On the Use of Fully Three Dimensional Multifield Mixed Finite Element
Scheme in Multiscale Structural and Building Energy Efficiency
Simulations
Dubravka Mijuca
Faculty of Mathematics, Department of Mechanics,
University of Belgrade, Serbia
Thursday, June 28, 2007 15:00-16:00,
Building 101, Lecture Room A
Gaithersburg
Thursday, June 28, 2007 13:00-14:00,
Room 4550
Boulder
Abstract:
The multiscale robust original fully three dimensional primal mixed finite
element approach in thermo-mechanical solid mechanics, which can bridge
simulations on micro, meso and nano levels, will be presented in detail. The
first goal was to develop a numerical simulation procedure that enables the
thermo-mechanical analysis of the megastructure, from macro to microscale and
atomistic levels, in one simulation framework. The second goal was to develop
a reliable procedure that will enable the highest level of interoperability
between structural and energy efficiency in the civil construction sector.
Contemporary hardware and mathematical resources to handle large scale computing
open doors for richer FE theories in which reliability is not compromised, even
if the model problem to be analyzed requires consideration through geometrical
scales from continuum to micro to nanomechanics. In addition, integral energy
efficiency can be approached by very fine thermal modeling of small details, for
example, thermal bridges in wall systems that include metal bolts. The
reliability of the present
approach relies on the robustness of the underlying primal
mixed finite element scheme, which is insensitive to extreme distortion of
hexahedral finite elements. The essential contribution of the present approach
is to enforce the continuity of the dual variables, stress and heat flux,
everywhere on the body and consequently on the surfaces of material
discontinuity. This enables reliability,
as well as smooth behavior of the primal
variable (displacement and temperature) in the vicinity of singularity. The
application of this technique in industrial problems that require multiscale
simulation includes composite sandwiched plates with foam in its core,
fiberoptic sensors embedded in composite materials, and microcoating technology.
The final example is a simulation of the building envelope, as an integral part
of energy efficiency assessment in the residential sector by contemporary
simulation tools, such as EnergyPlus (http://www.energyplus.gov).
Speaker Bio:
Dubravka Mijuca is a Professor in the Department of Mechanics at Faculty of
Mathematics University of Belgrade, Serbia, where she received her MSc and PhD
in Computational Mechanics. Her research interests include the novel and
reliable fully three-dimensional multifield mixed finite element procedures in
thermomechanics for the isotropic, anisotropic and composite bodies with
material interfaces, which can be bridged with simulations on micro and nano
geometrical levels, without spurious oscillations of the results. The main goal
in her research is reliable mechanical and thermal stress calculation on
material interfaces, such as, interface between plies in composite, and over
the interface of the coating, as well nonphysical interfaces, such as interface
between boundary of the macro and nano simulation levels. In addition, her
research interest, beside structural efficiency is also in simulation of the
energy efficiency of buildings, influence of thermal characteristic of building
envelope throughout the geometrical scales on integral energy efficiency of
buildings, and interoperability of these two simulations. She is a vice
president of Serbian Society of
Computational Mechanics, member of general council
of Serbian Society of Mechanics, member of NAFEMS and IUTAM. Professor Mijuca's
publications have appeared in the journals Computational Mechanics,
Computer Assisted Mechanics and Engineering Sciences,
Facta Mechanics and Thermal Science.
She has published a monograph entitled
On Primal-Mixed formulation in Elasticity and Thermoelasticity.
Contact: G. B. McFaddenNote: Visitors from outside NIST must contact
Robin Bickel; (301) 975-3668;
at least 24 hours in advance.
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