Analysis of Solid Body Oscillations
Our equipment allows us to perform the following tasks in the domain of solid body oscillations:
- One- to three-dimensional measurement of oscillations using non-contact laser vibrometry or acceleration sensors (contacting)
- One- to three-dimensional vibration measurement at several points using laser vibrometry or acceleration sensors, along with analysis and animation of the results
- Measurement of stationary and intermittent oscillations, e.g. for the analysis of transient-state behavior
- Operational vibration analysis ("operational Modal Analysis", OMA) with up to 15 channels
- Experimental modal analysis (EMA) with any number of channels
Vibration Measurement/Modal Analysis
For vibration measurements, in particular experimental modal analysis, we at MuD use LMS Test.Lab Software with the front-end Scadas III.
We therefore have complete solutions on-site for engineering in the test area, offering data collection in high speed and on up to 12 channels simultaneously, of which any channel can be evaluated as desired.
Test.Lab provides numerous tools for testing, analysis and providing data reports. We offer a complete portfolio, including solutions for rotating machines, structural and acoustic tests, testing under different environmental conditions, vibration analysis and evaluation, reporting, and data administration.
To produce experimental vibrations, we have the following possibilities:
- electromagnetic shakers of various performance classes,
- piezo actuators of different designs, in particular for high forces and/or high frequencies,
- impact hammers for modal testing within different frequency ranges.
Acoustic Measurements
Our activities in the area of vibration measurement technology are also closely connected to the area of acoustics. For acoustic measurement in gases, we use high-quality measuring technology from the company Brüel & Kjaer. Different microphones of the types 4138 and 4189 are used, with which we can create almost any spatial sensor configurations, from simple measurements based on A/B or X/Y principles (stereo), to complex acoustic array fields based on the beamforming (spatial filtering) approach. Our measurement equipment is supplemented by a sound level meter, type B&K Mediator 2238, which can be used together with our other equipment both for simple approximations as well as for precise measurements.
In addition to acoustic measurement in gases, we are interested in sound field analysis and visualization in transparent media (e.g. liquids, plexiglass, air). To ensure non-repercussive visualization, we use the procedure outlined by Zipser. This procedure enables a planar, large-surface measurement of a sound field with the help of a scanning laser vibrometer. The laser is sent through a sound field and focused on a rigid reflector. Due to pressure changes caused by the sound wave, the refraction index of the medium changes. This leads to a change in the optical path length and can be measured by the vibrometer. As an example, this procedure can be used for the measurement of ultrasonic fields.
Vibration exciter
Several electrodynamic shakers are available for the excitation of vibrations within the scope of vibration analysis. With the air-cooled vibration test system from Spectral Dynamics from the "Air Cooled" series shown in the pictures, masses of up to 250 kg total weight can be subjected to an acceleration of up to 100 g and at frequencies of up to 3000 Hz.