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Characteristics vibration and stiffness of astromesh deployable antenna is mainly decided by circle truss. So vibration of circle truss is necessary to be analyzed. At first, analyze the structure of the astromesh deployable antenna, and set up mass matrix, stiffness matrix and force vector of link ending points with the method of finite unit. Then transforming-coordinate matrixes and expanding-coordinate...
Errors model of 6-PTRT parallel robot is proposed by setting up the relation of pose errors and structural parameters based on the closed-vectors differential. Errors sensitivity index are defined by using of singular value of the matrix and are given to physical meanings. Errors synthetical sensitivity, direction sensitivity and maximum sensitivity are quantitatively analyzed through simulation,...
In this paper the simulation of spatial distribution of polarization spectrum components of a field scattered by hydrometeors is made. The emphasis is done on the necessity to watch the speed of the variation of field intensity distribution over the receiving antennas caused by the inertia of drops. This is the requirement to estimate the difference in transient process of hydrometeors with different...
A finite element (FE) model, which is based on transfer matrix analysis and local flexibility theorem, is introduced for crack identification of a static (non-rotating) rotor with an open crack. Through numerical simulation, the effects of the location and depth of the crack on the mode shapes and the changes in the eigenfrequencies of the cracked rotor are investigated, and the ratio of the changes...
Theoretical design and experiment are presented for a proposed plate type multi-degree-of-freedom piezoelectric motor. The method for calculating the working modal frequency of the piezoelectric motor is investigated, and the principles to determine the dimensions of the structure and spacing of the protrusions are provided. According to the design theory, a prototype was fabricated to test the practical...
Phononic crystals exhibit unique dynamic characteristics that make them act as tunable mechanical filters for elastic or acoustic wave propagation. The introducing of the idea of PCs in engineering structures provides a new technique for the control of vibration and noise. In this paper, basing on the Mindlin plate theory, the Timoshenko beam theory and the Bloch theorem, an efficient finite element...
In this paper, the performance of aerostatic thrust bearings compensated by different methods is investigated using computational fluid dynamics (CFD) method. By analyzing the relationships between the bearings' parameters and load carrying capacity (LCC), mass flow rate (MFR) and the maximum gas velocity (MGV), the effects of restrict area on the bearing's performance are discussed in the first time...
In order to improve the dynamics behavior of roll gimbal in an aerial three-axis ISP system while minimizing the mass and external size, the modal analysis with Finite Element Method (FEM) was carried out. Based on the modal analysis results, the structure of roll gimbal was optimized. Compared to the original structure, the dynamics performance of the optimized structure is improved remarkably, whose...
This paper deal with calculation of natural frequency stator core of asynchronous machine. Deformation of stator core is described in first part. Analytical and numerical calculation are presented in next part. Comparing of both methods is performed finally
In the free field, making full use of scalar and vector information of acoustic field can bring many advantages for acoustic measurement, but under the conditions of the existence of sound baffle, the sound field should be distorted due to the superposition of diffraction wave. Taking the soft spherical baffle as background, the sphere scattering model is established, the diffraction pressure field...
One approach using modal analysis and harmonic response to analyze the characteristics of machine tools is proposed in this paper. Dynamic theory and modeling method of MDOF system are introduced. Modal experiment is carried out to obtain modal frequency, damping and shape. Based on these parameters, a virtual dynamic model is established to match the actual one. Meanwhile, simulation and modal analysis...
This paper presents a nondestructive global damage identification method based on the changes in frequencies, mode shapes and flexibilities of vibration of structural system. The method is applied at an element level, the damage is represented by a reduction factor of the element bending stiffness and an adaptive genetic algorithms (AGA) is proposed to identify damage location and severity, which...
The vibration spectrum of the disk type PZT ceramics resonator with different diameter-to-thickness ratio was measured in the frequency range from 100 kHz to 1MHz. The resonant frequency ratio of fundamental mode to that of overtone mode was increased with the increasing of diameter-to-thickness ratio. With the same diameter, the resonant frequency ratio of fundamental mode to that of overtone mode...
With the fast growth of electronic products such as wireless telecommunication devices and personal computers, quartz crystal resonators are widely used as stable and precise frequency control components. Due to miniaturization of practical product and higher frequency requirements, how to avoid mode coupling which will severely affect product's quality becomes a key problem to be solved during the...
This paper includes a detailed study of Raman G peak analysis for metallic Single Wall Carbon Nanotubes. The higher frequency Lorentzian line shape and the lower frequency Breit-Wigner-Fano (BWF) line shape are two most intense features of Raman G peaks. BWF line shape originated from the Phonon-Plasmon coupling to an electronic continuum is an intrinsic property for metallic SWNTs. From different...
We have proposed a hollow tube type micropump which integrates a liquid flow driving part such as a PZT piezoelectric material and a tube part. And the flow function demonstrated by the hollow tube type micropump was evaluated and it is confirmed that the flow velocities by the pump were increased and decreased. We examined the improvement of the pump. Here, it is effective to give a large vibration...
A calculation model for simply supported box beam is established in the paper, and its natural frequency and vibration mode are analyzed through theoretical analysis and numerical simulation. The influence of elastic support to the beam frequency is also discussed, which showed that the elastic has great effect on beam frequency. Lastly, it can be concluded that the beam frequency can satisfied technical...
The actual bridge structures are not situated in the vacuum environment, so the dynamical behavior of the bridge structure will be affected with the geometrical deformations and the mass distributions due to the variation of the ambient medium, especially along the augment of bridge span. Taking into the effect of the static wind, temperature and deep water account synthetically, this paper analyzes...
A cylindrical traveling wave ultrasonic motor using outer excitation of two bending transducers is proposed in this paper. To avoid the drawbacks of conventional traveling wave ultrasonic motors, sandwich structure of PZT elements and d33 mode of PZT are used here. Working principle and design analysis by means of FEM method are detailed. A prototype motor has been fabricated and tested. Although...
Current ubiquitous computing research has focused on either ambient or tangible interfaces, neglecting the crossover between. In this demonstration, users will experience InfoStone, an interaction device that bridges the gap between ambient and tangible interaction. Users will also learn about design guidelines used in the creation of such interaction devices.
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