Dynamic Performance and Structural Optimization of Large-Scale Machine Table

2014 ◽  
Vol 615 ◽  
pp. 313-316
Author(s):  
Zai Liang Chen ◽  
Luo Hong Deng ◽  
Cong Jing
Keyword(s):  
Structural Optimization ◽  
Natural Frequency ◽  
Dynamic Optimization ◽  
Large Scale ◽  
Lattice Structure ◽  
Dynamic Performance ◽  
Structure Parameters ◽  
Milling Machine ◽  
Plate Dynamic ◽  
The Ideal

Designed new table for large floor boring and milling machine, used ANSYS to optimize the structure of the table as a whole. According to the contours of removable material the materials which can be removed, obtained the inner ribs layout of table and the sand holes location of rib plate. Dynamic optimization variables on basic ribs cell, studied the effect of steel lattice structure parameters influenced on the natural frequency of the lattices and the related parameter of lattices influenced on whole table, to get the ideal rib lattice structure after optimizing again. Optimized bench can reduce quality, increase rigidity and dynamic performance.

Frequency Domain Structural Optimization of a Flexible Manipulator Incorporating a PD Controller in the Design Stage

1999 ◽  
Author(s):  
Yong Hoon Chang ◽  
Ali Seireg
Keyword(s):  
Structural Optimization ◽  
Natural Frequency ◽  
Dynamic Performance ◽  
Integrated Design ◽  
Flexible Manipulator ◽  
Design Stage ◽  
Pd Controller ◽  
Design Strategies ◽  
Flexible Mode ◽  
Modal Mass

Abstract This study investigates the potential advantages of integrated design strategies for flexible manipulators that utilize a controller in the process of optimizing the structural design. Clamped free and clamped mass beam models are considered in the investigation for the structural optimization with respect to natural frequencies and mass. A PD controller is utilized in the design process with several objective functions that incorporate weighted combinations of the mass of the structure, modal mass, modal stiffness, and the natural frequency of the rigid mode and the dominant natural frequency of the flexible mode. The results show that the objective function, which minimizes the mass and the product of the modal mass and modal stiffness of the rigid mode and maximize the natural frequency of the flexible mode with appropriate weighting factors, gave the best dynamic performance. Although a two link tubular planar manipulator with a PD controller and assumed beam models for the links is considered in the optimization based on modal parameters, the reported approach can be extended to time domain optimization of multi-link spacial robots with complex structures designed to perform particular tasks.

Structure Sensitivity Analysis and Dynamic Performance Optimization of Marine Gearbox

2017 ◽  
Author(s):  
Tengjiao Lin ◽  
Daokun Xie ◽  
Ziran Tan ◽  
Bo Liu
Keyword(s):  
Sensitivity Analysis ◽  
Performance Optimization ◽  
Optimization Design ◽  
Dynamic Performance ◽  
Structure Sensitivity ◽  
Superposition Method ◽  
Structure Parameters ◽  
Analysis Model ◽  
Vibration Acceleration ◽  
Response Optimization

The aim of this paper is to investigate the influence of structure parameters on the vibration characteristics and improve the dynamic performance of marine gearbox. A finite element model was established to solve the dynamic response by using modal superposition method. Based on the theory of multi-objective optimization design, the structure sensitivity analysis model of marine gearbox was established, which takes the structure parameters of the housing as design variables. The modal and response sensitivity was obtained by using the optimal gradient method. According to the results of sensitivity analysis, a modal and response optimization model of marine gearbox was established. The objective was to avoid natural frequencies from the excitation frequencies and minimize the root mean square of vibration acceleration of the evaluating points on the surface of housing. Then the modal optimization and response optimization of gearbox were carried out by using zero-order and first-order optimization method. The results indicate that the dynamic optimization of the gearbox can be achieved. After optimization, the amplitude of vibration acceleration of the evaluating points on the housing surface has been reduced and the resonance of marine gearbox can be avoided.

scholarly journals A Novel Methodology for Adaptive Coordination of Multiple Controllers in Electrical Grids

