Applications of Jacobi’s Elliptic Functions in Forced Vibration in Nonlinear Rotor Dynamics

In this paper studied a rotary system with a nonlinearity, the equations of motion of which is one of the types of the Duffing’s equations with multidegree-of-freedom, and also consider the advantages of using the elliptic function method to solve problems of this type. The system studied in this paper is also distinguished by the fact that in addition to the rotor vibrations in elastic supports with a nonlinearity, the vibrations of the foundation are also taken into account. The article presents a comparative analysis of the numerical Runge-Kutta-Fehlberg's 4-order method with an error estimate of 5-order, the approximate analytical Van der Pol’s method and the elliptic function method proposed by the authors by comparing the obtained equations of motion of the system, as well as by comparing the constructed frequency response characteristic. From the results obtained, it follows that the method proposed by the authors can serve as a more accurate, general case of previously used approximate methods.

Frequency Response Characteristic (FRC) Curve and Fast Frequency Response Assessment in High Renewable Power Systems

This letter introduces a frequency response characteristic (FRC) curve and its application in high renewable power systems. In addition, the letter presents a method for fast frequency response assessment and frequency nadir prediction without performing dynamic simulations using detailed models. The proposed FRC curve and fast frequency response assessment method are useful for operators to understand frequency response performance of high renewable systems in real time.

Design and Analysis of Compound Multilayer Metamaterial Filter in THz Region

A periodic microstructure with dielectric and metal layers is proposed to obtain a bandpass filter. The multilayer microstructure is compounded of ring cross slot and cross slot. The center frequency of the filter is 0.338THz with a 3dB bandwidth of 75.62GHz. The maximum insertion loss in the pass band reaches 0.60dB. The bandedge transitions of the rejection bands are 232dB/THz and 176dB/THz, respectively. Furthermore, the physical mechanism of near field distribution and the influence of two factors (the number of metal layer and dielectric layer) on the passband have been studied. Meanwhile, the frequency response is analyzed for different incident angles and polarizations. The frequency response characteristic is insensitive to the polarization, and a good performance for incident angle of the transmission is obtained. It can be applied to THz atmospheric communication system.