V International Conference on Computational Methods for Coupled Problems in Science and Engineering (COUPLED 2013) Santa Eulàlia, Ibiza, Spain, 17-19 June, 2013
http://hdl.handle.net/2117/190787
A conference celebrating the 60th birthday of Eugenio Oñate2021-04-21T07:05:28ZA fully coupled thermo-hydro-mechanical model for the analysis of the lining behavior of underground caverns in an AA-CAES system
http://hdl.handle.net/2117/192864
A fully coupled thermo-hydro-mechanical model for the analysis of the lining behavior of underground caverns in an AA-CAES system
El Murr, Anis; Hadj-Hassen, Faouzi; Rouabhi, Ahmed; Tijani, Michel
With the worldwide demand for electricity, renewable energy is attracting
increasing attention. As this energy has an intermittent character, large-scale storage
technologies are necessary. One of the most promising systems is the advanced adiabatic
compressed air energy storage (AA-CAES) in underground lined rock caverns. The high
cyclic thermal and mechanical loadings involved in the system can disturb the surrounding
geological barrier and thus lead to the failure of the system. The implementation of a special
lining capable of limiting the thermal losses, reducing the air leakage and ensuring the caverns
stability, is therefore required.
This paper presents the governing equations for fully coupled thermo-hydro-mechanical
(THM) processes in saturated deformable media filled with dry air which characterize the
conditions of the storing system. The assumptions used to simplify the equations are
discussed and the neglected terms are underlined. These equations take into account the
dependence of thermal conductivity on temperature, convection and heat compression. The air
properties are derived using Helmholtz energy. A comprehensive comparison between the
proposed model and a simple THM model based on constant parameters, ideal gas and
conductive flux is made in order to emphasize the phenomena that could occur and their
influences. Finally, thermo-hydro-mechanical simulations of the different lining materials are
carried out to analyze the advantages and the drawbacks of each solution.
2020-07-10T17:21:05ZEl Murr, AnisHadj-Hassen, FaouziRouabhi, AhmedTijani, MichelWith the worldwide demand for electricity, renewable energy is attracting
increasing attention. As this energy has an intermittent character, large-scale storage
technologies are necessary. One of the most promising systems is the advanced adiabatic
compressed air energy storage (AA-CAES) in underground lined rock caverns. The high
cyclic thermal and mechanical loadings involved in the system can disturb the surrounding
geological barrier and thus lead to the failure of the system. The implementation of a special
lining capable of limiting the thermal losses, reducing the air leakage and ensuring the caverns
stability, is therefore required.
This paper presents the governing equations for fully coupled thermo-hydro-mechanical
(THM) processes in saturated deformable media filled with dry air which characterize the
conditions of the storing system. The assumptions used to simplify the equations are
discussed and the neglected terms are underlined. These equations take into account the
dependence of thermal conductivity on temperature, convection and heat compression. The air
properties are derived using Helmholtz energy. A comprehensive comparison between the
proposed model and a simple THM model based on constant parameters, ideal gas and
conductive flux is made in order to emphasize the phenomena that could occur and their
influences. Finally, thermo-hydro-mechanical simulations of the different lining materials are
carried out to analyze the advantages and the drawbacks of each solution.Probability and variance-based stochastic design optimization of a radial compressor concerning fluid-structure interaction
http://hdl.handle.net/2117/192863
Probability and variance-based stochastic design optimization of a radial compressor concerning fluid-structure interaction
Roos, Dirk; Cremanns, Kevin; Jasper, Tim
Since the engineering of turbo machines began the improvement of specific
physical behaviour, especially the efficiency, has been one of the key issues.
However, improvement of the efficiency of a turbo engine, is hard to archive using a
conventional deterministic optimization, since the geometry is not perfect and many
other parameters vary in the real approach.
In contrast, stochastic design optimization is a methodology that enables the
solving of optimization problems which model the effects of uncertainty in manufacturing,
design configuration and environment, in which robustness and reliability are
explicit optimization goals. Therein, a coupling of stochastic and optimization problems
implies high computational efforts, whereby the calculation of the stochastic
constraints represents the main effort. In view of this fact, an industrially relevant
algorithm should satisfy the conditions of precision, robustness and efficiency.
In this paper an efficient approach is presented to assist reducing the number of
design evaluations necessary, in particular the number of nonlinear fluid-structure
interaction analyses. In combination with a robust estimation of the safety level
within the iteration and a final precise reliability analysis, the method presented
is particularly suitable for solving reliability-based structural design optimization
problems with ever-changing failure probabilities of the nominal designs.
The applicability for real case applications is demonstrated through the example
of a radial compressor, with a very high degree of complexity and a large number of
design parameters and random variables.
