Modal Testing and Modal Analysis - SIMO, MIMO, and ODS

Effective and affordable modal testing and analysis solution for SIMO, MIMO, and ODS testing methods. The modal test is an indispensable tool to determine natural frequencies and mode shapes of any structure. With our solution, you are able to excite the structure with an impact hammer or modal vibration shakers and easily measure the responses. Import or draw your geometry for rich visualization and animation of your structures.

Modal Analysis and Modal Testing - ODS, MIMO, OMA solution from Dewesoft
IEPE
IEPE
Charge
Charge
Voltage
Voltage
Strain / Stress
Strain / Stress
Acceleration
Acceleration
Velocity
Velocity
Displacement
Displacement
Video
Video
High-speed video
High-speed video

Main Features

  • IMPACT HAMMER OPERATION MODE: Allows grouping, rejecting, and repeating measurement points; multiple references and excitation points are supported. The ability to move excitation and response points is giving the user full flexibility when performing measurements.
  • MULTIPLE SHAKER OPERATION MODE: In combination with the built-in function generator module, the system allows burst, sine sweep, and random noise excitation. The user can also excite the structure with externally driven shakers.
  • ADVANCED MATH: Mode indicator functions (MIF), H1, and H2 estimators, power spectral density (PSD) are fully implemented in Dewesoft and can be used in combination with other maths.
  • RICH VISUALIZATION: Animation of a structure in all three directions and with different projections is available during the measurement. This functionality is a great tool to determine the quality of results, giving the user a chance to repeat the measurement of any point. The modal circle tool determines exact resonance and calculates viscous or structural damping factor.
  • GEOMETRY UNV IMPORT/EXPORT: Geometry can be either built via a built-in geometry editor or imported via the UNV file. Users can also save geometry in the UNV file and open it in external software.
  • DATA EXPORT: All data, from the raw time domain to FRF's, can be exported to various different formats, including standard UNV file format.
  • LIFETIME FREE SOFTWARE UPGRADES AND SUPPORT: Our data acquisition systems come bundled with award-winning Dewesoft X data acquisition software. The software package is always evolving and new features are being added. We offer lifetime FREE software upgrades and technical support to all our users.

Multi-input Multi-output (MIMO) calculation

MIMO measurement techniques are a well-proven and well-established method for collecting FRF data sets. They offer some distinct advantages for the measurement and extraction of basic modal parameters especially while testing larger structures. 

The main advantage of MIMO is that the input-force energy is distributed over more locations on the structure. This provides a more uniform vibration response over the structure, especially in cases of large and complex structures and structures with heavy damping. 

Excitation in more locations often also provides a better representation of the excitation forces that the structure experiences during real-life operation.

Multi-input Multi-output (MIMO) calculation

Easy and Quick Setup

In the case of a high number of measured channels, adding and removing the excitation and response channels is a very simple process with autofill setup.

Autofill functionality is enabled for:

  • Autofill for uniaxial and triaxial sensors (response channels)
  • Start node index and index increment selection
  • Define the direction and sign of added channels
  • Group the sensors and define the number of groups
Easy and Quick Setup

Auto-generated Visualisation Screens

For an easier start, Dewesoft X software offers auto-generated displays for modal analysis. The predefined displays already come with the most often used instruments and an arrangement that makes sense according to the modal testing. 

One screen is generated for the acquisition and measurement process and the second screen is defined for the post-analysis of the measured data.

Of course, the flexibility of Dewesoft X data acquisition software allows you to easily change and customise the default displays or define unlimited news ones.

Auto-generated Visualisation Screens

Structure Geometry Animation and Projection

Inside Dewesoft X DAQ software, you can quickly draw simple 3D structures as well as import more complex ones using UNV file format. The cartesian and cylindrical coordinate system is supported, which is great for drawing circular objects.

You can animate the structure at a single frequency in all three directions. During the measurement, the color of the points is changing, for easier identification of the excitation point and the response points.

The structure can be shown in different projections:

  • 3D perspective,
  • 3D orthographic and
  • several 2D projections.
Structure Geometry Animation and Projection

Merge Multiple Data Files Together

Dewesoft X software makes it very easy to record one data file for each point or group in your subject under the modal test.

After the measurements are done you can easily merge separate data files into one to analyze and animate the structure and observe the behavior.

Each transfer function contains information about response node, response direction, reference node and reference direction.

 

Merge Multiple Data Files Together

Operating Deflection Shapes (ODS)

In ODS analysis the structure is only excited by the machine, like in real operation, whenever it is not possible to vary the excitation frequency. ODS is the simplest way to see how a machine or structure moves during its operation, at a specific frequency.

Inside Dewesoft X software modal test module, one of the acceleration sensors has to be defined as excitation (this one is the reference, normalized to 1), and others as a response. Animation can be displayed as usual but only makes sense in areas with good coherence.

Operating Deflection Shapes (ODS)

Exporting Data

After the measurement is done the data can be exported to a lot of different file formats, e.g. UNV/UFF, Diadem, Matlab, Excel, Text... The transfer function can be separately exported by Real, Imag, Ampl or Phase part.

The Universal File Format (also known as UFF or UNV format) is very common in modal analysis. Depending on the header, it can contain either transfer functions, coherence, geometry, ... or various other data. We modified the  UNV/UFF export, especially for the modal test.

See the complete list of supported export file formats.

Exporting Data

OMA - Operational Modal Analysis

The operational modal analysis is used for large civil engineering structures, operating machinery, or other structures, making use of their output response only. These structures are always loaded by natural loads that cannot easily be controlled and measured, for instance, wave load (offshore structures), the wind loads (buildings), or traffic loads (bridges).

Dewesoft X can be used to perform all the necessary time-domain measurements which can be exported to various file formats in order to make calculations in external software (e.g. ME'scope).

OMA - Operational Modal Analysis

Advanced Modal Analysis

With the direct export option of your measured data to ME‚Äôscope modal analysis software, you can use advanced post-processing algorithms to analyze the data.

Advanced Modal Analysis

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