High-efficiency modal analysis and deformation prediction of rice transplanter based on effective independent method

2020 ◽  
Vol 168 ◽  
pp. 105126
Author(s):  
Ji Jiangtao ◽  
Chen Kaikang ◽  
Jin Xin ◽  
Wang Zhaoyang ◽  
Dai Baoqiong ◽  
...  
Keyword(s):  
Modal Analysis ◽  
High Efficiency ◽  
Independent Method ◽  
Deformation Prediction

The Modal Analysis of the Rotor of Electric Eddy Current Dynamometer Based on ADAMS

2012 ◽  
Vol 226-228 ◽  
pp. 290-294
Author(s):  
Xiang Bi An ◽  
Da Wei Li ◽  
Hu Wang ◽  
Long Wang
Keyword(s):  
Modal Analysis ◽  
Natural Frequency ◽  
Eddy Current ◽  
Critical Speed ◽  
High Efficiency ◽  
Great Influence ◽  
Motion Equation ◽  
Machine Design ◽  
Design And Optimization ◽  
Stiffness And Damping

The performance of the rotor of the electric eddy current dynamometer has a great influence on the capability of the dynamometer. The stiffness and damping of the rotor can be obtained by analyzing its motion equation. And the critical speed can be achieved by getting the natural frequency and the vibration through ADAMS based on the theory of flexibility. Based on the machine design handbook, some proofs were provided by the conclusion that the speed of the rotor should be the range of the different critical speed of the modal in order to assure the safety and high efficiency of the dynamometer. Focused on the need for the design of the rotor, this method which solves the difficulties of the intensive calculation in the design and optimization of the dynamometer’s rotor is exact and effective.

scholarly journals Using N-Norms for Analyzing Symmetric Protective Electrical Circuits with Triple Modal Reservation

Symmetry ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2390
Author(s):  
Yevgeniy S. Zhechev ◽  
Anna V. Zhecheva ◽  
Alexey A. Kvasnikov ◽  
Alexander M. Zabolotsky
Keyword(s):  
Modal Analysis ◽  
Electromagnetic Compatibility ◽  
High Efficiency ◽  
Electromagnetic Coupling ◽  
Total Duration ◽  
Ultra Wideband ◽  
Primary Circuit ◽  
Suggested Approach ◽  
Lower Amplitude ◽  
Trapezoidal Pulse

The redundancy of functional blocks and critical assemblies in radio-electronic equipment is among the most widely used techniques for increasing reliability. Complex redundant systems raise the problem of electromagnetic compatibility (EMC). Ignoring EMC requirements can lead to partial or complete REE failures. In this paper, the authors analyze a noise-protective electrical circuit with triple modal reservation (a promising type of cold redundancy). A multilayer stripline is investigated, the conductors of which are symmetrically arranged relative to two planes. On account of the strong electromagnetic coupling, this protective circuit can decompose dangerous ultra-wideband (UWB) interference received at the input of the primary or redundant circuits into unipolar pulses of lower amplitude. Using this approach, due to the symmetry of the conductors, equal decomposition efficiency could be achieved. However, the effect of UWB interference at the input of one of the conductors produces bipolar pulses at the output of the other conductors. In this paper, the authors evaluate the dangers of unipolar and bipolar decomposed pulses and use modal analysis to mathematically determine the polarities and amplitudes of the decomposed pulses at all output nodes for a pseudo-matched structure. By using the quasistatic approach with and without losses, the time responses to a trapezoidal pulse with a total duration of 60 ps, which simulates UWB interference, are obtained. To confirm the results of modal analysis and quasistatic simulation, an experimental study is performed. Using a stroboscopic oscilloscope DSA 8300, the authors obtained a transient response to a step excitation. Then, taking the derivative, the response to a trapezoidal pulse with a total duration of 140 ps was obtained. To analyze the criticality of the decomposed pulses, N-norms are used. In the general case, it is shown that the UWB interference is decomposed into four pulses of lower amplitude. At the same time, the value of each N-norm indicates its significant attenuation. For example, the amplitude of the UWB pulse acting on the input of the reserved conductor decreases by 10.31–8.93 times. Such results numerically demonstrate the high efficiency of the suggested approach when it comes to protecting equipment against UWB interference. It is also shown that the probability of dielectric breakdown and damage to electronic components in redundant circuits is lower than in a primary circuit. This is due to the fact that the value of N3 in the redundant circuit is 2.38 times less than in the primary circuit. However, the results demonstrate that arcing is highly probable both in primary and redundant circuits. Finally, aspects of symmetry/asymmetry in the problem under investigation are emphasized.

