As we all know, in the field of mechanical engineering and civil engineering, there are always various problems and challenges in the measurement of vibration characteristics. Although some vibration originates from the device or component itself, abnormal vibration caused by external forces or design tolerances can cause functional damage to the device or component. Therefore, the measurement and analysis of vibration characteristics are important measurement methods to identify and confirm the quality characteristics and working conditions of machines and components.
Acceleration sensors can usually be installed for relatively large objects to be measured, and the acceleration-velocity-displacement correlation measurement can be achieved by using the charge output signal of the acceleration sensor. However, when the mass of the measured object is relatively small and the measurement environment is more severe, the new non-contact, high-precision, real-time vibration measurement technology plays an important role. Among them, the laser pointer Doppler vibration measurement technology based on the principle of laser interference is currently the most important vibration measurement method that can obtain the best displacement and velocity resolution, and has been widely used in basic science and engineering measurement fields.
Represented by the German Polytec laser Doppler vibrometer, the high-end laser Doppler vibrometer has the following two main technical advantages: First, because this type of system uses laser as a detection method, there is no additional quality impact at all, and it has Intrusive, so that it can be measured on extremely small and extremely lightweight structures; secondly, this type of system can achieve micron/sub-micron amplitude resolution, high linearity, and in a very high frequency range (currently more than 1GHz ) And a considerable measuring distance range can still ensure the consistency of amplitude measurement.
In industrial research and development, laser Doppler vibrometers are not only used to study the dynamic and acoustic characteristics of different objects in mechanical engineering, acoustics, and other engineering disciplines and scientific fields. The research objects include automobile bodies, aircraft parts, various Large objects such as engines and buildings to tiny objects such as MEMS devices and data hard disk components can even measure heating objects, rotating surfaces, ultrasonic tools and complex and sensitive structures.
Take measurement in the acoustics industry as an example. In order to ensure that the generated musical instrument can produce beautiful and moving sounds, the green laser pointer Doppler vibrometer can judge the vocal quality of the musical instrument through vibration measurement as soon as possible; the laser vibrator can also be used for high-power speakers. It can be used to identify harmful diaphragm resonances that may occur in the system; even for more complex acoustic research, such as structural acoustic response (sound field) prediction, acoustic imaging and anti-sound research, etc.