Structure-borne sound sensor

from Wikipedia, the free encyclopedia

A structure-borne sound pick-up (structure-borne sound microphone) is an electroacoustic transducer for measuring structure-borne sound.

To measure the structure-borne noise, an analog electrical signal is generated from the mechanical vibration quantity with a sound transducer . This signal is then electrically amplified and, depending on the measurement task, frequency-weighted . The effective value is calculated from this and displayed with a measuring instrument .

Since it is very difficult to measure the sound field sizes inside solids , structure-borne sound measurements are mainly dependent on investigations of the vibrating surfaces. These vibrations can be recorded by movement, force or torque measurements, the most important parameters being the deflection or the vibration path, the vibration speed and the vibration acceleration. Accordingly, structure-borne sound sensors are classified into three basic types:

  1. Vibration accelerometer
  2. Vibration velocity transducer
  3. Displacement transducer

The knowledge of the oscillation path provides information about fatigue strength problems, aging, wear and danger moments. In other words, the oscillation path is proportional to the stress in the material. The vibration speed is used to assess the vibration quality (vibration intensity), smoothness, sensitivity to stimuli or annoyance to people. It provides criteria for the assessment of vibration damage to machines and buildings. The vibration acceleration enables the determination of the inertia forces, the assessment of building foundations and helps to solve special mechanical engineering problems. Knowledge of this variable is particularly advantageous where non-periodic vibrations occur. The acceleration a is proportional to the force F acting on the object . With the knock sensor of modern gasoline engines or with the timing machine , the time of the noise is of particular interest; the structure-borne sound sensor is used because one does not want to measure directly at the affected area (the clock does not have to be removed) or cannot (in the combustion chamber of the engine).

literature

  • DIN 45661, vibration measuring devices. Terms, parameters, disturbances.
  • DIN 45662, properties of vibration measuring devices, information in type sheets
  • L. Cremer, M. Heckl: Structure- borne sound . Springer-Verlag, Berlin 1996.

See also