scholarly journals Solution of Nonlinear Coupled Heat and Moisture Transport Using Finite Element Method

10.14311/622 ◽  
2004 ◽  
Vol 44 (5-6) ◽  
Author(s):  
T. Krejčí
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Moisture Transfer ◽  
Coupled Problems ◽  
Algebraic Equations ◽  
Capillary Pressures ◽  
Coupled Heat And Moisture ◽  
Attention Systems ◽  
Heat And Moisture ◽  
Element Method

This paper deals with a numerical solution of coupled of heat and moisture transfer using the finite element method. The mathematical model consists of balance equations of mass, energy and linear momentum and of the appropriate constitutive equations. The chosen macroscopic field variables are temperature, capillary pressures, gas pressure and displacement. In contrast with pure mechanical problems, there are several difficulties which require special attention. Systems of algebraic equations arising from coupled problems are generally nonlinear, and the matrices of such systems are nonsymmetric and indefinite. The first experiences of solving complicated coupled problems are mentioned in this paper. 

Modelling of Heat and Moisture Transfer Phenomena During Dry Biscuit Baking by Using Finite Element Method

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Enrico Ferrari ◽  
Simone V. Marai ◽  
Riccardo Guidetti ◽  
Laura Piazza
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Moisture Transfer ◽  
Continuous Functions ◽  
Transfer Model ◽  
The Finite Element Method ◽  
Baking Process ◽  
Heat And Moisture ◽  
The Mathematical Model ◽  
Element Method

Abstract This paper validates a simultaneous heat and mass transfer model proposed to describe the discontinuous biscuit baking process. The mathematical model includes the moving evaporation front and the development of the crust observed during the baking process. The problem is solved over a two-dimensional geometry using the finite element method. Thermo-physical properties were computed by means of continuous functions. Variations in temperature and water content during baking were predicted with high to discrete accuracy using this model.

A Model for Assessment of Heat and Moisture Transfer Hollow a Hemp Concerte Wall Using Finite Element Method

2022 ◽  
Author(s):  
Salah Ouldboukhitine ◽  
Sofiane Amziane ◽  
Maroua Benkhaled
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Energy Consumption ◽  
Moisture Transfer ◽  
Energy Performance ◽  
Vapor Permeability ◽  
Heat And Moisture Transfer ◽  
Concrete Wall ◽  
Heat And Moisture ◽  
Element Method

The energy performance of buildings represents a major challenge in terms of sustainable development. The buildings and buildings construction sectors combined are responsible for over one-third of global final energy consumption and nearly 40% of total direct and indirect CO2 emissions. In order to reduce the energy consumption of buildings and their harmful impact on the environment, special attention has been paid in recent years to the use of bio-based materials. In the present paper, a model of heat and moisture transfer hollow hemp concrete wall is proposed using finite element method. The energy and mass balances are expressed using measurable transfer drivers as temperature water content and vapor pressure and coefficients related explicitly to the macroscopic properties of material as thermal conductivity, specific heat, and water vapor permeability. The proposed model is implemented in MATLAB code and validated through experimental measurements.

scholarly journals A 1D Model for Predicting Heat and Moisture Transfer through a Hemp-Concrete Wall Using the Finite-Element Method

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6903
Author(s):  
Maroua Benkhaled ◽  
Salah-Eddine Ouldboukhitine ◽  
Amer Bakkour ◽  
Sofiane Amziane
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Moisture Transfer ◽  
Construction Material ◽  
Climatic Conditions ◽  
Vapor Permeability ◽  
Transfer Model ◽  
The Finite Element Method ◽  
Concrete Wall ◽  
Element Method

