Modal Analysis | vModal

Modal analysis and operating deflection shapes


The Modal Analysis is a very powerful tool for the determination of the dynamic behaviours of a mechanical structure. The new vibration measurement technology it is possible to all measurement within a reasonable time frame. If a modal hammer or a shaker is used for the excitation is dependent from the size and the nature of the test object. The analysis of the measurement data can be done without the measuremenst system in the office.

Modal analyse

No engineer could possibly manage to design a construction, solving all problems due to noise and vibrations without precise knowledge of the inherent properties of a structure. To determine the structure’s properties experimentally the modal analysis offers an excellent tool. The modal analysis provides the engineer with the complete hard- and software equipment necessary to carry out a successful modal analysis or an operating deflection measurement.

Structure Analysis

The multichannel FFT analyser is integrated in the VL modal system. It is also a stand alone analyser. The analyser uses PC boards, providing 2 to 32 channels. It is a complete noise and vibration measurement system. Up to 4 Channels a USB-Box solution is available.

UFF Import

Data from external DAQ systems can be imported as file in the UFF format.

External Analysis

Via IEEE interface a data import from several external analysers, such as B&K, HP or ONO-SOKKI, is possible. For the Transfer we use the USB / IEEE interface from National Instruments.

Measurement data

Every measurement will be transferred via the measurement interface to the database. From there they may be recalled for any displaying and editing. Further the measurement interface includes the routines for modal extractions of multi-shaker measurements.

Modal analysis

To determine the eigen-values functions are available as listed below:

SDOF local, global

MDOF, local, global


Mode-indicator function

Poly reference

Synthetic frequency response functions

Fit quality function

MAC function


Using the results of the modal analysis, eigen-values and vectors, the engineer will be able to create a mathematical model, suitable for any calculation concerning sensitivity and optimizing. A feature to carry out forced response calculations is also integrated. Any verification of the FEM calculation is possible with a special import module for FEM eigen-vectors.

Operating Deflections

Stationary operating deflections can be measured in the frequency or time domain. For instationary deflections, measurements in the time domain can be done.


All results may be displayed as animated shapes. There are wire frame and hidden lines models that enable the user to display the results of the operating deflection measurements, the modal analysis or the calculated forced response vibrations.

Show modul

Results can be passed on with the free copiable showmodul. The receiver can see and print the measurment data as well as the animated deflection shapes.