A Nonlinear Generalized Thermoelasticity Model of Temperature-Dependent Materials Using Finite Element Method

2012 ◽  
Vol 33 (7) ◽  
pp. 1302-1313 ◽  
Author(s):  
Ibrahim A. Abbas ◽  
Hamdy M. Youssef
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Generalized Thermoelasticity ◽  
Temperature Dependent ◽  
Element Method

scholarly journals Prediction of Characteristic Length and Fracture Toughness in Ductile-Brittle Transition

2008 ◽  
Author(s):  
Z. X. Wang ◽  
H. M. Li ◽  
Y. J. Chao ◽  
P. S. Lam
Keyword(s):  
Finite Element Method ◽  
Fracture Toughness ◽  
Finite Element ◽  
Characteristic Length ◽  
Crack Tip ◽  
Critical Distance ◽  
Transition Regime ◽  
Temperature Dependent ◽  
Brittle Transition ◽  
Element Method

Finite element method was used to analyze the three-point bend experimental data of A533B-1 pressure vessel steel obtained by Sherry, Lidbury, and Beardsmore [1] from −160 to −45 °C within the ductile-brittle transition regime. As many researchers have shown, the failure stress (σf) of the material could be approximated as a constant. The characteristic length, or the critical distance (rc) from the crack tip, at which σf is reached, is shown to be temperature dependent based on the crack tip stress field calculated by the finite element method. With the J-A2 two-parameter constraint theory in fracture mechanics, the fracture toughness (JC or KJC) can be expressed as a function of the constraint level (A2) and the critical distance rc. This relationship is used to predict the fracture toughness of A533B-1 in the ductile-brittle transition regime with a constant σf and a set of temperature-dependent rc. It can be shown that the prediction agrees well with the test data for wide range of constraint levels from shallow cracks (a/W = 0.075) to deep cracks (a/W = 0.5), where a is the crack length and W is the specimen width.

scholarly journals Numerical Simulation on Carbonation Depth of Concrete Structures considering Time- and Temperature-Dependent Carbonation Process

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Jianxin Peng ◽  
Huang Tang ◽  
Jianren Zhang ◽  
Steve C. S. Cai
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Concrete Structures ◽  
Element Model ◽  
Temperature Dependent ◽  
Mass Transfer Equation ◽  
Carbonation Depth ◽  
Concrete Carbonation ◽  
Carbonation Process ◽  
Element Method

In order to further understand the carbonation process of concrete structures, the time- and temperature-dependent diffusion process of CO2 in concrete is simulated based on the law of the CO2 mass conservation, and a two-dimensional mass transfer equation is established for the CO2 diffusion in concrete. The concrete block is discretized into triangular elements, and the CO2 concentrations at different positions are calculated based on finite element method. A computational algorithm is programed through the Matlab platform. The time- and temperature-dependent property and difference of the CO2 concentration at different positions of the structure are considered in the proposed model. Then, an accelerated carbonation experiment is carried out using concrete blocks with different mix proportions to investigate the influence of the water-cement ratio and temperature on the concrete carbonation. The experimental results effectively verify the correctness of the finite element model, and the proposed finite element method reasonably simulates the concrete carbonation through calculating the carbonation in practical engineering compared with other methods in references. An experimental-numerical correlation has been performed. The ratio of carbonation depth at the corner of the concrete members to the other positions is about 1.35. The carbonation depth is increased about 1.9 times when the temperature changes from 20°C to 40°C.

Complex Fractional-Spectral Method for Space Curved Struts: Theory and Application

1997 ◽  
Vol 12 (2) ◽  
pp. 59-67 ◽  
Author(s):  
A.M. Horr ◽  
L.C. Schmidt
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Spectral Element Method ◽  
Spectral Element ◽  
Structural Systems ◽  
Temperature Dependent ◽  
Large Structures ◽  
Damping Characteristics ◽  
Stability And Accuracy ◽  
Element Method

Based on the theory of fractional calculus and the complex spectral theory of vibration, a new spectrally-formulated finite-element method of analysis is developed which is capable of making accurate predictions of the dynamic response of damped structures with curved struts. The frequency-dependent and temperature-dependent damping characteristics of structural materials can be modelled accurately using the fractional derivative model. The main features of the complex-spectral element method of analysis are presented in this paper. Although most structural systems can be analysed and designed by using the conventional finite element method, in order to guarantee stability and accuracy of the solution the number of elements used to model the structure may be very large. Hence, it appears that, for large structures, it may be more effective to use the spectral approach presented in this paper.

Effect of rotation on plane waves in generalized thermomicrostretch elastic solid: comparison of different theories using finite element method

2014 ◽  
Vol 92 (10) ◽  
pp. 1269-1277 ◽  
Author(s):  
Mohamed I.A. Othman ◽  
Ibrahim A. Abbas
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Plane Waves ◽  
Relaxation Times ◽  
Generalized Thermoelasticity ◽  
Elastic Solid ◽  
Presence And Absence ◽  
Effects Of Rotation ◽  
Coupled Theory ◽  
Element Method

The present investigation is aimed at studying the effect of rotation on the thermomicrostretch elastic solid. The formulation is applied in the context of the generalized thermoelasticity Lord–Şhulman theory with one relaxation time and Green–Lindsay’s theory with two relaxation times, as well as the classical dynamical coupled theory. The problem has been solved numerically using a finite element method. Numerical results for the temperature distribution, the displacement components, the force stresses, the couple stresses, and the microstress distribution are represented graphically. The results indicate that the effects of rotation are very pronounced. Comparisons are made with the results in the presence and absence of rotation and in the presence and absence of microstretch constants between the two theories.

Finite Element Verification of Transmission Conditions for Thin Reactive Heat-Conducting Interphases

2008 ◽  
Vol 273-276 ◽  
pp. 400-405 ◽  
Author(s):  
Andreas Öchsner ◽  
Wiktoria Miszuris
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Heat Conduction ◽  
Intermediate Layer ◽  
Transmission Conditions ◽  
Heat Conducting ◽  
The Finite Element Method ◽  
Temperature Dependent ◽  
Bonded Materials ◽  
Element Method

Imperfect transmission conditions modelling a thin reactive 2D intermediate layer between two bonded materials in a dissimilar strip have been derived and analytically analysed in another paper of this issue. In this paper, the validity of these transmission conditions for heat conduction problems has been investigated due to the finite element method (FEM) for two formulations of a reactive layer: namely, based on a constant and a temperature-dependent source or sink formulation. It is shown that the accuracy of the transmission conditions is excellent for the investigated examples.

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