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1474
Author(s):  
Ruben Tapia-Olvera ◽  
Francisco Beltran-Carbajal ◽  
Antonio Valderrabano-Gonzalez ◽  
Omar Aguilar-Mejia
Keyword(s):  
Power Systems ◽  
Power System ◽  
Electric Power ◽  
Large Scale ◽  
Short Circuit ◽  
Dynamic Performance ◽  
Low Frequency ◽  
Electric Power System ◽  
Design Stage ◽  
Positive Interaction

This proposal is aimed to overcome the problem that arises when diverse regulation devices and controlling strategies are involved in electric power systems regulation design. When new devices are included in electric power system after the topology and regulation goals were defined, a new design stage is generally needed to obtain the desired outputs. Moreover, if the initial design is based on a linearized model around an equilibrium point, the new conditions might degrade the whole performance of the system. Our proposal demonstrates that the power system performance can be guaranteed with one design stage when an adequate adaptive scheme is updating some critic controllers’ gains. For large-scale power systems, this feature is illustrated with the use of time domain simulations, showing the dynamic behavior of the significant variables. The transient response is enhanced in terms of maximum overshoot and settling time. This is demonstrated using the deviation between the behavior of some important variables with StatCom, but without or with PSS. A B-Spline neural networks algorithm is used to define the best controllers’ gains to efficiently attenuate low frequency oscillations when a short circuit event is presented. This strategy avoids the parameters and power system model dependency; only a dataset of typical variable measurements is required to achieve the expected behavior. The inclusion of PSS and StatCom with positive interaction, enhances the dynamic performance of the system while illustrating the ability of the strategy in adding different controllers in only one design stage.

THE FOREST FOR THE TREES: SOCIETY AND THE HOUSEHOLD IN EARLY MODERN EUROPE

1998 ◽  
Vol 41 (4) ◽  
pp. 1161-1172 ◽  
Author(s):  
JOEL F. HARRINGTON
Keyword(s):  
Large Scale ◽  
University Of Pennsylvania ◽  
Italian Renaissance ◽  
German History ◽  
Early Modern Europe ◽  
Cambridge University ◽  
Johns Hopkins University ◽  
Big Picture ◽  
To Come ◽  
The Ideal

Gender relations in German history: power, agency, and experience from the sixteenth to the twentieth century. Edited by Lynn Abrams and Elizabeth Harvey. London: UCL, 1996. Pp. x+262. ISBN 1-85728-485-2. £12.95.Adultery and divorce in Calvin's Geneva. By Robert M. Kingdon. Cambridge, Mass., and London: Harvard UP, 1995. Pp. ix+214. ISBN 0-674-00520-1 (hb). £18.50.Housecraft and statecraft: domestic service in Renaissance Venice, 1400–1600. By Dennis Romano. Baltimore: Johns Hopkins University Press, 1996. Pp. xxvi+333. ISBN 0-8018-5288-9. £37.00.The European nobility, 1400–1800. By Jonathan Dewald. New approaches to European history, ix. Cambridge: Cambridge University Press, 1996. Pp. xvii+209. ISBN 0-521-42528-x (pb). £12.95.Garden and grove: the Italian Renaissance garden in the English imagination, 1600–1750. By John Dixon Hunt. Philadelphia: University of Pennsylvania, 1996. Pp. xix+268. ISBN 0-8122-1604-0 (pb). £23.50.Like an ancient woodsman or a guide through the Amazonian jungle, the ideal historian possesses at least two kinds of expertise: enough familiarity with the general terrain to plan successful expeditions and enough experience in the field to make inevitable adjustments to ‘the big picture’ when underway. Of course in the real world (of both geography and history) the tasks of exploration and cartography are often bifurcated, without necessarily disastrous results. The historian who is equally skilled at both close-up description and large-scale theorizing is consequently celebrated as a rare and valued anomaly. Meanwhile, for most of us stumbling scouts, the world beyond our familiar trails remains largely one of learned lore, with connections to our own limited forays often vague at best. Unless, of course, we are fortunate enough to come across something which provides an almost magical link between the narrow and the wide, the micro and the macro.