Acceleration of Modal Analysis by FMM Based on DRBEM

2012 ◽  
Author(s):  
Yixiong Wei ◽  
Qifu Wang ◽  
Yingjun Wang ◽  
Yunbao Huang ◽  
Linchi Zhang
Keyword(s):  
Boundary Element Method ◽  
Modal Analysis ◽  
Boundary Element ◽  
High Efficiency ◽  
Fast Multipole Method ◽  
Matrix Multiplication ◽  
Time Dimension ◽  
Hessenberg Matrix ◽  
Low Efficiency ◽  
Element Method

This paper proposes a novel algorithm to accelerate the process of modal analysis in 3D elastodynamic problems in BEM (boundary element method) with high accuracy. Because of low efficiency and high cost, conventional BEM is rarely used for solving 3D elastodynamics problems in engineering problems. With applying the DRBEM (dual reciprocity boundary element method) to form new integral equations of 3D elastodynamics problems to reduce time complexity by using reciprocity method twice, we introduce modified FMM (fast multipole method) to simplify the computation process and improve the efficiency from O(n2) to O(n) in matrix multiplication. The main features in this method are: (1) Position Location (PL) algorithm is used to eliminate one layer of nested loops in conventional FMM, and which achieve a good performance in efficiency; (2) time dimension integrations in the element of matrices are canceled for high efficiency; (3) instead of the interaction between points, we apply point to element interaction method for saving plenty of the CPU cost in modified FMM; (4) it does not need to compute complex dynamic fundamental solutions which are necessary in conventional BEM. In this algorithm, the corresponding eigenvalue problem is solved by Hessenberg matrix and QR reduction algorithm iteratively. We have tested our method in numerical examples during last section, and have observed significant optimal results in efficiency and accuracy.

Modal analysis of high-efficiency wideband reflective gratings

2012 ◽  
Vol 14 (5) ◽  
pp. 055705 ◽  
Author(s):  
Anduo Hu ◽  
Changhe Zhou ◽  
Hongchao Cao ◽  
Jun Wu ◽  
Junjie Yu ◽  
...  
Keyword(s):  
Modal Analysis ◽  
High Efficiency

Dynamic Optimization Design of a Warship’s Gearbox Based on FEM

2011 ◽  
Vol 86 ◽  
pp. 662-665
Author(s):  
Yan Hua Xue ◽  
Xiao Hong Li ◽  
Zhi Guang Wang ◽  
Jie Song
Keyword(s):  
Modal Analysis ◽  
Dynamic Optimization ◽  
High Speed ◽  
Optimization Design ◽  
High Efficiency ◽  
Light Weight ◽  
Heavy Load ◽  
Double Frequency ◽  
Gearbox Vibration ◽  
Vibration Modal

The transmission system of warship’s gearbox is increasingly developing in the direction of high-speed, high-efficiency, heavy-load and light-weight, and the requirements of vibration are increasing as well. The gearbox designed according to static standard often has various problems of instability and vibration which greatly weaken the behaviors of gearbox and influence the invisibility performance of warship seriously. To improve the vibration characteristics of gearbox, vibration modal analysis of a warship’s gearbox is studied based on FEM. In order to avoid resonance in transmission, double-frequency dynamic optimization design of a gearbox is studied and discussed. The method and conclusions can be used as a reference of design of warship’s gearbox.

Dynamic Analysis Based on ANSYS of Turning and Grinding Compound Machine Spindle Box

2012 ◽  
Vol 433-440 ◽  
pp. 524-529
Author(s):  
Zhan Hui Shu ◽  
Qiu Shi Han
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Machine Tools ◽  
High Speed ◽  
High Efficiency ◽  
Three Dimensional ◽  
Element Model ◽  
Response Analysis ◽  
Element Analysis ◽  
Analysis And Design

With constant development of machine tools toward the direction of high speed, high precision, high efficiency and high compound rapidly. The performance of high-speed machine tools is affected by the dynamic characteristic of machine tools in the very great degree. More and more attention is played to them and higher and higher demands are proposed. Finite element method is a kind of fast and efficient auxiliary tools in modern engineering analysis and design. Three-dimensional finite element model of spindle box is established in this paper based on large finite element analysis software ANSYS. Through modal analysis, the first five order natural frequency, vibration mode and various order vibrating modal characteristics are obtained. These results are verified by using the method of experimental modal. Harmonic response analysis is carried after doing modal analysis on spindle box. Response and stress under different frequency are obtained. Continuous dynamic characteristics are forecasted.

