The excitation of the random vibration test of the vibrating table (GB/T2423.56-2006) uses a random random input signal that includes all frequency components within the specified specification frequency range (wideband) at all times. Its instantaneous value obeys a normal (Gaussian) distribution. The distribution over the frequency range is represented by an acceleration spectral density (ASD) curve.
Random vibration is the most common type of stimulus that occurs in a real environment. It cannot be predicted in the past state in the future, and can only be predicted based on probability. In fact, these characteristics apply to most random vibration-related calculations such as fatigue and alternating stress.
Unlike the sinusoidal test, the random vibration of the vibration test rig during the duration is always excited by the resonance, although it does not reach the maximum. Most of the random signals in the laboratory have a 3 rms value, which means that the instantaneous value of the excitation over the test frequency range can be extended from zero to 3 times the total rms value (rms). The greater difference to be considered for random excitation is that there is a large amount of stress alternation between the zero crossings, both positive and negative. This property will affect fatigue damage and thus affect the life expectancy of failure.
Whether it is sinusoidal vibration or random vibration, only a better understanding of the production, transportation, use environment and the characteristics of the test equipment, you can more appropriately choose the right vibration method, so as to screen high-quality products and improve defective products. Performance
Cosmetic Bag,Travel Bag,Tote Bag,Shopping Bag
qiangcheng Industry and trade Co.ltd , https://www.qiangchenbag.com