Software for Operational
Modal Analysis
ARTeMIS |
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Frequently Asked Questions
How can I import data into ARTeMIS Extractor ?
There are three ways to do it:
SVS Configuration File, which is a text file with information about the
geometry, DOF information (nodal positions and directions of the measurement
channels) and links to the files containing the data.
Universal File Format (UFF). This is an alternative way to initialize a project.
Universal File Format is the industry standard format for file storage of
geometry, DOF information and measurements. We support both ASCII and binary
format.
OLE Automation. If you have an application that supports OLE Automation, like
Visual Basic, MATLAB, Excel, LabView, then the ARTeMIS Extractor has an OLE
interface called ARTX.Document that can be used to implement direct transfer of
geometry, DOF information and measurements from you own application.
Do I need any other software for ARTeMIS Modal
software? Ex.:MATLAB?
No, you only need the ARTeMIS Extractor to perform the
operational modal analysis.
The inputs to the program are data files, typically ascii files, a configuration
file (text file) where you specify the geometry and how the measurement are
linked to the geometry points.
If you don't want to write the configuration file using a text editor like e.g.
WordPad, then we have a software called ARTeMIS Testor that can put everything
together graphically using drag and drop. This software also allows you to
import data from many additional data file formats. Please follow this link for
more information: http://www.svibs.com/products/ARTeMIS_Testor/overview.htm
Optionally, if you have MATLAB you can start the ARTeMIS Extractor from an
m-file and initialize a project with data from the MATLAB workspace.
ARTeMIS Extractor supports MATLAB? Is it a Matlab
Toolbox?
All versions of ARTeMIS Extractor can be started from
MATLAB through an m-file provided by SVS. Through this m-file data stored in a
MATLAB structure can be transferred to an ARTeMIS Extractor project. The
technology that is used to accomplish this is the OLE Automation technique.
ARTeMIS Extractor is a Windows application and not a toolbox.
Is it possible to handle ambient measurement data with
SSI method in ARTeMIS Extractor or is it restricted to FDD?
All methods in the ARTeMIS Extractor software are
designed to do modal analysis using ambient response measurements. This is also
true for the three SSI methods that are included in the ARTeMIS Extractor Pro
version.
Can ARTeMIS Extractor perform system identification
under ambient vibration?
Since ARTeMIS Extractor is designed for extracting
modal parameters from response measurements, it is suitable for analyzing
measurements obtained from ambient vibration testing.
Can I use ARTeMIS Extractor to perform classical
structure testing, such as those with knowing excitation force? Is there any
limitation for number of channels?
ARTeMIS Extractor is only for modal analysis based on
measured responses. If known excitation forces are used the software can still
be used to analyze the responses. However, the excitation itself cannot be taken
into account, which means that the mode shapes always will be unscaled.
The software has been tested with 350 channels measured simultaneously at 12.5
kHz for 90 seconds. If more measurement channels are needed it is recommended to
split the measurements into more data sets keeping a few sensors at fixed
reference positions.
Can I use National Instruments' front end?
As long as your front end can save the data in text
file format, such as DaisyLab format, MATLAB ascii file format or universal file
format, then you can use any front end.
How is the mode shapes expressed in the output file?
What means: NODE / X-ABS / X-ANG / Y-ABS / Y-ANG / Z-ABS / Z-ANG in the SVS
format?
First of all: All mode shapes exported from ARTeMIS
Extractor are complex. In the SVS Format the modes are exported in the following
format:
NODE / X-ABS / X-ANG / Y-ABS / Y-ANG / Z-ABS / Z-ANG
which means that the first number is the node number. The second and third are
the absolute
value and phase angle (in radian) of the x-coordinate. Then it follows the
absolute value and
phase angle of the y-coordinate, and so on. When you have the absolute value and
the
phase angle you can construct the full complex number.
In the Universal File Format data set 55 the complex modes are exported as real
and imaginary
parts instead.
For a complete description of the two formats please consult the on-line help
under the following
topic: Using ARTeMIS Extractor -> Working Across Projects -> Exporting Modal
Results
Is ARTeMIS suitable for analyzing composite concrete
plates (beams, cylinders, tanks shapes) with different layer densities and
reinforcement in both 2D and 3D?
Yes our software is capable of returning the modes of
composite structures and structures of anisotropic material. What is important
is that you measure in enough measurement points and cover all directions. Also,
if the structures have sub elements that you like to know the local modes of, it
is vital that you put measurements sensors on such structures as well.
Is the software also suited for predictive analysis,
i.e. if we input the structure shapes and material properties and apply a force
at a point it will predict the Hz and velocity at points of interest?
No, ARTeMIS Extractor is designed to extract modal
parameters from experimental data.
Is Finite Element modeling performed inside our
software or has it to be performed on a separate software?
FE modeling is not performed inside our software. We
recommend FEMtools for finite element updating based on results from ARTeMIS.
Is our software compatible with other software like
PRO-E, ANSYS, etc.?
If these software packages have a FE updating facility
where modes can be imported through Universal File Format, then it is
compatible. This is the case with FEMtools.
If the customer decides not to renew the annual service
agreement, does the software keep running or is it disabled?
The software keeps running no matter if the customer
renew service or not. What runs out is our support and future updates of the
product.
Can I transport the software to multiple computers or
is the license tied to a single machine?
The license system is based on online activation using
an activation key. The activation key they purchase allows them to activate the
software 1 time, which essentially means installation on 1 PC.
Which is the data input facilities existing on Artemis?
We support many different file formats for data import.
We prefer time series input and are here supporting the following formats:
> ASCII File Format (*.asc)
> SVS Binary File Format (*.bin)
> ASCII Universal File Format (*.uff or *.unv)
> Binary Universal File Format (*.uff or *.unv)
> TEAC Header File Format (*.hdr)
> GeoSIG Header File Format (*.ghf)
> Diadem Header File Format (*.dat)
> Kyowa Header File Format (*.csv)
> Kinemetrics Altus File Format (*.evt)
> Wave File Format (*.wav)
Please contact us if you need other kind of data file formats. We will do our
best to implement it.
What sort of field data need to be obtained in order to
use your software?
The input field data required for the software are time
series measurements of the vibrations, usually obtained using accelerometers.
You should be able to provide several channels measured simultaneously in order
to obtain the highest quality of the estimates.
What is the basic principle by which the ARTeMIS
software is calculating the modal parameters?
The basic principle is to import raw time histories of
measured responses, taken in all the points where the mode shapes are required.
Also required is geometrical information about the test geometry as well as
where on the test geometry the measurements are taken. The raw measurements are
then processed in various ways, so that the modal parameters can be extracted
using up to six different techniques that finally can be compared and validated
before export.
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