2020-07-10T17:16:43ZRoos, DirkCremanns, KevinJasper, TimSince the engineering of turbo machines began the improvement of specific
physical behaviour, especially the efficiency, has been one of the key issues.
However, improvement of the efficiency of a turbo engine, is hard to archive using a
conventional deterministic optimization, since the geometry is not perfect and many
other parameters vary in the real approach.
In contrast, stochastic design optimization is a methodology that enables the
solving of optimization problems which model the effects of uncertainty in manufacturing,
design configuration and environment, in which robustness and reliability are
explicit optimization goals. Therein, a coupling of stochastic and optimization problems
implies high computational efforts, whereby the calculation of the stochastic
constraints represents the main effort. In view of this fact, an industrially relevant
algorithm should satisfy the conditions of precision, robustness and efficiency.
In this paper an efficient approach is presented to assist reducing the number of
design evaluations necessary, in particular the number of nonlinear fluid-structure
interaction analyses. In combination with a robust estimation of the safety level
within the iteration and a final precise reliability analysis, the method presented
is particularly suitable for solving reliability-based structural design optimization
problems with ever-changing failure probabilities of the nominal designs.
The applicability for real case applications is demonstrated through the example
of a radial compressor, with a very high degree of complexity and a large number of
design parameters and random variables.Optimal actuator and sensor placement with regard to coupled electro-mechanical behaviour of smart structures
http://hdl.handle.net/2117/192862
Optimal actuator and sensor placement with regard to coupled electro-mechanical behaviour of smart structures
Nestorovic, Tamara; Trajkov, Miroslav
In this paper the problem of optimal actuator and sensor placement for active large
flexible structures is considered. The proposed placement optimization method is based on
balanced reduced models. It overcomes disadvantages arising from demanding numeric
procedures related with high order structural models. Optimization procedure relies on H2 and
H∞ norms, as well as on controllability and observability Gramians, related with structural
eigenmodes of interest. The optimization procedure is documented by examples, which show
a good agreement between the results obtained using different placement indices.
2020-07-10T17:12:59ZNestorovic, TamaraTrajkov, MiroslavIn this paper the problem of optimal actuator and sensor placement for active large
flexible structures is considered. The proposed placement optimization method is based on
balanced reduced models. It overcomes disadvantages arising from demanding numeric
procedures related with high order structural models. Optimization procedure relies on H2 and
H∞ norms, as well as on controllability and observability Gramians, related with structural
eigenmodes of interest. The optimization procedure is documented by examples, which show
a good agreement between the results obtained using different placement indices.Use of a BEM model to simulate unsteady Coupled heat and moisture flow through porous solid
http://hdl.handle.net/2117/192861
Use of a BEM model to simulate unsteady Coupled heat and moisture flow through porous solid
Skerget, L.; Tadeu, A.
The problem of unsteady coupled moisture and heat energy transport through
porous solid is studied numerically using singular boundary integral representation of the
corresponding governing equations. Bench mark example moisture uptake in a semiinfinite
region is studied numerically.
2020-07-10T17:09:56ZSkerget, L.Tadeu, A.The problem of unsteady coupled moisture and heat energy transport through
porous solid is studied numerically using singular boundary integral representation of the
corresponding governing equations. Bench mark example moisture uptake in a semiinfinite
region is studied numerically.Two dimensional solution of the advection-diffusion equation using two collocation methods with local upwinding RBF
http://hdl.handle.net/2117/192860
Two dimensional solution of the advection-diffusion equation using two collocation methods with local upwinding RBF
Granados, Julian M.; Bustamante, Carlos A.; Power, Henry; Florez, Whady F.
The two-dimensional advection-diffusion equation is solved using two local
collocation methods with Multiquadric (MQ)Radial Basis Functions (RBFs). Although
both methods use upwinding, the first one, similar to the method of Kansa, approximates
the dependent variable with a linear combination of MQs. The nodes are grouped into
two types of stencil: cross-shaped stencil to approximate the Laplacian of the variable
and circular sector shape stencil to approximate the gradient components. The circular
sector opens in opposite to the flow direction and therefore the maximum number of nodes
and the shape parameter value are selected conveniently. The second method is based
on the Hermitian interpolation where the approximation function is a linear combination
of MQs and the resulting functions of applying partial differential equation (PDE) and
boundary operators to MQs, all of them centred at different points. The performance
of these methods is analysed by solving several test problems whose analytical solutions
are known. Solutions are obtained for different Peclet numbers, Pe, and several values
of the shape parameter. For high Peclet numbers the accuracy of the second method
is affected by the ill-conditioning of the interpolation matrix while the first interpolation method requires the introduction of additional nodes in the cross stencil. For low Pe both
methods yield accurate results. Moreover, the first method is employed to solve the twodimensional
Navier-Stokes equations in velocity-vorticity formulation for the lid-driven
cavity problem moderate Pe.
