scholarly journals Identification of Material Properties and Optimal Design of Magnetically Shielded Rooms

2021 ◽  
Vol 7 (2) ◽  
pp. 23
Author(s):  
Aldo Canova ◽  
Fabio Freschi ◽  
Luca Giaccone ◽  
Maurizio Repetto ◽  
Luigi Solimene
Keyword(s):  
Magnetic Field ◽  
Magnetic Material ◽  
Optimal Design ◽  
Design Procedure ◽  
Magnetic Characteristic ◽  
Design Parameters ◽  
Ferromagnetic Structure ◽  
Shielding Factor ◽  
The Cost ◽  
Low Magnetic Field

In this paper, we propose an optimal design procedure for magnetically shielded rooms. Focusing on multi-layer ferromagnetic structures, where inner layers operate at very low magnetic field, we propose an identification method of the magnetic material characteristic in the Rayleigh region. A numerical model to simulate the shielding efficiency of a multi-layer ferromagnetic structure is presented and experimentally tested on different geometries and layer configurations. The fixed point iterative method is adopted to handle the nonlinearity of the magnetic material. In conclusion, the optimization of the design parameters of a MSR is discussed, using the Vector Immune System algorithm to minimize the magnetic field inside the room and the cost of the structure. The results highlight that a linear magnetic characteristic for the material is sufficient to identify the suitable geometry of the shield, but the nonlinear model in the Rayleigh region is of fundamental importance to determine a realistic shielding factor.

scholarly journals A Two-Round Optimization Design Method for Aerostatic Spindles Considering the Fluid–Structure Interaction Effect

2021 ◽  
Vol 11 (7) ◽  
pp. 3017
Author(s):  
Qiang Gao ◽  
Siyu Gao ◽  
Lihua Lu ◽  
Min Zhu ◽  
Feihu Zhang
Keyword(s):  
Optimal Design ◽  
Optimization Design ◽  
Design Method ◽  
Fluid Structure Interaction ◽  
Design Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Aerostatic Spindle

The fluid–structure interaction (FSI) effect has a significant impact on the static and dynamic performance of aerostatic spindles, which should be fully considered when developing a new product. To enhance the overall performance of aerostatic spindles, a two-round optimization design method for aerostatic spindles considering the FSI effect is proposed in this article. An aerostatic spindle is optimized to elaborate the design procedure of the proposed method. In the first-round design, the geometrical parameters of the aerostatic bearing were optimized to improve its stiffness. Then, the key structural dimension of the aerostatic spindle is optimized in the second-round design to improve the natural frequency of the spindle. Finally, optimal design parameters are acquired and experimentally verified. This research guides the optimal design of aerostatic spindles considering the FSI effect.

Optimal Design of Underwater Shells With Active Stiffeners

2001 ◽  
Author(s):  
W. Akl ◽  
M. Ruzzene ◽  
A. Baz
Keyword(s):  
Optimal Design ◽  
Low Cost ◽  
Element Model ◽  
Design Parameters ◽  
Optimization Approach ◽  
Noise Radiation ◽  
Stiffened Shells ◽  
Shell Vibration ◽  
The Cost ◽  
Controllability And Observability

Abstract The optimal design parameters of fluid-loaded shells, provided with actively controlled stiffeners, are determined using a rational multi-criteria optimization approach. The adopted approach aims at simultaneously minimizing the shell vibration, associated sound radiation, weight of the stiffening rings, the control energy, and the cost of the shell/stiffeners assembly while maximizing the controllability and observability indices. A finite element model is presented to predict the vibration and noise radiation from cylindrical shells, with active stiffeners, into the surrounding fluid domain. The production cost as well as the life cycle and maintenance costs of the stiffened shells are computed using the Parametric Review of Information for Costing and Evaluation (PRICE) model. A Pareto/min-max multi-criteria optimization approach is then utilized to select the optimal locations and dimensions of the active stiffeners. Numerical examples are presented to compare the vibration and noise radiation characteristics of me optimally designed/controlled stiffened shells with the corresponding characteristics of plain un-stiffened and uncontrolled shells. The obtained results emphasize me importance of the adopted multi-criteria optimization approach in the design of quiet, low weight and low cost underwater shells which are suitable for various critical applications.

scholarly journals Optimal Design of Rated Wind Speed and Rotor Radius to Minimizing the Cost of Energy for Offshore Wind Turbines

