Song Haiyan

Radiated noise sources location based on MVDR near-field focused beamforming

Noise sources image can be used to determine the spatial distribution of the major noise sources. Thereby we can adopt damping and noise-reducing measures pertinently. In the near-field, compared to the conventional beamforming (CBF), focused beamforming should compensates the time-delay difference and the magnitude attenuation by spherical wave rules according to the different curvature radiuses between the source and array elements, and the time-delay difference value is the 2-dimensional function of both bearing and range. In this paper, the MVDR near-field focused beamforming algorithm and wideband MVDR near-field focused beamforming algorithm are presented. The location performance of both single frequency line spectrum noise and wideband noise signal is improved markedly. Because of making use of various spectrum band signal energy fully, we can scale the noise sources spatial distribution more roundly.

Finite Element Analysis of Mechanical Characteristics of Dropped Eggs Based on Fluid-Solid Coupling Theory

It is important to study the properties and mechanics of egg drop impacts in order to reduce egg loss during processing and logistics and to provide a basis for the protective packaging of egg products. In this paper, we present the results of our study of the effects of the structural parameters on the mechanical properties of an egg using a finite element model of the egg. Based on Fluid-Solid coupling theory, a finite element model of an egg was constructed using ADINA, a finite element calculation and analysis software package. To simplify the model, the internal fluid of the egg was considered to be a homogeneous substance. The egg drop impact was simulated by the coupling solution, and the feasibility of the model was verified by comparison with the experimental results of a drop test. In summary, the modeling scheme was shown to be feasible and the simulation results provide a theoretical basis for the optimum design of egg packaging and egg processing equipment.