ARTeMIS Modal Product Information



Do you need to do modal analysis without controlling the input?

ARTeMIS Modal is a powerful and versatile tool for Operational Modal Analysis. Its ability to produce validated modal parameter estimates, based on parallel analysis of up to eight different analysis techniques, makes it the natural choice in mission critical applications.

From the patented Frequency Domain Decomposition (FDD) techniques to the unique Crystal Clear Stochastic Subspace Identification (SSI) techniques, ARTeMIS Modal enable engineers to obtain validated estimates the mode shapes, natural frequencies and damping ratios, directly from the raw measured time series data of structures under natural conditions.

The software is designed for the vast number of cases where it is preferred not to control or measure the loading.The software is used by engineers all over the world for modal analysis of all kinds of structures:

  • Operating machinery or other mechanical structures with or without rotating components.
  • Large civil engineering structures like bridges, dams and buildings subjected to ambient loads.
  • Structures with rotating components such as wind turbines, stream turbines, engines and gas compressors.
  • Maritime structures like ships and offshore structures.
  • Automotive, trucks, trains and vehicles and sub parts systems.
  • Aerospace structures such as launch vehicles and aircrafts.
  • The software is an open, and user friendly platform for modal testing, modal analysis and modal problem solving. If you can measure the vibrations, ARTeMIS Modal can give you the modes in terms of mode shape, natural frequency and damping ratio.
  • In-situ testing of a structure – True boundaries.
  • Natural environment – True excitation forces even in the presence of deterministic signals (harmonics).
  • Test during normal service state – No interruption needed - increased productivity.
  • Use operational forces - No artificial excitation needed.
  • Modal parameter results describes the true service state of the structure.
  • Can be used on extremely small or large structures – size does not matter.
  • Scalable software – Unlimited amount of sensors and data points.
  • Handles multiple test setups (rowing sensors) and multiple reference points for increased mode shape accuracy.
  • Fast and automatic results – Saves time.
  • User friendly – Have your first modal parameters estimated in a matter of minutes. 
  • Versatile – If you can measure the vibration – ARTeMIS will always give you the answer.
  • Open - Major data input file formats supported.
  • Outstanding results – Validated output based on several parallel modal analysis – Accuracy.
  • Results can directly be used by e.g. FE updating software solutions.

ARTeMIS Modal is produced in three versions and the key features are listed below. All versions have estimators for Operational Modal Analysis (OMA), Experimental Modal Analysis (EMA) and Operating Deflection Shapes (ODS). As optional feature for all versions is the Data Acquisition plugin, allowing direct control of selected data acquisition hardware.


ARTeMIS Modal Basic

This is the basic version having a frequency domain method for Operational Modal Analysis. Specifically it contains the following tasks and features:

  • Prepare Geometry Task.
    • Import/modify existing geometry.
    • Create geometry from scratch using interactive tools.
  • Manage Measurements Task.
    • Import/merge measurements file into single or multiple test setups.
    • View imported measurements channel by channel.
    • Edit imported measurements. Truncation, differentiation or integration.
    • Connect/disconnect channels and Test Setups.
  • Assign DOF Information Task.
    • Link channels with geometry nodes and directions.
    • Link using drag-and-drop or by direct editing.
    • Automatic identification of reference channels.
  • Prepare Data Task.
    • Configure all preprocessing of measurements.
    • Repair measurements having severe outliers.
    • View processed data of channels and Test Setups.
    • Compare processed data of reference channels.
  • Estimation Task.
  • Report Task.
    • Easy selection of graphics and tables.
    • Seamless integration - Microsoft® Office 2000, XP, 2003, 2007, 2010 and 2016 32bit/64bit.
    • Generate Word documents and Power Point presentations.
    • Predefined standard templates.

ARTeMIS Modal Standard

This is the mid-size version having three frequency domain methods for operational modal analysis. Besides all the tasks and features of the Basic version above, this version has the following additional tasks and features:

  • Prepare Data Task.
  • Estimation Task.
  • Validation Task.
    • Overlaid mode shapes animation.
    • Mode shapes difference animation.
    • Mode shapes side-by-side / top-bottom animation.
    • Modal Assurance Criterion.
    • Comparison between estimated and imported modes.
    • Frequency versus Damping diagrams.

