FINITE ELEMENT MODELING OF THERMAL LOADING ON STEEL BOX GIRDERS

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Marco Diversi ◽  
Hans De Backer
Keyword(s):  
Finite Element ◽  
Thermal Loading ◽  
Thermal Gradients ◽  
Detailed Calculation ◽  
The Sun ◽  
Thermal Loads ◽  
Surface Layers ◽  
Box Girders ◽  
One Year ◽  
Hourly Basis

Thermal loads are not often considered during the design of steel box girders, but their influence can be quite important. When the thermal gradient within the steel box girders reaches considerable values, a number of other effects are influenced. High thermal gradients will reduce the cohesion of waterproofing layers and surface layers. Therefore, the quantification of the thermal loads acting on the system becomes essential. This is primarily done using detailed finite element models of steel box girders. Modelling all the thermal fluxes within this system, including solar radiation, radiation with the environment, mutual radiation, convective airflow, etc. it becomes possible to study the temperature variations on the bridge structure. The thermal loading is based on the actual revolution of the sun, while the bounds and the orientation angles are the result of a detailed calculation of the position of the sun. The same is true for the respective fluxes. All of these variations are studied along a one year period and this on hourly basis.

Beam finite element for thin-walled box girders considering shear lag and shear deformation effects

2021 ◽  
Vol 233 ◽  
pp. 111867
Author(s):  
Xiayuan Li ◽  
Shui Wan ◽  
Yuanhai Zhang ◽  
Maoding Zhou ◽  
Yilung Mo
Keyword(s):  
Finite Element ◽  
Shear Deformation ◽  
Shear Lag ◽  
Box Girders ◽  
Thin Walled

Natural frequency analysis of a functionally graded rotor-bearing system with a slant crack subjected to thermal gradients

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Arnab Bose ◽  
Prabhakar Sathujoda ◽  
Giacomo Canale
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Power Law ◽  
Beam Theory ◽  
Functionally Graded ◽  
Thermal Gradients ◽  
Element Analysis ◽  
Rotor Bearing ◽  
Natural Frequency Analysis ◽  
Bearing System

Abstract The present work aims to analyze the natural and whirl frequencies of a slant-cracked functionally graded rotor-bearing system using finite element analysis for the flexural vibrations. The functionally graded shaft is modelled using two nodded beam elements formulated using the Timoshenko beam theory. The flexibility matrix of a slant-cracked functionally graded shaft element has been derived using fracture mechanics concepts, which is further used to develop the stiffness matrix of a cracked element. Material properties are temperature and position-dependent and graded in a radial direction following power-law gradation. A Python code has been developed to carry out the complete finite element analysis to determine the Eigenvalues and Eigenvectors of a slant-cracked rotor subjected to different thermal gradients. The analysis investigates and further reveals significant effect of the power-law index and thermal gradients on the local flexibility coefficients of slant-cracked element and whirl natural frequencies of the cracked functionally graded rotor system.

scholarly journals Modeling of the buckstay system of membrane-walls in watertube boiler construction

2014 ◽  
Vol 18 (suppl.1) ◽  
pp. 59-72 ◽  
Author(s):  
Hasan Nagiar ◽  
Tasko Maneski ◽  
Vesna Milosevic-Mitic ◽  
Branka Gacesa ◽  
Nina Andjelic
Keyword(s):  
Finite Element ◽  
Orthotropic Plate ◽  
Global Model ◽  
Local Model ◽  
Thermal Loads ◽  
Water Tube ◽  
Bending Load ◽  
Specific Geometry ◽  
Structural Parts ◽  
Help Model

Membrane walls are very important structural parts of water-tube boiler construction. Based on their specific geometry, one special type of finite element was defined to help model the global boiler construction. That is the element of reduced orthotropic plate with two thicknesses and two elasticity matrixes, for membrane and bending load separately. A global model of the boiler construction showed that the high value of stress is concentrated in plates of the buckstay system in boiler corners. Validation of the new finite element was done on the local model of the part of membrane wall and buckstay. A very precise model of tubes and flanges was compared to the model formed on the element of a reduced orthotropic plate. Pressure and thermal loads were discussed. Obtained results indicated that the defined finite element was quite favorable in the design and reconstruction of the boiler substructures such as a buckstay system.