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2728 ◽  
Author(s):  
Longfu Luo ◽  
Xiaofeng Zhang ◽  
Dongran Song ◽  
Weiyi Tang ◽  
Jian Yang ◽  
...  
Keyword(s):  
Wind Speed ◽  
Optimal Design ◽  
Wind Energy ◽  
Wind Turbines ◽  
Offshore Wind ◽  
Design Parameters ◽  
Offshore Wind Energy ◽  
Offshore Wind Turbines ◽  
Cost Of Energy ◽  
The Cost

As onshore wind energy has depleted, the utilization of offshore wind energy has gradually played an important role in globally meeting growing green energy demands. However, the cost of energy (COE) for offshore wind energy is very high compared to the onshore one. To minimize the COE, implementing optimal design of offshore turbines is an effective way, but the relevant studies are lacking. This study proposes a method to minimize the COE of offshore wind turbines, in which two design parameters, including the rated wind speed and rotor radius are optimally designed. Through this study, the relation among the COE and the two design parameters is explored. To this end, based on the power-coefficient power curve model, the annual energy production (AEP) model is designed as a function of the rated wind speed and the Weibull distribution parameters. On the other hand, the detailed cost model of offshore turbines developed by the National Renewable Energy Laboratory is formulated as a function of the rated wind speed and the rotor radius. Then, the COE is formulated as the ratio of the total cost and the AEP. Following that, an iterative method is proposed to search the minimal COE which corresponds to the optimal rated wind speed and rotor radius. Finally, the proposed method has been applied to the wind classes of USA, and some useful findings have been obtained.

An Integrated Approach for Friction Damper Design

1990 ◽  
Vol 112 (2) ◽  
pp. 175-182 ◽  
Author(s):  
T. M. Cameron ◽  
J. H. Griffin ◽  
R. E. Kielb ◽  
T. M. Hoosac
Keyword(s):  
Optimal Design ◽  
High Speed ◽  
Design Procedure ◽  
Single Mode ◽  
Design Parameters ◽  
Bench Test ◽  
Friction Damper ◽  
Friction Dampers ◽  
Damper Design ◽  
Blade Model

A procedure is outlined for determining the optimal design of friction dampers for high-speed turbomachinery blading. The procedure includes: An integration of bench test results with finite-element analysis and a single-mode blade model to ensure accuracy of the analytical model and improve reliability of the friction damper design; an extension of the single-mode blade model to predict the engine behavior of friction dampers; and a new way of viewing analytical and experimental results in terms of a damper performance curve to determine optimal design parameters, when the levels of excitation and damping in the system are unknown. Unique experiments are performed on a test disk in order to demonstrate and verify the accuracy of the design procedure.

scholarly journals A Simulation Study for the Design of Membrane Restrictor in an Opposed-Pad Hydrostatic Bearing to Achieve High Static Stiffness

Lubricants ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 71
Author(s):  
Ta-Hua Lai ◽  
Shih-Chieh Lin
Keyword(s):  
Optimal Design ◽  
Design Procedure ◽  
Effective Area ◽  
Design Parameters ◽  
Static Stiffness ◽  
Load Range ◽  
Hydrostatic Bearing ◽  
Optimal Value ◽  
Bearing Stiffness ◽  
Design Restriction

The effects of a membrane restrictor’s design parameters on the performance of a hydrostatic opposed-pad bearing are presented in this article. Compared to the single-pad bearing, the opposed-pad bearing can perform much better in terms of static stiffness over a wider load range. It is also found that, for small bearing eccentricity, the optimal design restriction ratio of 0.25 still results in high bearing stiffness even if the dimensionless stiffness of membrane is not the optimal value of 1.33. Furthermore, decreasing the ratio of the upper effective area to the lower effective area generally increases the applicable working range of the bearing. Additionally, for high loading demands, the chance for further improvement of bearing performance by employing different design parameter for each pad is examined. Finally, a design procedure for designing the membrane restrictor for an opposed-pad bearing to achieve high static stiffness is given.