Plant-based concrete is a construction material which, in addition to having a very low environmental impact, exhibits excellent hygrothermal comfort properties. It is a material which is, as yet, relatively unknown to engineers in the field. Therefore, an important step is to implement reliable mass-transfer simulation methods. This will make the material easy to model, and facilitate project design to deliver suitable climatic conditions. In recent decades, numerous studies have been carried out to develop models of the coupled transfers of heat, air and moisture in porous building envelopes. Most previous models are based on Luikov’s theory, considering mass accumulation, air and total pressure gradient. This theory considers the porous medium to be homogeneous, and therefore allows for hygrothermal transfer equations on the basis of the fundamental principles of thermodynamics. This study presents a methodology for solving the classical 1D (one-dimensional) HAM (heat, air, and moisture) hygrothermal transfer model with an implementation in MATLAB. The resolution uses a discretization of the problem according to the finite-element method. The detailed solution has been tested on a plant-based concrete. The energy and mass balances are expressed using measurable transfer quantities (temperature, water content, vapor pressure, etc.) and coefficients expressly related to the macroscopic properties of the plant-based concrete (thermal conductivity, specific heat, water vapor permeability, etc.), determined experimentally. To ensure this approach is effective, the methodology is validated on a test case. The results show that the methodology is robust in handling a rationalization of the model whose parameters are not ranked and not studied by their degree of importance.

The Combination of Multi-Step Differential Transformation Method and Finite Element Method in Vibration Analysis of Non-Prismatic Beam

2017 ◽  
Vol 09 (01) ◽  
pp. 1750010 ◽  
Author(s):  
Ryszard Hołubowski ◽  
Kamila Jarczewska
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Transformation Method ◽  
Differential Transformation Method ◽  
Algebraic Equations ◽  
Differential Transformation ◽  
Prismatic Beam ◽  
Time Histories ◽  
Euler Bernoulli Beam ◽  
Element Method

The paper presents a new algorithm being the combination of multi-step differential transformation method (MsDTM) and finite element method (FEM) as a powerful tool for solving variety dynamic problems. The proposed algorithm, named as differential transformation finite element method (DTFEM), transforms partial differential equation into a set of recursive algebraic equations. The final form of a solution is a piecewise function which in general case may be a symbolic function. High effectiveness and accuracy of DTFEM is demonstrated on the example of forced vibrations of non-prismatic Euler–Bernoulli beam. Computed time histories of displacements, velocities and accelerations are highly consistent with results obtained by Newmark method.

scholarly journals Application of the finite element method to solving the duffing equation of ground motion

2020 ◽  
Vol 26 (1) ◽  
pp. 65-71
Author(s):  
Godwin C.E. Mbah ◽  
Kingsley Kelechi Ibeh
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Duffing Equation ◽  
Weight Functions ◽  
Algebraic Equations ◽  
Galerkin Finite Element Method ◽  
Galerkin Finite Element ◽  
Minimization Technique ◽  
The Galerkin Method ◽  
Element Method

In this paper, we applied the Galerkin Finite Element Method to solve a damped, externally forced, second order ordinary differential equation with cubic nonlinearity known as the Duffing Equation. The Galerkin method uses the functional minimization technique which sets the equation in systems of algebraic equations to be solved. Various simulation on the effect of change on some parametric values of the Duffing equation are shown. Keywords: Galerkin Finite Element Method, stiffness matrix, Duffing Equation, shape functions, basis functions, weight functions.

Proposal of Finite Element Method for Structure-Piezoelectric-Circuit Coupled Problems

2019 ◽  
Vol 2019.32 (0) ◽  
pp. 276
Author(s):  
Rei TAKATA ◽  
Daisuke ISHIHARA ◽  
Prakasha Chigahalli RAMEGOWDA ◽  
Tomoya NIHO ◽  
Tomoyoshi HORIE
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Coupled Problems ◽  
Element Method

An Analysis of the Large Deflections of Beams using the Rayleigh-Ritz Finite Element Method

1968 ◽  
Vol 19 (4) ◽  
pp. 357-367 ◽  
Author(s):  
A. C. Walker ◽  
D. G. Hall
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Method ◽  
Large Deflection ◽  
Energy Functional ◽  
Algebraic Equations ◽  
Linear Algebraic Equations ◽  
Non Linear ◽  
Comparison Of The Results ◽  
Element Method

SummaryThe Rayleigh-Ritz finite element method is used to obtain an approximate solution of the exact non-linear energy functional describing the large deflection bending behaviour of a simply-supported inextensible uniform beam subjected to point loads. The solution of the non-linear algebraic equations resulting from the use of this method is effected, using three different techniques, and comparisons are made regarding the accuracy and computing effort involved in each. A description is given of an experimental investigation of the problem and comparison of the results with those of the numerical method, and of the available exact continuum analyses, indicates that the numerical method provides satisfactory predictions for the non-linear beam behaviour for deflections up to one quarter of the beam’s length.

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