Elastic Design Methods for Perforated Plates

1978 ◽  
Vol 100 (2) ◽  
pp. 356-362 ◽  
Author(s):  
J. S. Porowski ◽  
W. J. O’Donnell
Keyword(s):  
Finite Element ◽  
Thermal Loading ◽  
Solid Material ◽  
Perforated Plates ◽  
Finite Element Stress Analysis ◽  
Effective Elastic Constants ◽  
New Methods ◽  
Circular Holes ◽  
Elastic Design ◽  
Generalized Plane Strain

Methods for performing finite element stress analysis of perforated plates under pressure and complex thermal loading conditions are described. The concept of the equivalent solid material of anisotropic properties is employed to define the elasticity matrices to be used for axisymmetric analysis of plates containing triangular and square patterns of circular holes. Generalized plane strain effective elastic constants are used for better approximation of the overall plate behavior. New methods and curves for obtaining local ligament stresses from the nominal stresses in the equivalent solid material are given.

Analysis of Deformation for PC Thin-Wall Box Girders Exposed to Fire

2011 ◽  
Vol 368-373 ◽  
pp. 930-933
Author(s):  
Wei Hou ◽  
Shuan Hai He ◽  
Cui Juan Wang ◽  
Gang Zhang
Keyword(s):  
Finite Element ◽  
Thin Wall ◽  
Fire Load ◽  
Box Girders ◽  
Conduction Model ◽  
Load Model ◽  
Deformation Problem ◽  
Finite Element Procedure ◽  
Thin Walled

Being aimed to deformation problem of pre-stressed concrete thin-walled multi-room box girders exposed to co-action of fire and load, on the basis of enthalpy conduction model and thermo-mechanics parameters, the finite element procedure was applied to analyze the deformation of three spans pre-stressed concrete thin-walled multi-room box girders exposed to co-action of fire and load. In conclusion, the deflection is obvious under action of the variation width and fire load model.

An Experimental and Numerical Methodology to Investigate Crack Growth in a 304L Austenitic Stainless Steel Pipe Under Thermal Fatigue

2010 ◽  
Author(s):  
Pauline Bouin ◽  
Antoine Fissolo ◽  
Ce´dric Gourdin
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Crack Growth ◽  
Thermal Fatigue ◽  
Thermal Loading ◽  
Steel Pipe ◽  
Design Stage ◽  
Inner Surface ◽  
Stainless Steel Pipe

This paper covers work carried out by the French Atomic Energy Commission (CEA) to investigate on mechanisms leading to cracking of piping as a result of thermal loading existing in flow mixing zones. The main purpose of this work is to analyse, with a new experiment and its numerical interpretation, and to understand the mechanism of propagation of cracks in such components. To address this issue, a new specimen has been developed on the basis of the Fat3D experiment. This thermal fatigue test consists in heating a 304L steel pre-cracked tube while cyclically injecting ambient water onto its inner surface. The tube is regularly removed from the furnace for a crack characterisation. Finally, the crack growth is evaluated from the crack length differences between two stops. In parallel, a finite element analysis is developed using the finite element Cast3M code. A pipe with a semi-elliptical crack on its inner surface is modelled. A cyclic thermal loading is imposed on the tube. This loading is in agreement with experimental data. The crack propagates through the thickness. A prediction of the velocity of the crack is finally assessed using a Paris’ law type criteria. Finally, this combined experimental and numerical work on 304L austenitic stainless steel pipes will enable to improve existing methods to accurately predict the crack growth under cyclic thermal loadings in austenitic stainless steel pipe at the design stage.