Microcalorimeters for X-Ray Spectroscopy

1988 ◽  
Vol 102 ◽  
pp. 41
Author(s):  
E. Silver ◽  
C. Hailey ◽  
S. Labov ◽  
N. Madden ◽  
D. Landis ◽  
...  
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Thermal Response ◽  
Low Noise ◽  
High Resolution Spectroscopy ◽  
Superconducting Transition ◽  
Sapphire Substrates ◽  
Laboratory Plasmas ◽  
Adiabatic Demagnetization ◽  
Theoretical Predictions

The merits of microcalorimetry below 1°K for high resolution spectroscopy has become widely recognized on theoretical grounds. By combining the high efficiency, broadband spectral sensitivity of traditional photoelectric detectors with the high resolution capabilities characteristic of dispersive spectrometers, the microcalorimeter could potentially revolutionize spectroscopic measurements of astrophysical and laboratory plasmas. In actuality, however, the performance of prototype instruments has fallen short of theoretical predictions and practical detectors are still unavailable for use as laboratory and space-based instruments. These issues are currently being addressed by the new collaborative initiative between LLNL, LBL, U.C.I., U.C.B., and U.C.D.. Microcalorimeters of various types are being developed and tested at temperatures of 1.4, 0.3, and 0.1°K. These include monolithic devices made from NTD Germanium and composite configurations using sapphire substrates with temperature sensors fabricated from NTD Germanium, evaporative films of Germanium-Gold alloy, or material with superconducting transition edges. A new approache to low noise pulse counting electronics has been developed that allows the ultimate speed of the device to be determined solely by the detector thermal response and geometry. Our laboratory studies of the thermal and resistive properties of these and other candidate materials should enable us to characterize the pulse shape and subsequently predict the ultimate performance. We are building a compact adiabatic demagnetization refrigerator for conveniently reaching 0.1°K in the laboratory and for use in future satellite-borne missions. A description of this instrument together with results from our most recent experiments will be presented.

Imaging and diffraction modes in Scanning Transmission Electron Microscopy

1986 ◽  
Vol 44 ◽  
pp. 684-687
Author(s):  
J. M. Cowley ◽  
R. Glaisher ◽  
J. A. Lin ◽  
H.-J. Ou
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
High Efficiency ◽  
Fiber Optic ◽  
Image Intensifier ◽  
Detector System ◽  
Detector Plane ◽  
Secondary Electrons ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Special Detector

Some of the most important applications of STEM depend on the variety of imaging and diffraction made possible by the versatility of the detector system and the serial nature, of the image acquisition. A special detector system, previously described, has been added to our STEM instrument to allow us to take full advantage of this versatility. In this, the diffraction pattern in the detector plane may be formed on either of two phosphor screens, one with P47 (very fast) phosphor and the other with P20 (high efficiency) phosphor. The light from the phosphor is conveyed through a fiber-optic rod to an image intensifier and TV system and may be photographed, recorded on videotape, or stored digitally on a frame store. The P47 screen has a hole through it to allow electrons to enter a Gatan EELS spectrometer. Recently a modified SEM detector has been added so that high resolution (10Å) imaging with secondary electrons may be used in conjunction with other modes.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

The use of high-resolution FESEM to study solid-state phase transformations and reactions

1994 ◽  
Vol 52 ◽  
pp. 1028-1029
Author(s):  
P. G. Kotula ◽  
D. D. Erickson ◽  
C. B. Carter
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Phase Transformations ◽  
High Efficiency ◽  
Sol Gel ◽  
Quantitative Information ◽  
Solid State Reactions ◽  
Critical Dimensions ◽  
Backscattered Electrons ◽  
Backscattered Electron

High-resolution field-emission-gun scanning electron microscopy (FESEM) has recently emerged as an extremely powerful method for characterizing the micro- or nanostructure of materials. The development of high efficiency backscattered-electron detectors has increased the resolution attainable with backscattered-electrons to almost that attainable with secondary-electrons. This increased resolution allows backscattered-electron imaging to be utilized to study materials once possible only by TEM. In addition to providing quantitative information, such as critical dimensions, SEM is more statistically representative. That is, the amount of material that can be sampled with SEM for a given measurement is many orders of magnitude greater than that with TEM.In the present work, a Hitachi S-900 FESEM (operating at 5kV) equipped with a high-resolution backscattered electron detector, has been used to study the α-Fe2O3 enhanced or seeded solid-state phase transformations of sol-gel alumina and solid-state reactions in the NiO/α-Al2O3 system. In both cases, a thin-film cross-section approach has been developed to facilitate the investigation. Specifically, the FESEM allows transformed- or reaction-layer thicknesses along interfaces that are millimeters in length to be measured with a resolution of better than 10nm.

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