There are two requirements to consider when selecting an accelerometer for mechanical environment testing:
1) Select according to the purpose of use
a) Small mass or non-contact detection: For modal analysis of small structural parts, a small mass acceleration sensor needs to be selected to prevent the mass and connection stiffness of the sensor from affecting the dynamic characteristics of the measured structure. For some thin-walled structural parts For the study of resonance characteristics, it is recommended to use sensors with non-direct contact measurement.
b) Detection of low frequency and low acceleration: Low acceleration measurement under low frequency vibration requires the selection of an accelerometer with high sensitivity, and the signal-to-noise ratio of the accelerometer is required to be high. Otherwise, the noise at the measurement point will seriously interfere with the detection of the signal, or even submerge it. The signal being measured. High-sensitivity accelerometers are usually larger in size and heavier in mass. During use, special attention must be paid to the impact of the installation of the accelerometer on the vibration mode of the object being measured.
c) Detection of high-frequency and large acceleration: High-frequency vibration is usually accompanied by the amplitude of large acceleration, and a low-sensitivity accelerometer needs to be selected. For example, the detection of impact acceleration may reach tens of thousands of 8-value signals with frequencies of tens of kHz. During use, you need to pay attention to the frequency response characteristics, structural endurance, low-pass filtering range and other requirements of the accelerometer.
d) Measurement in high and low temperature environments: Measurements in high and low temperature environments need to consider the sensor’s adaptability to temperature. For example, the “heat” release characteristics of sensitive components will change its output parameters, and the high-temperature softening and low-temperature embrittlement of the connecting cable will affect its service life, output sensitivity, temperature response characteristics and stability.
e) Measurement in nuclear radiation environment: Nuclear radiation will cause radiation hardening of organic materials, temperature increase and other physical phenomena.
image, thus affecting the service life and sensitivity changes of the accelerometer.
f) General vibration acceleration measurement: General-purpose accelerometers should pay more attention to indicators such as flexibility of use, interchangeability, performance stability, lifespan, and reliability. The selection of comprehensive indicators such as sensitivity, dimensions, quality, and price is relatively moderate. market-oriented products.
2) Select according to the parameters to be measured
The accelerometer is selected according to the performance parameters of the vibration and impact test to be measured. The types of accelerometers vary. Taking the piezoelectric crystal acceleration sensor as an example, the following key parameters should be paid attention to when selecting:
*Measurement range of accelerometer
*Frequency response characteristics of accelerometer
*Structure form of accelerometer
*Additional mass effect caused by the accelerometer’s own mass
*The influence of the accelerometer bottom surface size on the mounting plane stiffness
*Temperature operating range of accelerometer
*Temperature effect on accelerometer sensitivity
*Repeatability of accelerometer measurement results
*Stability of accelerometer measurement results
*Accelerometer insensitivity to lateral vibration.