Frequency regulation function: in the frequency range of any frequency must be in (maximum acceleration & lt; 20g maximum amplitude & lt; 5mm) frequency sweep function: (on the frequency / frequency / time range) can be arbitrarily set the real standard back and forth sweeping frequency programmable function: 15 segments can be arbitrarily set for each segment (frequency / time) can be recycled Frequency function: 15 segments times the increase in the number of times, ①. ①. low to high frequency ②. high to low frequency ③. High to low frequency ③. Low to high and then to low frequency/circular Logarithmic function: ①. Down to up frequency ②. Upper to lower frequency (two modes of logarithmic/circular) Full-featured computer control: with LCD computer and printer (control, storage, recording, printing functions) (optional) Vibration test bench is used in the laboratory to simulate the effect of the real vibration environment of the test equipment, vibration test is in the vibration table using different input signals to stimulate the sample. Vibration test is mainly divided into sinusoidal and random vibration, due to the physical process of the two are different, there is no strict equivalence between the two, so in the selection of the test method, do not carry out sinusoidal to random severity level conversion.
Sinusoidal vibration tests use sinusoidal signals of fixed or varying frequency and amplitude, with only one frequency applied at each instant of time, under conditions that include a range of frequencies or a fixed frequency, amplitude, and test duration.
Sinusoidal vibration in real-world environments rarely occurs independently of vibration at a single frequency. This is true even when acceleration is measured directly on rotating machinery. For example, in gears and bearings, the actual tolerances and clearances that exist usually result in small variations in frequency. Some form of random vibration also occurs as a result of the random nature of rotating machinery.
Sinusoidal vibration can be described as deterministic motion, following definite laws, and it is perfectly possible to determine the future state at any specified time from the past state. In the course of sine-sweep testing, the method is often used to determine the moment of failure, because the failure is likely to be closely related to a specific frequency, and the effect of such correlation is not obvious with the random vibration test test method. Of course, sinusoidal test methods usually take longer to excite a failure than random test methods due to the fact that only a short period of time is applied at each *** vibration point during each frequency sweep. Although only one frequency is applied at any one time, if the sweep rate is slow enough, it is indeed possible to maximize the specific *** vibration peaks of the sample. It can also be used to detect potentially damaging *** vibration points, especially in design and development tests.
Another use of sinusoidal vibration tests is for dwell tests at the following frequencies:
A, known forcing frequency; B, resonant frequency of the sample Random vibration tests of shaking tables (GB/T2423.56-2006) are excited using an irregular, random input signal which at all times includes all frequency components within the frequency range of the specified specification (broadband). All frequency components. Its instantaneous values obey 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 excitation occurring in real environments. Its value at a future instant cannot be predicted in terms of past states and can only be predicted based on probability. In fact, these properties are applicable in most of the calculations related to random vibration such as fatigue and alternating stress.
Unlike a sinusoidal test, a vibration test stand always excites a resonance for random vibrations over a sustained period of time, albeit not to a maximum value. Most random signals in the laboratory have a root-mean-square value of three times, which means that the instantaneous value of excitation can extend from zero to three times the total root-mean-square value (r.m.s.) over the range of test frequencies. An even greater difference to consider for random excitation is the large amount of stress alternation, both positive and negative, that occurs between the over-zero crossings. This property will affect the fatigue damage and thus the life expectancy at which failure occurs.
Whether it is sinusoidal vibration, or random vibration, only a better understanding of the production, transportation, use of the environment and the properties of the test equipment, you can more appropriately choose their own vibration mode, so as to screen high-quality products, improve the performance of defective products.