Product News

Casestudy HGL - OMA on Rotating Machinery.  

The HGL Rotational ODS+OMA system is a Software & Hardware solution which determines the modal values (natural frequencies, damping and mode shapes) of rotating parts under operating conditions. In order to obtain these measurements, one or more vibration transducers that rotate with the shaft and a high precision phase related speed signal are required. The transfer of the vibration signals can either be done by telemetry or slip rings.The identification of the modal values is processed by the Operational Modal Analysis Software (OMA) named ARTeMIS Extractor.

• Brake Disc Assembly
• Wind Turbines
• Diesel Engines
• Gas Turbines
• Industrial Fans
• Ship Transmissions
• Ship Propellers

• Test Benches
• Laboratory
• Test Cells
• Balancing machines
• Dynamometers
• Rolling Roads
• Wind Tunnels

HGL Rotational OMA + ODS
The HGL-Rotational OMA+ODS System is especially designed and developed to perform structural testing of rotating parts whilst in running mode. Next to the classic Operation Deflection Shape method (ODS) it‘s now possible to evaluate the modal values (natural frequencies, damping and mode shapes) by using Operational Modal Analysis algorithms (OMA). The vibration measurements are done by transducers which are mounted on the rotating shaft. As the rotational movement is measured by a tacho probe, the position of the rotating transducers can be accurately calculated at any time. Knowing the actual transducer position allows to generate signal blocks for pre-defined angle positions. This signal blocks can be transferred to ODS calculations in HGL ODS or to use the OMA software ARTeMIS Extractor to identify the modal values.

HGL Rotational OMA
The HGL-Rotational OMA Module can generate complete data sets for the operational modal analysis software ARTeMIS Extractor, again under the assumption that channel assignment is known. This data sets contains:
• Wire frame model geometry by points, lines and surfaces,
• The channel assignment for each measurement,
• The vibration data as time series.

This data sets can directly be transferred to the ARTeMIS Extractor. Using the Data Organizer in ARTeMIS Extractor, it is possible the check the transferred data at any time. For the estimation of the modal values all known algorithms offered by ARTeMIS Extractor are available:

• FDD (Frequency Domain Decomposition),
• EFDD(Enhanced FDD),
• SSI (Stochastic Subspace Identification).

The calculated modal values can be listed charts; mode shapes can be animated by an extensive animation module. In addition to this, ARTeMIS Extractor offers various tools to validate the modal data:

• Overlay of mode shapes,
• Stabilization plots,
• Modal Assurance Criteria (MAC).

Using HGL-Rotational OMA it is now possible to identify the modal values of a non linear system dependent on operating parameters. Examination on brake discs have shown that with HGL Rotational OMA the influence of pressure in the brake calliper on the modal values natural frequency and damping can be simply evaluated. By using the automatic analysis tools of ARTeMIS Extractor the modal values of the brake system can be shown as function of brake pressure.

You can try it on your own by downloading a one month trial version of ARTeMIS Extractor Pro Release 5.3.


Next Conference

Meet us at the EURODYN conference in Leuven, Belgium from 4 to 6 July 2011.

Also, we will exhibit at the EVACES conference in Varenna, Italy from 3 to 5 October 2011.

On both conferences we will demonstrate the new, ultrafast Crystal Clear SSI in the newly released ARTeMIS 5.3.

New Course in ARTeMIS This Fall

This 2-day course is for the new as well as experienced users who want to be updated on Operational Modal Analysis technology as well as the latest features of ARTeMIS Extractor 2011.

The course will be held on October 27 and 28, 2011 at Sana Rex Hotel in Lisboa, Portugal. There will be lunch and coffee breaks during the day and free WiFi internet access. The course instructor is Dr. Palle Andersen, CEO and and senior developer of ARTeMIS Extractor. More info will follow.

Attending the course will cost 500 € per person and of course we give a 50% student discount.

Sign up:
Please send an email to Gloria Martins at with Name, Title, Address, Company/Institution and number of participants. We need your registration no later than October 3, 2011.