Laser vibrometry is a non-contact optical vibration measurement by means of a laser beam and utilizing of the Doppler effect. A laser beam is emitted by the measuring system and subsquently reflected by the measured object as well as analyzed by the measuring system. Objetcts speed is determined based on the frequency shift of the laser beam. To ensure an optimum measurement result, the test specimen may need to be coated with a reflective spray paint or foil at the measuring points. The advantages of laser vibrometers are its high accuracy and frequency bandwidth as well as its fine three-dimensional resolution. A single measuring point corresponds approximately to the area of a small pinhead. The IDS has a large number of specialized laser vibrometers from the company POLYTEC, which we use for specific applications.
RoboVib
The RoboVib combines the 3D scanning vibrometer technology for vibration analysis with the advantages of a long-span Kuka industrial robot. This enables us to realize automated tests on complex and very large structures. ...
Scanning Vibrometer
A scanning vibrometer utilizes electronically adjustable mirrors that enable a redirection of the laser beam. This allows an object to be successivly measured in an automated programme sequence at any number of different measuring positions. This enables us to visualize vibration patterns, for example in order to investigate the operating vibrations of entire machines. The IDS owns three portable scanning vibrometers of the PSV-400 type with a bandwidth of 2.5 MHz and a resolution of 0.05 to 10 m/s. If required, the three scanning vibrometer can also be combined into a 3D system.
Micro System Analyzer
The Micro System Analyser MSA-100-3D is a 3D laser vibrometer especially developed for small structures and MEMS (microelectromechanical actuators and sensors). This means that structures the size of microchips can be analyzed regarding to their vibrational properties, whereby even amplitudes in the sub-picometre range can be resolved. The MSA-100-3D has an electrically movable cross table with a maximum displacement distance of 20x20 cm, which enables micrometreprecise positioning of the object under the sensor. Similar to the scanning vibrometer, entire surfaces of objects with a maximum size of approx. 10x10x15 cm can be measured. The bandwidth is 25 MHz.
Fibre-Optic Vibrometer
In a fibre optic vibrometer, the laser beam is split into two individual measuring beams by a beam splitter. This enables us to measure the relative speed of both measuring points. As a result, in-plane measurements can be realized, among other things. In-plane refers to the velocity components tangential to the surface of the element. The IDS owns two portable fibre-optic vibrometers of the type OFV-552 with a bandwidth and resolution of 2.5 MHz and 0.05 to 10 m/s.
Multipoint Vibrometer
The IDS owns a portable multipoint vibrometer of the type MPV-800 for capturing transient vibration processes, which can occur, for example, during the ramp-up process of aggregates. The MPV-800 enables the simultaneous measurement of up to 48 measuring points, spatially distributed over an area of any size. In addition, the scanning heads can be combined to form a 3D system with up to 16 channels, so that vibration measurements can be taken in all spatial directions at these 16 monitoring positions. The MPV-800 has a bandwidth of 100 kHz and a resolution of 0.001 to 1.75 m/s.
Derotator
For non-contact vibration measurement on rotating objects the IDS has a PSV-O-440 derotator. The derotator uses a rotating mirror system that can be synchronized with measurement objects rotational speed. This allows the laser beam to follow the rotation of the test specimen in a object-fixed, co-rotating reference system. This enables us to characterize the vibration of, for example, gear wheels or fans. The derotator works in conjunction with one of our PSV-400 scanning vibrometers and therefore has identical technical specifications. Speeds of up to 24,000 rpm can be covered.
Laser Vibrometry Equipment
- Polytec PSV-400 3D-Scanning Vibrometer (2,5 MHz option)
- Polytec OFV-552 Fiber-Optic Vibrometer (2,5 MHz option)
- Polytec MPV-800 48-channel Multipoint Vibrometer
- Polytec PSV-O-440 Derotator
- Polytec RoboVib with PSV-500 3D-Scanning Vibrometer
- Polytec MSA-100-3D Micro System Analyzer
