news in comsol multiphysics 3.2 place prague 2005-11-15 bertil waldén comsol ab
TRANSCRIPT
FEMLAB is now COMSOL MultiphysicsTM
• First name was PDE Toolbox– Because it solved PDEs
• Second name was FEMLAB– Because it made use of the Finite Element Method
• Now we are dealing with Multiphysics and want a name that expresses this
• Name structure – same product and company name– Not all future products will be FEM or FEA based
New Products
• COMSOL ScriptTM
• CAD Import Module
• Add-ons to the CAD Import Module– Pro/E Import Module– CATIA V4 Import Module– CATIA V5 Import Module– Inventor Import Module– VDA-FS Import Module
Programming language and fast graphics
COMSOL Script:• Fully compatible with the MATLAB language
– All data types except objects– Command line debugger, dbstop, dbstep, dbcont, ...– Java interface
• Fast 3D graphics using OpenGL acceleration (50 times faster than Matlab)
Batch execution with COMSOL Script
• Requested feature that allow several simulations to run sequentially or simultaneously
• The simulation can be distributed over a network to run on different machines
• COMSOL Script executes an M-file that defines the simulation
Support for units
• Metric units– SI units – CGS units– MPa units suitable
for structural analys– EM units– ES units
• English units– British engineering
units– FPS– IPS– Gravitational IPS
• No units
More improvements
For constants and expressions:• save and open • add descriptive comments
• Customized report
Select the content of your report
New material library functionality
• Support for anisotropic materials and orthotropic materials – Both the 6-by-6 elasticity matrix in 3D and the 4-by-4
elasticity matrix in 2D are supported.
• Support for piezoelectric materials– The piezoelectric matrices: elasticity matrix, coupling
matrix and permittivity matrix are supported.
• Support for elastic-plastic and hyperelastic materials• Material functions can be specified
– For example: temperature dependent material properties
• Further develop the solvers to solve MUCH larger problems MUCH MUCH faster– Built-in support for wave equations (DOFs reduced with 50%,
iterative solvers more efficient)– 5-10 times larger CFD problems solved with new multigrid
smoother (Vanka) for laminar flow (tested), turbulent flow (tested), arbitrary multiphysics problems (not tested)
– A bunch of under-the-hood improvements on mesh stability, incomplete LU preconditioner, file storage of solutions (during transient solving)
Performance Improvements:
Wave Equations in 3.1 and 3.2:
• 3.1: Substitution– Unsymmetric Jacobian matrix with
zeros on the diagonal– Not good for iterative solvers– Memory waste– Two dofs to keep track of
• 3.2: New formulation– One variable, symmetric Jacobian if
the PDE is – Very good for iterative solvers!
– Memory efficient!
0
a
vd c u f
tuv
t
fuct
ud
t
ue aa
2
2
Transient analysis improvements
• Time derivatives can be used freely in expressions:– Logical names: ut, utt, uxt, uxtt– Reduces the number of degrees of freedom in your models.– Memory and solution times significantly improved.– Store solution on file.
New ODE Interface
• Type in ODE as it is: ut-u=0• Creates a global DOF• Easier to use than Weak Form,
Point
New CFD Benchmark: Turek's
• Laminar flow, 3D• On 32-bit architecture, 2GB RAM: 450 kdofs, 60-90
minutes– In 3.1, 240 kdofs, 4-5 hours
• On 64-bit architecture, 12 GB RAM: 2150 kdofs, 6-8 hours– In 3.1, 400-500 kdofs, 16 hours
Moving meshes with ALE• ALE is a technique used to handle single physics or multiphysics problems
where the effect of the deformation on the physics cannot be neglected. • A simple example of this is the 2D fluid structure interaction model:
Original mesh Deformed mesh
• ALE smooths out the mesh deformations in the entire domain in a diffusive manner
• Analogy: Think of the mesh element edges as interconnected springs which are compressed or extended due to prescribed deformations on the boundary or in the subdomain
Moving meshes with ALE
Objective
• To make it possible to automate modification of geometry without resorting to command line
• The changes made to the geometry can be for example translation or scaling of a given geometry object
Simple example of Parameterized Geometry
Distributed heat source
All boundares kept at T=288 K
Moving drilled hole (mesh deformation)
• ”Catch” parts of COMSOL Multiphysics in your own easy-to-use windows.
• Create a GUI of your own that can run all types of scripts: COMSOL Multiphysics or user-defined.
• Uniqe function: customized GUIs work with all types user functions for all types of analysis!
New in COMSOL 3.2: Customized GUIs
How to do?
Two simple steps:
1. Create a Java component through a simple script
2. Run your own script functions through a GUI event (push a button)
Why customized GUIs?
• Perfect for teaching.• Allow the user to generate simplified GUI for
customized problem.• Non specialist engineer can do a finite element
analysis.• Consultancy company that can provide a study to
their own customer.• Design engineer that are not specialized in FE
analysis for quick and common optimization of designed.
Components• Each frame can be split in different panel.
• Don’t need to define the size of each panel as they are automatically scaled on a grid
Panel 2
Panel 1
Panel 3
Panel 4
Axes
The m-files
minigui.m (sets up the GUI):f1=frame('FEMLAB','size',[800 600]);
p1=panel;
p1.add(label('Rectangle width:'),1,1);
p1.add(label('Rectangle height:'),2,1);
p1.add(label('Circle center x:'),3,1);
etc.
p2=panel;
p2.add(label('Element size:'),1,1);
etc.
f1.get('geombutton').addActionListener('geommodel');
f1.get('meshbutton').addActionListener('meshmodel');
f1.get('solvebutton').addActionListener('solvemodel');
f1.get('plotbutton').addActionListener('plotmodel');
geommodel.m
(creates the geometry):function geommodel(event)
width=frame.get('width').getValue;
height=frame.get('height').getValue;
centerx=frame.get('centerx').getValue;
centery=frame.get('centery').getValue;
radius=frame.get('radius').getValue;
g1=rect2(width,height,'pos',{'0','0'});
g2=circ2(radius,'pos',{centerx,centery});
s.objs={g1,g2};
fem.draw=struct('s',s);
fem.geom=geomcsg(fem);
geomplot(fem);
3 cornerstones of Reaction Engineering
• Reaction kinetics– Evaluate it quickly
• Physical properties of reacting systems– Be accurate
• Modeling coupled phenomena– Stay organized