hoop stress in the inner wall surface becomes higher than that in the monobloc spherical shell, and the stress in the outer wall surface is lower. Calculation results obtained from the proposed formulae were compared to those obtained by the finite element method (FEM) and ASME formulae. It was shown that the results from the proposed formulae are in accordance with finite element results.

scholarly journals Sequential assimilation of multi-mission dynamical topography into a global finite-element ocean model

Ocean Science ◽  
2008 ◽  
Vol 4 (4) ◽  
pp. 307-318 ◽  
Author(s):  
S. Skachko ◽  
S. Danilov ◽  
T. Janjić ◽  
J. Schröter ◽  
D. Sidorenko ◽  
...  
Keyword(s):  
Finite Element ◽  
Ocean Circulation ◽  
Complex Analysis ◽  
Correction Method ◽  
Ocean Model ◽  
Accurate Estimation ◽  
Observation Data ◽  
Dynamic Topography ◽  
The Mean ◽  
The Difference

Abstract. This study focuses on an accurate estimation of ocean circulation via assimilation of satellite measurements of ocean dynamical topography into the global finite-element ocean model (FEOM). The dynamical topography data are derived from a complex analysis of multi-mission altimetry data combined with a referenced earth geoid. The assimilation is split into two parts. First, the mean dynamic topography is adjusted. To this end an adiabatic pressure correction method is used which reduces model divergence from the real evolution. Second, a sequential assimilation technique is applied to improve the representation of thermodynamical processes by assimilating the time varying dynamic topography. A method is used according to which the temperature and salinity are updated following the vertical structure of the first baroclinic mode. It is shown that the method leads to a partially successful assimilation approach reducing the rms difference between the model and data from 16 cm to 2 cm. This improvement of the mean state is accompanied by significant improvement of temporal variability in our analysis. However, it remains suboptimal, showing a tendency in the forecast phase of returning toward a free run without data assimilation. Both the mean difference and standard deviation of the difference between the forecast and observation data are reduced as the result of assimilation.

Analysis the same Continuous Girder Bridge Based on Different Construction Methods

2013 ◽  
Vol 361-363 ◽  
pp. 1319-1324
Author(s):  
Meng Ying Liu ◽  
Yue Xu
Keyword(s):  
Finite Element ◽  
Prestressed Concrete ◽  
Action Effects ◽  
Construction Methods ◽  
Calculation Results ◽  
Continuous Girder Bridge ◽  
The Difference ◽  
Girder Bridge

As the object to a prestressed concrete continuous girder bridge, which is an actual bridge, finite element modes were established respectively for the same actual bridge in different construction methods. The calculation results were analyzed comparatively and then the difference of the design results between the two construction methods was discussed in the gravity of structures, combination for action effects and the reinforcement bars, in order to accumulate useful experience in designing bridges.

Numerical implementation of finite-element method of control volume using irregular mesh

2010 ◽  
Vol 7 ◽  
pp. 98-108
Author(s):  
Yu.A. Gafarova
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Delaunay Triangulation ◽  
Complex Geometry ◽  
Control Volume ◽  
Test Case ◽  
The Finite Element Method ◽  
Irregular Mesh ◽  
Discrete Analogues ◽  
Element Method

To solve problems with complex geometry it is considered the possibility of application of irregular mesh and the use of various numerical methods using them. Discrete analogues of the Beltrami-Mitchell equations are obtained by the control volume method using the rectangular grid and the finite element method of control volume using the Delaunay triangulation. The efficiency of using the Delaunay triangulation, Voronoi diagrams and the finite element method of control volume in a test case is demonstrated.

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.

scholarly journals Comparison of Building Simulation Methods for Modeling Apartment Balconies

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3955
Author(s):  
Yonghan Ahn ◽  
Hanbyeol Jang ◽  
Junghyon Mun
Keyword(s):  
Heat Transfer ◽  
Air Temperature ◽  
Parameter Analysis ◽  
Interior Space ◽  
Heating And Cooling ◽  
Significant Difference ◽  
Calculation Results ◽  
Infiltration Parameter ◽  
The Difference ◽  
Heating And Cooling Load

The purpose of this study is to compare the load calculation results by a model using the air changes per hour (ACH) method and a model using an airflow network (AFN) and to ascertain what causes the difference between the two models. In the basic case study, the difference in the heat transfer distribution of the model in the interior space was investigated. The most significant difference between the two models is the heat transfer that results from infiltration. Parameter analysis was performed to investigate the relationship between the difference and the environmental variables. The result shows that the greater the difference is between the air temperature inside the balcony and the outdoor air temperature, and the greater the air flows from the balcony to the residential area, and the greater the heating and cooling load difference occurs. The analysis using the actual weather files of five domestic cities in South Korea rather than a virtual case shows that the differences are not so obvious when the wind blows at a constant speed throughout the year, but are dominant when the wind does not blow during the night and is stronger alongside the occurrence of sunlight during the day.

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