Design Optimization of Enclosed Liquid Containers With Baffles for Sloshing and Impact

2004 ◽  
Author(s):  
T. C. Kingsley ◽  
K. J. Craig
Keyword(s):  
Frequency Domain ◽  
Impact Analysis ◽  
Cfd Simulation ◽  
Low Frequency ◽  
Frequency Measurement ◽  
Optimization Method ◽  
Multidisciplinary Optimization ◽  
Qualitative Comparison ◽  
Measurement Capability ◽  
Design And Optimization

A multidisciplinary optimization method is presented to support the design process of partially-filled liquid containers subject to the disciplines of sloshing and impact analysis. This paper represents a part of a study on Multidisciplinary Design and Optimization of liquid containers, and shows experimental techniques used to try to better understand sloshing as a phenomenon and to evaluate the capabilities of the commercial Computational Fluid Dynamics (CFD) code in question. Experimental validation includes qualitative comparison of visual free-surface behavior and quantitative comparisons of pressure measurements in the time and frequency domain. The liquid motion exhibits good comparisons in time with some deviations in wave amplitude due to a modification of the low frequency content of the input signal to the CFD simulation. This modification was caused by both the experimental signal filtration process and deficiencies in the low-frequency measurement capability of the accelerometer. In the frequency domain the first two odd oscillatory modes are accurately captured. A candidate objective function for the quantitative evaluation of the sloshing phenomenon is proposed. Using the response surface method in LS-OPT, various single (sloshing or impact only) and multidisciplinary optimization formulations are presented and results are examined. As expected, the multidisciplinary optimum proved to be a compromise between the optima obtained when considering the two single disciplines independently.

scholarly journals A phase-locked loop using ESO-based loop filter for grid-connected converter: performance analysis

2021 ◽  
Author(s):  
Baoling Guo ◽  
Seddik Bacha ◽  
Mazen Alamir ◽  
Julien Pouget
Keyword(s):  
Performance Analysis ◽  
Frequency Domain ◽  
Low Frequency ◽  
Experimental Tests ◽  
Frequency Measurement ◽  
Phase Locked Loop ◽  
Frequency Domain Analysis ◽  
Loop Filter ◽  
Control Stability ◽  
Unbalanced Grid

AbstractAn extended state observer (ESO)-based loop filter is designed for the phase-locked loop (PLL) involved in a disturbed grid-connected converter (GcC). This ESO-based design enhances the performances and robustness of the PLL, and, therefore, improves control performances of the disturbed GcCs. Besides, the ESO-based LF can be applied to PLLs with extra filters for abnormal grid conditions. The unbalanced grid is particularly taken into account for the performance analysis. A tuning approach based on the well-designed PI controller is discussed, which results in a fair comparison with conventional PI-type PLLs. The frequency domain properties are quantitatively analysed with respect to the control stability and the noises rejection. The frequency domain analysis and simulation results suggest that the performances of the generated ESO-based controllers are comparable to those of the PI control at low frequency, while have better ability to attenuate high-frequency measurement noises. The phase margin decreases slightly, but remains acceptable. Finally, experimental tests are conducted with a hybrid power hardware-in-the-loop benchmark, in which balanced/unbalanced cases are both explored. The obtained results prove the effectiveness of ESO-based PLLs when applied to the disturbed GcC.

Optimization design of bonnet inner based on pedestrian head protection and stiffness requirements

2017 ◽  
Vol 06 (01) ◽  
pp. 1750005 ◽  
Author(s):  
Xiongqi Peng ◽  
Purit Thanakijkasem ◽  
Xiaomin Zeng ◽  
Hongsheng Lu
Keyword(s):  
Optimization Design ◽  
Parametric Design ◽  
Optimization Method ◽  
Multidisciplinary Optimization ◽  
Fe Model ◽  
Optimization Analysis ◽  
Stiffness Analysis ◽  
Design And Optimization ◽  
Car Accidents ◽  
Head Protection

Head impact with bonnet is one of the major causes for pedestrian severe injury or fatality in car accidents. This paper proposes a multidisciplinary design optimization method for bonnet inner based on pedestrian head protection along with bonnet stiffness requirement. A finite element (FE) model of a child headform impactor is developed and verified via simulation according to Global Technical Regulation No. 9 (GTR No. 9). Static stiffness analysis and headform collision simulation against one impact point for a particular bonnet are implemented. Parametric design and optimization analysis are carried out. Optimization solution significantly achieves a better head protection effect, which clearly affirms the feasibility of the proposed multidisciplinary optimization method and provides a reference approach to optimal design of engine bonnet inner.