Optimal Design of a Parallel Micromanipulator for Precision Machining

2009 ◽  
Vol 69-70 ◽  
pp. 590-594
Author(s):  
Z.F. Wang ◽  
Guan Wang ◽  
Shi Ming Ji ◽  
J.H. Sun
Keyword(s):  
Optimal Design ◽  
Search Algorithm ◽  
Design Procedure ◽  
Pattern Search ◽  
Design Parameters ◽  
Precision Machining ◽  
Pattern Search Algorithm ◽  
Generalized Pattern Search ◽  
Precision And Accuracy ◽  
Design Result

A parallel micromanipulator (PmM) which can be applied into the precision machining is optimized in the paper. This paper adopts a methodology to determine a set of optimal design parameters of PmM whose workspace is as close as possible of being equal to a prescribed cuboid dexterous workspace (PCDW). The kinematic problem is analyzed in brief to determine the design parameters and their relation. Then, an optimal design procedure which adopts the generalized pattern search algorithm in the genetic algorithm and direct search toolbox of Matlab is proposed to solve these problems. As an applying example, the results of four cases PCDW to PmM are presented. And the design result is compared with a concept of the distance between the best state of the PmM and the requirement of the operation task. The method and result of this paper are very useful for the design of micromanipulator for the machining field which requires the high precision and accuracy.

Flower pollination-based optimal design of reinforced concrete beams with externally bonded of FRPS

2020 ◽  
Vol 29 ◽  
pp. 2633366X2096249
Author(s):  
N Sundar ◽  
PN Raghunath ◽  
G Dhinakaran
Keyword(s):  
Reinforced Concrete ◽  
Optimal Design ◽  
Concrete Beams ◽  
Weight Ratio ◽  
Design Procedure ◽  
Reinforced Concrete Beams ◽  
Design Parameters ◽  
Flower Pollination ◽  
Reinforced Polymer ◽  
Externally Bonded

The optimal design of reinforced concrete beams (RCBs) and structures with an objective of improving the chosen performances is an important problem in the field of construction works. Recently, the concrete beams, structures, and walls are strengthened externally by bonding fiber-reinforced polymer strips (FRPS). Usually, FRPS are employed in rehabilitation of existing beams, bridges, and other structural elements. This article modifies the problem of designing new RCBs with appropriate selection of FRPS with a goal of exploiting the benefits of FRPS such as higher tensile strength, better corrosion resistance, higher stiffness-to-weight ratio, and longer life. It, firstly, proposes an artificial neural network-based mathematical model for assessing the performances of RCBs bonded with FRPS from the data obtained from 69 FRPS-glued RCBs and then develops an optimal design procedure employing flower pollination-based optimization, which is imitated from the pollination process of plants, for obtaining design parameters of FRPS-glued RCBs with a view of enhancing both the ultimate load and the deflection ductility. It presents optimal design parameters of five FRPS-glued RCBs and experimentally validates the performances.

scholarly journals Optimal design of fixture layouts for compliant sheet metal assemblies

2020 ◽  
Vol 110 (7-8) ◽  
pp. 2181-2201
Author(s):  
Abolfazl Rezaei Aderiani ◽  
Kristina Wärmefjord ◽  
Rikard Söderberg ◽  
Lars Lindkvist ◽  
Björn Lindau
Keyword(s):  
Optimal Design ◽  
Sheet Metal ◽  
Design Procedure ◽  
Optimization Method ◽  
Design Parameters ◽  
Fixture Layout ◽  
Geometrical Quality ◽  
Evolutionary Optimization Algorithms ◽  
Assembly Procedure

Abstract A preeminent factor in the geometrical quality of a compliant sheet metal assembly is the fixture layout that is utilized to perform the assembly procedure. Despite the presence of a great number of studies about the optimization of assembly fixture layouts, there is not a comprehensive algorithm to optimize all design parameters of fixture layouts for compliant sheet metal assemblies. These parameters are the location and type of hole and slot in each part, the slot orientation, and the number and location of additional clamps. This paper presents a novel optimization method that optimizes all these parameters simultaneously to maximize the geometrical quality of the assemblies. To attain this goal, compliant variation simulations of the assemblies are utilized along with evolutionary optimization algorithms. The assembly springback and contacts between parts are considered in the simulations. After determining the optimal design parameters, the optimal positions of locators are fine-tuned in another stage of optimization. Besides, a top-down design procedure is proposed for applying this method to multi-station compliant assemblies. The presented method is applied to two industrial sample cases from the automotive industry. The results evidence a significant improvement of geometrical quality by utilizing the determined fixture layout from the presented method compared with the original fixture layouts of the sample cases.

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