Towards 3D image-based nanocrystallography by means of transmission electron goniometry

2004 ◽  
Vol 839 ◽  
Author(s):  
Peter Moeck ◽  
Wentao Qin ◽  
Philip B. Fraundorf
Keyword(s):  
Lattice Structure ◽  
Three Dimensions ◽  
Structural Defects ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Z Contrast ◽  
Individual Nanoparticles ◽  
Nanocrystal Model ◽  
The Ideal

ABSTRACTIt is well known that the crystallographic phase and morphology of many materials changes with the crystal size in the tens of nanometer range and that many nanocrystals possess structural defects in excess of their equilibrium levels. A need to determine the ideal and real structure of individual nanoparticles, therefore, arises. High-resolution phase-contrast transmission electron microscopy (TEM) and atomic resolution Z-contrast scanning TEM (STEM) when combined with transmission electron goniometry offer the opportunity of develop dedicated methods for the crystallographic characterization of nanoparticles in three dimensions. This paper describes tilt strategies for taking data from individual nanocrystals “as found”, so as to provide information on their lattice structure and orientation, as well as on the structure and orientation of their surfaces and structural defects. Internet based java applets that facilitate the application of this technique for cubic crystals with calibrated tilt-rotation and double-tilt holders are mentioned briefly. The enhanced viability of image-based nanocrystallography in future aberration-corrected TEMs and STEMs is illustrated on a nanocrystal model system.

Study on a Novel MEMS High G Acceleration Sensor

2012 ◽  
Vol 490-495 ◽  
pp. 499-503
Author(s):  
Ping Li ◽  
Yun Bo Shi ◽  
Jun Liu ◽  
Shi Qiao Gao
Keyword(s):  
Resonant Frequency ◽  
Natural Frequency ◽  
Impact Load ◽  
Hopkinson Bar ◽  
Experimental Results ◽  
Structure Parameters ◽  
Acceleration Sensor ◽  
Piezoresistive Effect ◽  
Sensor Structure ◽  
The Impact

This paper presents a novel MEMS high g acceleration sensor based on piezoresistive effect. For the designed sensor structure, the formula of stress, natural frequency and damping was derived in theory, and the resonant frequency can up to 500kHz. After the structure parameters were designed, the sensor was fabricated by the standard processing technology, and the sensitivity was tested by Hopkinson bar. According to the experimental results, the sensitivity of the high g acceleration sensor is 0.125μV/g at the impact load of 164,002g.

scholarly journals Applying Biomimetic Principles to Thermoelectric Cooling Devices for Water Collection

2017 ◽  
Vol 7 (3) ◽  
pp. 27
Author(s):  
Kyle B Davidson ◽  
Bahram Asiabanpour ◽  
Zaid Almusaied
Keyword(s):  
Large Scale ◽  
Cost Effective ◽  
Thermoelectric Cooling ◽  
Device Structure ◽  
Cooling Systems ◽  
Cooling Devices ◽  
Water Collection ◽  
Maximum Water ◽  
The Ideal

The shortage of freshwater resources in the world has developed the need for sustainable, cost-effective technologies that can produce freshwater on a large scale. Current solutions often have extensive manufacturing requirements, or involve the use of large quantities of energy or toxic chemicals. Atmospheric water generating solutions that minimize the depletion of natural resources can be achieved by incorporating biomimetics, a classification of design inspired by nature. This research seeks to optimize thermoelectric cooling systems for use in water harvesting applications by analyzing the different factors that affect surface temperature and water condensation in TEC devices. Further experiments will be directed towards developing a robust, repeatable system, as well as an accurate measurement system. Surface modifications, device structure and orientation, and power generation will also be studied to better understand the ideal conditions for maximum water collection in thermoelectric cooling systems.

Large scale structural optimization of trimetallic Cu–Au–Pt clusters up to 147 atoms

2017 ◽  
Vol 686 ◽  
pp. 103-110 ◽  
Author(s):  
Genhua Wu ◽  
Yan Sun ◽  
Xia Wu ◽  
Run Chen ◽  
Yan Wang
Keyword(s):  
Structural Optimization ◽  
Large Scale
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