Three-Dimensional Complex Groove Reconstruction of Cutting Tools Using Multidisciplinary Design Optimization Method

2009 ◽  
Vol 628-629 ◽  
pp. 323-328
Author(s):  
Guang Yu Tan ◽  
Guang Jun Liu ◽  
Guan Hui Li
Keyword(s):  
Temperature Field ◽  
Stress Field ◽  
Multidisciplinary Design Optimization ◽  
Cutting Tools ◽  
Three Dimensional ◽  
Optimization Method ◽  
Multidisciplinary Optimization ◽  
Working Environment ◽  
Coupling Effects ◽  
Design And Optimization

In the design and optimization of cutting tool’s groove, it is necessary to comprehensively consider the multidisciplinary coupling effects of stress field, temperature field and working environment, and balance the coupling effects on the cutting performance. The multidisciplinary optimization method is employed to study the 3D complex groove reconstruction of cutting tools in this paper. The two-level reconstruction approach is proposed. The groove reconstruction of waved-edge insert is presented as a numerical example, and an optimal design of the groove is obtained. The optimization results show that the reconstructed tool has a satisfied performance on the stress field and temperature field.

scholarly journals Multi-scale time-frequency domain full waveform inversion with a weighted local correlation-phase misfit function

2019 ◽  
Vol 16 (6) ◽  
pp. 1017-1031 ◽  
Author(s):  
Yong Hu ◽  
Liguo Han ◽  
Rushan Wu ◽  
Yongzhong Xu
Keyword(s):  
Frequency Domain ◽  
Seismic Data ◽  
Waveform Inversion ◽  
Low Frequency ◽  
Full Waveform Inversion ◽  
Local Correlation ◽  
Time Frequency ◽  
Model Dependence ◽  
Full Waveform ◽  
Frequency Components

Abstract Full Waveform Inversion (FWI) is based on the least squares algorithm to minimize the difference between the synthetic and observed data, which is a promising technique for high-resolution velocity inversion. However, the FWI method is characterized by strong model dependence, because the ultra-low-frequency components in the field seismic data are usually not available. In this work, to reduce the model dependence of the FWI method, we introduce a Weighted Local Correlation-phase based FWI method (WLCFWI), which emphasizes the correlation phase between the synthetic and observed data in the time-frequency domain. The local correlation-phase misfit function combines the advantages of phase and normalized correlation function, and has an enormous potential for reducing the model dependence and improving FWI results. Besides, in the correlation-phase misfit function, the amplitude information is treated as a weighting factor, which emphasizes the phase similarity between synthetic and observed data. Numerical examples and the analysis of the misfit function show that the WLCFWI method has a strong ability to reduce model dependence, even if the seismic data are devoid of low-frequency components and contain strong Gaussian noise.

Mineral interfacial processes in the method of induced polarization

Geophysics ◽  
1984 ◽  
Vol 49 (7) ◽  
pp. 1105-1114 ◽  
Author(s):  
James D. Klein ◽  
Tom Biegler ◽  
M.D. Horne
Keyword(s):  
Frequency Domain ◽  
Diffusion Layer ◽  
Electrode Potential ◽  
Rotation Speed ◽  
Low Frequency ◽  
Rotating Disk ◽  
Active Species ◽  
Hydrodynamic Theory ◽  
Electrode Polarization ◽  
Disk Electrodes