ARTeMIS Modal Pro

The ultimate tool having all the features developed over the last two decades. It has up to eight operational modal analysis methods and supports several plugins for e.g. automatic file upload, automatic modal estimation and damage detection. Besides all the tasks and features of the Basic and Standard versions above, this version has the following additional tasks and features:

  • Prepare Data Task.
    • Peak Reduction. Reduce or eliminate harmonic peaks and/or unwanted modes.
  • Estimation Task.
  • Optional Plugin Modules for Structural Health Monitoring.
    • Data Manager Base Module including Historical Measurement Statistics and 3D Data View.
    • Damage Detection, Classic and Robust methods as well as unifying Hotelling Control Chart.
    • Modal Parameter History including automatic mode tracking and tracked modes export.
    • Interstorey Drift Analysis. Estimation of relative interstorey drift in multiple locations.
    • Automatic File Upload. Upload files automatically from a designated folder and optionally perform modal analysis and damage detection.

With our flexible upgrade policy you can get started in an affordable way, and then upgrade whenever needed.

Frequency Domain Decomposition

ARTeMIS Modal includes up to three frequency domain modal analysis techniques derived from the patented Frequency Domain Decomposition technology utilizing the singular value decomposition of the estimated spectral densities of the measured response. The techniques available are:

  • Frequency Domain Decompostion - FDD.
  • Enhanced Frequency Domain Decompostion - EFDD.
  • Curve-fit Frequency Domain Decompostion - CFDD.

All three techniques are based on peak-picking in the frequency domain using either automatic picking or manual picking using the mouse. Once picked, the mode shapes are ready for immediate animation. The techniques are all specially designed to account for the presence of deterministic signals (harmonics) in case of rotating structural parts or other sinusoidal excitation.


Benefits

  • Intuitive modal parameter estimation based on peak-picking in frequency domain.
  • Immediate results even in case of hundreds of measurement channels and modes.
  • Extremely robust being based on the Singular Value Decomposition of spectral densities.
  • Handles single or multiple Test Setups in exact same way.
  • Through the use of the powerful harmonics detection modal parameters can be extracted in the presence of harmonic components from e.g. rotating machinery.
  • Peak-picking can be made manually or automatic.
  • EFDD and CFDD methods provide estimates of damping ratios as well as improved estimates of natural frequencies and mode shapes.

Stochastic Subspace Identification

ARTeMIS Modal Pro includes up to five time domain modal analysis techniques. They are all of the data driven Stochastic Subspace Identification (SSI) type and all implementing the powerful Crystal Clear SSI feature. This feature result in extremely clear stabilization diagrams with un-seen accuracy of the physical parameters and nearly no noise modes.  The techniques available are:

  • Extended Unweighted Principal Component - SSI-UPCX.
  • Unweighted Principal Component - SSI-UPC.
  • Principal Component - SSI-PC.
  • Canonical Variate Analysis - SSI-CVA.
  • Unweighted Principal Component Merged Test Setups - SSI-UPC-Merged.

These techniques estimate the modal parameters directly from the raw measured time series. The SSI techniques incorporate effective ways of dealing with noise. As a result, the modal parameter estimations are the most accurate commercially available today. The SSI techniques can work with closely space and repeated modes with light or heavy damping. Since they are working in time domain there are no leakage bias or lack of frequency resolution, see below. As a result, the modal parameter estimates are asymptotically unbiased. Further, as the SSI techniques are low model order estimators, the statistical errors of the modal parameter estimates are extremely small.


Features

  • Modal parameter estimation based on estimation of state space models in time domain.
  • State space model estimation can be done on even large channel counts through the use of Projection Channels.
  • Projection Channels can be found manually, semi-automatic or fully automatic.
  • Very fast estimation of even hundreds of models of increasing dimension.
  • Very limited user interaction required. Can be fully automated. By default, the techniques always start with an fully automatic estimation of the global modes.
  • Unbiased modal parameter estimation using standard least-squares or the Crystal Clear SSI® solver.
  • Estimation of uncertainties of extracted modal parameters (SSI-UPCX).
  • Handles single or multiple Test Setups.
  • Modal parameters can be extracted in the presence of deterministic (harmonic) signals from e.g. rotating machinery.
  • Extraction of global mode estimates can be made manually or automatic.
  • Estimated state space models can be validated against data in frequency domain. Both spectral response and prediction errors can be validated.
  • Estimated state space models as well as the entire stabilization diagram can be exported in ASCII file format for use outside ARTeMIS Modal.
  • All SSI methods are available in the ARTeMIS Modal Pro version.