2020-07-10T17:05:37ZGranados, Julian M.Bustamante, Carlos A.Power, HenryFlorez, Whady F.The two-dimensional advection-diffusion equation is solved using two local
collocation methods with Multiquadric (MQ)Radial Basis Functions (RBFs). Although
both methods use upwinding, the first one, similar to the method of Kansa, approximates
the dependent variable with a linear combination of MQs. The nodes are grouped into
two types of stencil: cross-shaped stencil to approximate the Laplacian of the variable
and circular sector shape stencil to approximate the gradient components. The circular
sector opens in opposite to the flow direction and therefore the maximum number of nodes
and the shape parameter value are selected conveniently. The second method is based
on the Hermitian interpolation where the approximation function is a linear combination
of MQs and the resulting functions of applying partial differential equation (PDE) and
boundary operators to MQs, all of them centred at different points. The performance
of these methods is analysed by solving several test problems whose analytical solutions
are known. Solutions are obtained for different Peclet numbers, Pe, and several values
of the shape parameter. For high Peclet numbers the accuracy of the second method
is affected by the ill-conditioning of the interpolation matrix while the first interpolation method requires the introduction of additional nodes in the cross stencil. For low Pe both
methods yield accurate results. Moreover, the first method is employed to solve the twodimensional
Navier-Stokes equations in velocity-vorticity formulation for the lid-driven
cavity problem moderate Pe.Semi-analytical approach for ratcheting strain and wear prediction in case of line rolling contact
http://hdl.handle.net/2117/192859
Semi-analytical approach for ratcheting strain and wear prediction in case of line rolling contact
Sofer, M.; Halama, R.
The most studies in the field of rolling contact fatigue and wear consider that these
phenomenons are independent, but this paper shows strong coupling of both in the case, when
ratcheting mechanism is the driving one. There is presented the application of semi-analytical
approach, introduced by A. Mazzu [1], for two dimensional rolling contact case. The model is
based on non-linear kinematic and isotropic hardening rule of Chaboche and Lemaitre [2].
Mazzu´s approach has been modified to correctly predict ratcheting and wear rate for different
values of contact pressure. A correlation between the parameter L (yield stress) and the value
of the maximum contact pressure p0 has been found. All performed simulations are based on
rolling contact fatigue tests realized on author´s department [3].
2020-07-10T17:02:19ZSofer, M.Halama, R.The most studies in the field of rolling contact fatigue and wear consider that these
phenomenons are independent, but this paper shows strong coupling of both in the case, when
ratcheting mechanism is the driving one. There is presented the application of semi-analytical
approach, introduced by A. Mazzu [1], for two dimensional rolling contact case. The model is
based on non-linear kinematic and isotropic hardening rule of Chaboche and Lemaitre [2].
Mazzu´s approach has been modified to correctly predict ratcheting and wear rate for different
values of contact pressure. A correlation between the parameter L (yield stress) and the value
of the maximum contact pressure p0 has been found. All performed simulations are based on
rolling contact fatigue tests realized on author´s department [3].Science & engineering software migration: moving from desktop to mobile applications
http://hdl.handle.net/2117/192858
Science & engineering software migration: moving from desktop to mobile applications
Améndola, Federico; Favre, Liliana
The proliferation of mobile devices over the last years provides opportunities and
challenges for solving problems in science and engineering. Among other novel features,
mobile devices contain global positioning sensors, wireless connectivity, built-in web
browsers and photo/video/voice capabilities that allow providing highly localized, context
aware applications. Mobile phones have become as powerful as any desktop computer in
terms of applications they can run. However, the software development in mobile computing
is still not as mature as it is for desktop computer and the whole potential of mobile devices is
wasted [7, 8].
2020-07-10T16:59:58ZAméndola, FedericoFavre, LilianaThe proliferation of mobile devices over the last years provides opportunities and
challenges for solving problems in science and engineering. Among other novel features,
mobile devices contain global positioning sensors, wireless connectivity, built-in web
browsers and photo/video/voice capabilities that allow providing highly localized, context
aware applications. Mobile phones have become as powerful as any desktop computer in
terms of applications they can run. However, the software development in mobile computing
is still not as mature as it is for desktop computer and the whole potential of mobile devices is
wasted [7, 8].Network models for the numerical solution of coupled ordinary non-lineal differential equations
http://hdl.handle.net/2117/192857
Network models for the numerical solution of coupled ordinary non-lineal differential equations
Alhama, Iván; Morales, José L.; Alhama, Francisco
Many apparently simple problems in mechanics or mechanical engineering,
particularly problems related to chaotic systems, are governing by coupled differential
equations, generally non-lineal, that have to be solved numerically by specialists in this field.