A phenomenological laboratory investigation has been conducted of the IP response of pyrite, chalcopyrite, and chalcocite. The technique that was used is standard in electrochemistry and employs rotating disk electrodes. The effect of rotation is to stir the electrolyte and thus to restrict the maximum distance available for diffusion of electroactive aqueous species. For high rotation speed and low excitation frequencies, the mean diffusion length exceeds the thickness of the diffusion layer. The net effect is to reduce the electrode impedance at low frequency. The thickness of the diffusion layer and thus the impedance at low frequency can be controlled by the rotation speed. Measurements using rotating disk electrodes have been conducted in both the time domain and the frequency domain. For both pyrite and chalcopyrite, the results were the same: no dependence on rotation was observed. For frequency domain measurements with chalcocite, a strong dependence on rotation was observed. The interpreted diffusion layer thickness was found to depend on rotation speed to the [Formula: see text] power, in agreement with results predicted by hydrodynamic theory. The results of this study imply that there are two physical processes responsible for electrode polarization in the IP method. For chalcocite and perhaps other related copper sulfide minerals, the probable mechanism is diffusion of copper ions in the groundwater. In case, the phenomenon is correctly described by the Warburg impedance. Chalcocite’s distinctive response is thought to be related to its forming a reversible oxidation‐reduction couple with cupric ions in solution. No other common sulfide mineral forms a reversible couple with its cations in solution. For the other minerals of this study, the lack of dependence on rotation implies that diffusion of active species in the electrolyte is not the controlling process. Possible alternate mechanisms include surface controlled processes such as surface diffusion or adsorption phenomena. Ancillary data obtained during this study indicate the interface impedance of chalcopyrite is proportional to the electrode potential which in turn can be controlled by rotation speed, electrolyte composition, or application of an external dc current or voltage. This implies that the surface concentration of active species is dependent on electrode potential.

A High Efficient Baseband GNSS Signal Narrow Band Anti-Jamming Approach in Frequency Domain

2014 ◽  
Vol 926-930 ◽  
pp. 1857-1860
Author(s):  
Zhou Zheng ◽  
Meng Yuan Li ◽  
Wei Jiang Wang
Keyword(s):  
Signal Processing ◽  
Frequency Domain ◽  
Narrow Band ◽  
Low Frequency ◽  
Frequency Resolution ◽  
Interference Rejection ◽  
High Efficient ◽  
Digital Down Conversion ◽  
Down Conversion ◽  
Low Rate

In order to reduce the burden of the calculation and the low frequency resolution of the tradition GNSS signal intermediate narrow band anti-jamming method, it introduces a high efficient approach of narrow band interference rejection based on baseband GNSS signal processing. After digital down conversion to baseband and down sampling to a low rate, the interference is removed in frequency domain. According to the theoretical analysis and simulation, it claims that the method can reduce the calculation and increase the detection resolution in frequency domain which will realize a high efficient interference rejection.

A Systematic Optimization Design Method for Thermal Management of Passenger Vehicles

2021 ◽  
pp. 1-27
Author(s):  
Jie Zhang ◽  
Qidong Wang ◽  
Han Zhang ◽  
Min Zhang ◽  
Jianwei Lin
Keyword(s):  
Prediction Model ◽  
Surface Temperature ◽  
Thermal Management ◽  
Optimization Design ◽  
Cfd Simulation ◽  
Optimal Solution ◽  
Optimization Method ◽  
Drive Shaft ◽  
Management Problem ◽  
Systematic Optimization

Abstract In this study, a systematic optimization method for the thermal management problem of passenger vehicle was proposed. This article addressed the problem of the drive shaft sheath surface temperature exceeded allowable value. Initially, the causes and initial measures of the thermal problem were studied through computational fluid dynamics (CFD) simulation. Furthermore, the key measures and the relevant parameters were determined through Taguchi method and significance analysis. A prediction model between the parameters and optimization objective was built by radial basis function neural network (RBFNN). Finally, the prediction model and particle swarm optimization (PSO) algorithm were combined to calculate the optimal solution, and the optimal solution was selected for simulation and experiment verification. Experiment results indicated that this method reduced the drive shaft sheath surface temperature promptly, the decreasing amplitude was 22%, which was met the experimental requirements.

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