Benefits

  • Unbiased estimation – No systematic estimation errors. No leakage – The SSI techniques work in time domain and are data-driven methods. Since the model estimation is not relying on any Fourier transformations to frequency domain no leakage is introduced. Leakage is always introduced when applying the Fourier transformation and assuming periodicity. Leakage always results in an unpredictable overestimation of the damping. No problems with deterministic signals (harmonics) – Since the modal parameters are extracted directly by fitting parameters to the raw measured time histories, the presence of deterministic signals, such as harmonics introduced by rotating machinery, does not create problems. Harmonics are just estimated as very lightly damped modes. This is in contrast to frequency domain methods relying on the estimation of half power spectral densities that all assume that the excitation is broad-banded (white noise). Using these methods in presence of deterministic signals introduce bias in the modal parameter estimation.
  • Less random errors. Low-order model estimator - SSI algorithms are born linear least-squares fitting techniques fitting state space systems with correct noise modeling. This leads to the use of much smaller model orders than other commercially available high order model estimators. These estimators are often used to approximate a non-linear least squares problem with a linear least-squares fitting problem. This is an often seen approximation when fitting e.g. polynomial matrix fractions. In order for this approximation to work, a high-order polynomial order is needed. Since this leads to the use of many parameters compared to a low-order technique, the uncertainties of the high-order parameter estimates becomes larger. More parameters are fitted with the same amount of data available, meaning less independent information per estimated parameter. All modal parameters are fitted in one operation. All parameters fitted are taking advantage of the noise cancellation techniques of the orthogonal projection of SSI. Other commercially available methods often fit the poles (frequency and damping) first, and then use the noisy spectral data and the estimated poles to fit the mode shapes resulting in poor mode shape estimates.
  • Automatic Mode Estimation. All SSI techniques includes automatic mode estimation that searches the stable modes in the SSI Stabilization Diagram. All stable modes of all estimated models of all test setups are included in the search, and the result is modal estimates of natural frequencies, damping ratios and modes shapes of high accuracy. The estimates are presented in terms of both mean values and standard deviations. Even in the case of closely spaced or repeated modes and multiple test setups, the automatic mode estimation for SSI works.
  • Estimation of Modal Uncertainties. Modal estimation methods that make use of Stabilization Diagrams only present, in general, the estimated mean values of the modal parameters. Typically, Stabilization Diagrams show the mean values of the natural frequencies of the estimated modes with respect to selected model dimensions. In a diagram like this, the search for stable modes is made on the basis of the mean values. Even if the stabilization is clear, it is still difficult to assess the level of confidence that can be associated with each of the presented modes. In the SSI-UPCX technique it is possible to visualize the uncertainty of the individual estimates in terms of confidence bounds around the mean values. These uncertainties are taken into account when estimating the global modes in SSI-UPCX.

ARTeMIS Modal includes time as well as frequency domain Operating Deflection Shapes (ODS). These features allow you to study the overall vibration pattern either over a time segment or at a specific frequency.

ODS analysis is very beneficial in combination with Operational Modal Analysis as it determines and visualizes the combination of the actual forcing functions acting on the structure and the dynamic behavior of the structure. Results can be shown as displacement, velocity or acceleration in SI, Imperial or user-defined units (Time Domain ODS). Decimation and various filters (low-pass, band-pass, band-stop and high-pass) can be applied to frequency limit the analysis.

Both time and frequency domain ODS are available in all versions of ARTeMIS Modal.

Frequency Domain Operating Deflection Shapes

Benefits

  • Frequency domain animation of all test setups using multiple reference estimation.
  • Unscaled or scaled animation with respect to a specific reference channel.
  • Pick a frequency to animate the shape on various spectral diagrams or time-frequency spectrograms.
  • View the animation as a movie or step through the movement, frequency step by frequency step.
  • Store shapes for specific frequencies in a Shapes list.
  • The measurements can be signal processed using the same Signal Processing Control dialog as used by the modal analysis techniques.
  • AVI movie creation of animations.

Time Domain Operating Deflection Shapes

Benefits

  • Time domain animation test setup by test setup of all frequency content in the processed data./li>
  • Animation can be made in displacements, velocities or accelerations. Integration filter can be configure by the user.
  • Pick a segment in time to animate.
  • View the animation as a movie or step through the movement, time step by time step.
  • AVI movie creation of animations.

In ARTeMIS  Modal estimated modes can be validated by comparing modal results from the different estimation techniques used for the same project. Results of different projects can also be compared, allowing an older analysis of a structure to be compared with a new analysis. External results may also be imported using Universal File Format, allowing e.g.  numerical modes of a Finite Element model to be compared with experimentally obtained modes.


Features

  • Overlaid animation of mode shapes.
  • Difference animation of mode shapes.
  • Side-by-side and Top-Bottom animation of mode shapes.
  • 3D and table read-out of the Modal Assurance Criterion (MAC).
  • Mode shape Complexity Diagram.
  • Frequency versus Damping Diagram, with optional uncertainty ellipsoids in case of SSI-UPCX.