The network model, a tool very used in the last decades for numerical problems in different
fields of science and engineering, allows that non-specialists, and even students familiarized
with circuits theory, to design networks whose governing equations are just those of the
engineering phenomenon, assuming a suitable or formal equivalence between electrical and
physical variables. The design of the model, which is composed of a principal network, which
implements a balance between the addends of the differential equations, and auxiliary
networks to implement the derivative terms, follows a standard procedure. Non-lineal terms
of the differential equations are implemented by a controlled source, a kind of device whose
operation is quite intuitive. In this communication the models of two characteristic non-lineal
mechanical problems are designed step by step with a detailed explanation: the elastic
pendulum and the chaotic double pendulum: Solutions are presented graphically by using
MATLAB.
2020-07-10T16:57:14ZAlhama, IvánMorales, José L.Alhama, FranciscoMany apparently simple problems in mechanics or mechanical engineering,
particularly problems related to chaotic systems, are governing by coupled differential
equations, generally non-lineal, that have to be solved numerically by specialists in this field.
The network model, a tool very used in the last decades for numerical problems in different
fields of science and engineering, allows that non-specialists, and even students familiarized
with circuits theory, to design networks whose governing equations are just those of the
engineering phenomenon, assuming a suitable or formal equivalence between electrical and
physical variables. The design of the model, which is composed of a principal network, which
implements a balance between the addends of the differential equations, and auxiliary
networks to implement the derivative terms, follows a standard procedure. Non-lineal terms
of the differential equations are implemented by a controlled source, a kind of device whose
operation is quite intuitive. In this communication the models of two characteristic non-lineal
mechanical problems are designed step by step with a detailed explanation: the elastic
pendulum and the chaotic double pendulum: Solutions are presented graphically by using
MATLAB.Model identification and on-line optimal control of food processes
http://hdl.handle.net/2117/192856
Model identification and on-line optimal control of food processes
Balsa-Canto, E.; Alonso, A.A.; Antelo, L.T.; Arias-Méndez, A.; López-Quiroga, E.; Rivas, D.; Vilas, C.
Food processes are coupled systems that involve heat, mass and momentum
transfer together with kinetic processes related to quality and safety. This work is devoted
to illustrate how model-based techniques offer the possibility to rationally optimise processes
even in real time. The contribution is mainly based on our group experience and
illustrates concepts with several examples such as the refrigeration of fruits, the deep-fat
frying of potato chips, the freeze-drying of dairy products and the thermal processing of
packaged foods. Coupled Problems 2013 Conference.
2020-07-10T16:53:17ZBalsa-Canto, E.Alonso, A.A.Antelo, L.T.Arias-Méndez, A.López-Quiroga, E.Rivas, D.Vilas, C.Food processes are coupled systems that involve heat, mass and momentum
transfer together with kinetic processes related to quality and safety. This work is devoted
to illustrate how model-based techniques offer the possibility to rationally optimise processes
even in real time. The contribution is mainly based on our group experience and
illustrates concepts with several examples such as the refrigeration of fruits, the deep-fat
frying of potato chips, the freeze-drying of dairy products and the thermal processing of
packaged foods. Coupled Problems 2013 Conference.Modal analysis of the fgm beam-like structures with effect of the thermal axial force
http://hdl.handle.net/2117/192855
Modal analysis of the fgm beam-like structures with effect of the thermal axial force
Murín, Justín; Aminbaghai, Mehdi; Hrabovsky, Juraj; Kutis, Vladimir; Paulech, Juraj
The modal analysis of the FGM beam-like actuator is presented, where effects of
the thermal axial force and the shear force are considered. The temperature load is assumed to
be lower as the critical buckling temperature. The longitudinal variation of material properties
has been assumed which can be caused by the varying constituent’s volume fraction and the
temperature dependence of the constituent’s material properties. Our new FGM beam finite
element has been used in the proposed analysis. An influence of the material properties
variation and the thermal axial forces on the actuator eigenfrequency and eigenform has been
studied and discussed.
2020-07-10T16:49:12ZMurín, JustínAminbaghai, MehdiHrabovsky, JurajKutis, VladimirPaulech, JurajThe modal analysis of the FGM beam-like actuator is presented, where effects of
the thermal axial force and the shear force are considered. The temperature load is assumed to
be lower as the critical buckling temperature. The longitudinal variation of material properties
has been assumed which can be caused by the varying constituent’s volume fraction and the
temperature dependence of the constituent’s material properties. Our new FGM beam finite
element has been used in the proposed analysis. An influence of the material properties
variation and the thermal axial forces on the actuator eigenfrequency and eigenform has been
studied and discussed.