Tcw Chen¹, Wray Marriott², Ann Nicholson³, Tim Chen⁴, Mars Kmieckowiak⁵, Jcy Chen^6,*

Sound & Vibration, Vol.53, No.2, pp. 29-37, 2019, DOI:10.32604/sv.2019.04224

Abstract In this paper, a method sustaining system stability after decomposition is proposed. Based on the stability criterion derived from the energy function, a set of intelligent controllers is synthesized which is used to maintain the stability of the system. The sustainable stability problem can be reformulated as a Linear Matrix Inequalities (LMI) problem. The key to guaranteeing the stability of the system as a whole is to find a common symmetrically positive definite matrix for all subsystems. Furthermore, the Evolved Bat Algorithm (EBA) is employed to replace the pole assignment method and the conventional mathematical methods for solving the LMI.… More >

Deshui Xu, Jingtao Du^*, Yuhao Zhao

Sound & Vibration, Vol.53, No.2, pp. 16-28, 2019, DOI:10.32604/sv.2019.04033

Abstract In this paper, an accurate series solution for the longitudinal vibration analysis of elastically coupled nanorods system is established, in which artificial springs are introduced to simulate such general coupling and boundary conditions. Energy formulation is derived for the description of axial dynamics of multiple coupled nanorods based on Eringen nonlocal elasticity. For each nanorod component, its longitudinal vibration displacement function is invariantly assumed as the superposition of Fourier series and boundary smoothed supplementary polynomials, with the aim to make all the spatial differential sufficiently continuous across each rod. All the unknown coefficients are determined in conjunction with Rayleigh-Ritz procedure… More >

Jianing Zhang^1,2, Ziying Yu¹, Hengxu Yang^1,2, Ming Wu¹, Jun Yang^1,2,*

Sound & Vibration, Vol.53, No.2, pp. 2-15, 2019, DOI:10.32604/sv.2019.03783

Abstract Ultrasound can be used as a carrier to realize wireless communication to and from a metal-enclosed space, which has the characteristics such as immunity to the electromagnetic shielding effect and non-destructive penetration of metal obstacles. This paper firstly reviews the previous studies in the field of ultrasonic wireless communication through metal barriers, and summarizes their achievements and the existing problems. Secondly, an overview of the research methods involved in studying the characteristic of acoustic-electric channel is presented, and the principles are introduced for the actual measurement method, equivalent circuit method, ABCD parameter method, finite element analysis method and time-domain finite… More >

Wen Zhao, Dongxing Mao^*, Zaixiu Jiang

Sound & Vibration, Vol.53, No.1, pp. 37-46, 2019, DOI:10.32604/sv.2019.04368

Abstract In order to analyze the effect of the background flow on the sound prediction of fine-scale turbulence noise, the sound spectra from static and flow environments are compared. It turns out that, the two methods can obtain similar predictions not only at 90 deg to the jet axis but also at mid- and high frequencies in other directions. The discrepancies of predictions from the two environments show that the effect of the jet flow on the sound propagation is related to low frequencies in the downstream and upstream directions. It is noted that there is an obvious advantage of computational… More >

Jianliang Jiang¹, Bosun Xie^1,2,*, Haiming Mai¹

Sound & Vibration, Vol.53, No.1, pp. 25-36, 2019, DOI:10.32604/sv.2019.04259

Abstract Ambisonics is a series of spatial sound reproduction system based on spatial harmonics decomposition and each order approximation of sound field. Ambisonics signals are originally intended for loudspeakers reproduction. By using head-related transfer functions (HRTFs) filters, binaural Ambisonics converts the Ambisonics signals for static or dynamic headphone reproduction. In present work, the performances of static and dynamic binaural Ambisonics reproduction are evaluated and compared. The mean binaural pressure errors across target source directions are first analyzed. Then a virtual source localization experiment is conducted, and the localization performances are evaluated by analyzing the percentages of front-back and up-down confusion, the… More >

Yinhu Qiao^1,*, Chunyan Zhang¹, Jiang Han²

Sound & Vibration, Vol.53, No.1, pp. 14-24, 2019, DOI:10.32604/sv.2019.04120

Abstract This paper presents a theoretical analysis of vibration control technology of wind turbine blades made of piezoelectric intelligent structures. The design of the blade structure, which is made from piezoelectric material, is approximately equivalent to a flat shell structure. The differential equations of piezoelectric shallow shells for vibration control are derived based on piezoelectric laminated shell theory. On this basis, wind turbine blades are simplified as elastic piezoelectric laminated shells. We establish the electromechanical coupling system dynamic model of intelligent structures and the dynamic equation of composite piezoelectric flat shell structures by analyzing simulations of active vibration control. Simulation results… More >

Xueyun Ruan^1,2, Wei Huang¹, Linke Zhang³, Yan Gao^2,*

Sound & Vibration, Vol.53, No.1, pp. 2-13, 2019, DOI:10.32604/sv.2019.04562

Abstract Outdoor power transformers are one of the most pervasive noise sources in power transmission and distribution systems. Accurate prediction of outdoor noise propagation plays a dominant role for the evaluation and control of noise relevant to the transformer stations. In this paper surface vibration tests are carried out on a scale model of a single-phase transformer tank wall at different excitation frequencies. The phase and amplitude of test data are found to be randomly distributed when the excitation frequency exceeds the seventh mode frequency, which allows the single-phase power transformer to be simplified as incoherent point sources. An outdoor-coherent model… More >