Finite Element Calculation and Pushing Construction Analysis on the Superstructure of Beijiang Auxiliary Channel Bridge

2012 ◽  
Vol 204-208 ◽  
pp. 2167-2171
Author(s):  
Yu Lan Wang ◽  
Guo Dong Zheng
Keyword(s):  
Finite Element ◽  
Reference Value ◽  
Construction Process ◽  
Element Calculation ◽  
Box Girders ◽  
Element Analysis ◽  
Shrinkage And Creep ◽  
Load Effects ◽  
Live Loads ◽  
The Right

Finite element analysis and calculation are held on the superstructure of the auxiliary channel bridge at the right branching of Beijiang Bridge for a short condition and the service phase. The theoretical launching force is calculated and amended in construction. The results show that when considering load effects such as the dead loads of box girders, the live loads of decks and the pre-stressed secondary forces, the eccentric stress state will appear on the webs, and the steel stress produced by shrinkage and creep of concrete can not be ignored. So the launching force must be amended during the construction process. These conclusions have a certain reference value on the bridge design and construction.

Experimental Characterization and Finite Element Modeling of Film Capacitors for Automotive Applications

2016 ◽  
Author(s):  
D. Croccolo ◽  
T. M. Brugo ◽  
M. De Agostinis ◽  
S. Fini ◽  
G. Olmi
Keyword(s):  
Finite Element ◽  
Mechanical Response ◽  
High Reliability ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Life Time ◽  
Element Model ◽  
Image Correlation ◽  
Thermal Loads ◽  
Mechanical Shock

As electronics keeps on its trend towards miniaturization, increased functionality and connectivity, the need for improved reliability capacitors is growing rapidly in several industrial compartments, such as automotive, medical, aerospace and military. Particularly, recent developments of the automotive compartment, mostly due to changes in standards and regulations, are challenging the capabilities of capacitors in general, and especially film capacitors. Among the required features for a modern capacitor are the following: (i) high reliability under mechanical shock, (ii) wide working temperature range, (iii) high insulation resistance, (iv) small dimensions, (v) long expected life time and (vi) high peak withstanding voltage. This work aims at analyzing the key features that characterize the mechanical response of the capacitor towards temperature changes. Firstly, all the key components of the capacitor have been characterized, in terms of strength and stiffness, as a function of temperature. These objectives have been accomplished by means of several strain analysis methods, such as strain gauges, digital image correlation (DIC) or dynamic mechanical analysis (DMA). All the materials used to manufacture the capacitor, have been characterized, at least, with respect to their Young’s modulus and Poisson’s ratio. Then, a three-dimensional finite element model of the whole capacitor has been set up using the ANSYS code. Based on all the previously collected rehological data, the numerical model allowed to simulate the response in terms of stress and strain of each of the capacitor components when a steady state thermal load is applied. Due to noticeable differences between the thermal expansion coefficients of the capacitor components, stresses and strains build up, especially at the interface between different components, when thermal loads are applied to the assembly. Therefore, the final aim of these numerical analyses is to allow the design engineer to define structural optimization strategies, aimed at reducing the mechanical stresses on the capacitor components when thermal loads are applied.

Clamp Load Decay Due to Material Creep of Lightweight-Material Joints Under Cyclic Temperature

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Sayed A. Nassar ◽  
Amir Kazemi
Keyword(s):  
Finite Element ◽  
Temperature Profile ◽  
Thermal Loading ◽  
Substrate Material ◽  
Valuable Insight ◽  
Substrate Thickness ◽  
Element Analysis ◽  
Fea Model ◽  
Cyclic Temperature ◽  
Material Creep

Experimental and finite element techniques are used for investigating the effect of cyclic thermal loading on the clamp load decay in preloaded single-lap bolted joints that are made of multimaterial lightweight alloys. Substrate material combinations include aluminum, magnesium, and steel, with various coupon thicknesses. The range of cyclic temperature profile varies between −20 °C and +150 °C in a computer-controlled environmental chamber for generating the desired cyclic temperature profile and durations. Real time clamp load data are recorded using strain gage-based, high-temperature, load cells. Clamp load decay is investigated for various combinations of joint materials, initial preload level, and substrate thickness. Thermal and material creep finite element analysis (FEA) is performed using temperature-dependent mechanical properties. The FEA model and results provided a valuable insight into the experimental results regarding the vulnerability of some lightweight materials to significant material creep at higher temperatures.

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