Admittance method

Shenzhen Shenchuang Hi-tech Electronics Co., Ltd(SChitec) is a high tech enterprise which specialized in phone accessories production and sales. Our main products include travel chargers, car chargers, USB cables, power banks and other digital products.All products are safe and reliable, with unique styles.products pass certificates like CE,FCC,ROHS,UL,PSE,C-Tick,etc,  If you are interested in, you can contact ceo@schitec.com directly.

Stay Charging Safely with SChitec

Admittance method

Mechanical admittance is a characteristic parameter of the system in frequency domain (see mechanical impedance). The natural frequencies of large and complex structures are numerous and dense, and the vibration modes are very complex, which can not be measured by simple methods. However, the response of the system to the excitation force can be tested first to obtain the mechanical admittance, and then the modal parameters or physical parameters can be determined by graphical identification (i.e. amplitude frequency, phase frequency, real frequency, virtual frequency or vector terminal diagram of the mechanical admittance) or computer identification.

Time domain identification

The modal parameters of the system can be obtained directly by using the time history of vibration. For free vibration, the modal parameters can be calculated directly by the relationship between free vibration and impulse response function (one of the time-domain characteristic parameters of the system, whose Fourier transform is mechanical admittance). For forced vibration, the modal parameters can be calculated by digital time series analysis method or other methods (such as random decrement method, filtering method, etc.). The advantage of time domain identification method is that it can make use of the vibration signal of the machine in the running state, which is suitable for large-scale structures that can not be tested in the laboratory; the disadvantage is that the excitation force of natural vibration source is often unable to be measured and controlled, but can only be identified by the response value, so the accuracy is low.

Load identification

It refers to the analysis and determination of the nature of the vibration source (is it regular or random? Is it fixed force or fixed motion?...) , propagation path and load spectrum (i.e. time history of load) imposed by vibration source on the system. Load identification, also known as environmental prediction, can provide data for the analysis of dynamic response and vibration reasons of the system. The load of large-scale structure is very complex, it is difficult to measure directly, but the load of the system can be deduced by the response signal of the structure and the known mathematical model of the system, and then the load spectrum can be obtained by statistics and synthesis according to the data under various working conditions. The properties and propagation path of the vibration source can be obtained by power spectrum analysis or correlation analysis.