The experimental vibrational characterization of systems is one of the core competencies of the IDS. In addition to the necessary sensor equipment (accelerometers and force sensors), the institute also owns the hardware for a vibrational excitation with electrodynamic shakers as well as the corresponding systems for measurement data acquisition and processing.
Rotation Experiments
The ROT II test bench is used for experimental investigation of vibrations and rotational dynamics in rotating systems, particularly turbine blades. Operating in a vacuum and using precise excitation and measurement methods, it enables detailed analysis of vibration behavior under realistic conditions.
Acceleration Measurement Technology
One way of recording structural vibrations is to measure acceleration using accelerometers. Depending on the design of the sensor, a measuring range of approx. 500 g and a frequency range of approx. 1 Hz to 20 kHz can be covered.
The IDS has a large number of uniaxial sensors, that measure the acceleration normal to the surface of the structure, as well as triaxial sensors, which can measure the acceleration in all three spatial directions.
Data Collection and Analysis
The IDS owns various systems for recording and analyzing measurement data. Our portfolio includes different portable measuring systems with 8 to 88 measuring channels. The sampling rates are up to 204.8 kHz. The software solutions used for modal and operational vibration analyses is the M+P ANALYZER, as well as the M+P VIBCONTROL for vibration control. Our team is able to carry out further analyses in MATLAB if required.
Electrodynamic Shakers
The IDS is in possession of electrodynamic shakers of various sizes. These are used depending on the size and weight of the test object. Our range of modal shakers extends from 3 N to 2 kN dynamic nominal force. The large shakers in particular have an active cooling system and electronic position control, allowing tests to be carried out on objects the size of a small car. A frequency range from around 1 to 5000 Hz can be covered.
Experimental Modal Analysis
Experimental modal analysis covers various methods for characterizing the dynamic behaviour of vibrating systems using so-called modal parameters. For this purpose, the test object is usually stimulated externally under previously defined position conditions by a so-called modal hammer or electrodynamic shaker. The experimental modal analysis provides information about potentially critical frequency ranges and often serves as a supporting tool during the product development phase and for validating FE models. We have the necessary sensors, actuators, data acquisition and evaluation software in order to carry out an experimental modal analysis inside and outside of our laboratories.
Operational Vibration Analysis
The vibration analysis of a system under real operating conditions is referred to as an operational vibration analysis. Usually only the system's own excitation is considered here. In terms of measurement equipment and evaluation software, the requirements are similar to an experimental modal analysis. In order to ensure the real operating conditions, measurements at the machine's installation site are often essential. Our measuring systems are therefore all portable and also allow measurements outside the institute's own laboratories.
Force Measurement Technology
In order to measure dynamic forces, our Institute mainly utilizes sensors that make use of the piezoelectric effect. A typical application is measuring the excitation force of a shaker, e.g. as part of a modal analysis. Dynamic forces between less than 1 N and over 120 kN can be recorded.
Force sensors that operate with strain gauges are used to measure static forces. Based on the linear relationship between the acting force and the elastic deformation of the sensor, it is possible to draw conclusions about the force. We possess sensors for recording static forces of up to 1 kN.
Vibration Testing
As part of a vibration test, a characteristic excitation is applied that is typical for real operation in order to examine whether a component or assembly can withstand these loads long term. Vibration tests are therefore often part of approval processes. In general, for this purpose electrodynamic shakers and special software for force control are used. We have the necessary equipment to carry out vibration tests with dynamic forces of up to 2 kN if required.
Modal Analysis & Oscillation Control Equipment
- Various IEPE accelerometers from the manufacturers PCB and DYTRAN (uni- and triaxial)
- Various force sensors (IEPE and strain gauges) from the manufacturers PCB, DYTRAN and HBM
- Electrodynamic shakers from TIRA (S50303-M, S51130-MSC and TV50018) with 3 N - 2 kN nominal force
- M+P VIBRUNNER with 8 to 88 channels (204.8 kHz sampling frequency)
- M+P ANALYZER software for experimental modal analysis
- M+P VIBCONTROL software (incl. multi-axis option) for vibration testing
