scholarly journals Biomimicry-Gradient-Based Algorithm as Applied to Photonic Devices Design: Inverse Design of Flat Plasmonic Metalenses

2021 ◽  
Vol 11 (12) ◽  
pp. 5436
Author(s):  
Kofi Edee
Keyword(s):  
High Performance ◽  
Figure Of Merit ◽  
Initial Conditions ◽  
Design Method ◽  
Optimal Solution ◽  
High Energy ◽  
Inverse Design ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Efficient Design

The classical adjoint-based topology optimization (TO) method, based on the use of a random continuous dielectric function as design variable distribution is known to be one of the timely efficient and fast optimization methods enable a very high performance functional optical devices. It relies on the computation of the gradient of a figure of merit (FOM) with respect to the design parameters. The gradient of the figure of merit (FOM) may then be used to update the design vector element in several senarios. One of the most common use scenarios consists of updating simultaneously all the design parameter vector elements. In a linear problem case involving a simply convex FOM-function shape, using the gradient information, it is a relatively easy to reach an optimal solution. In the case of constrained and non linear problems stated in an infinite and indeterminate design space, the conventional TO, a local optimizer, may require multiple restarts, with multiple initial points and multiple runs. The algorithm strongly depends on the initial conditions. In this paper, we report a global-like optimizer inspired by a wolf pack hunting, enabling efficient design of metasurfaces through their geometrical parameters. We apply the method to design a non periodic metasurface consisting of plasmonic metalenses, enabling a high energy flow focusing on a well-defined 2D focus spot. Numerical results show that the proposed inverse design method has a low sensitivity to initial conditions. In our design method of metalens, we optimize the full micro device at once, and demonstrate that the proposed method may provide both symmetric and more creative unexpected asymmetric on-axis metalenses even though under a normal illumination.

Redesign of a Transonic Compressor Rotor by Means of a Three-Dimensional Inverse Design Method: A Parametric Study

2007 ◽  
Author(s):  
Duccio Bonaiuti ◽  
Abeetha Pitigala ◽  
Mehrdad Zangeneh ◽  
Yansheng Li
Keyword(s):  
Design Method ◽  
Thickness Distribution ◽  
Three Dimensional ◽  
Tip Clearance ◽  
Inverse Design ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Blade Loading ◽  
Inverse Design Method ◽  
The Impact

In the present paper, the redesign of a transonic rotor was performed by means of a three-dimensional viscous inverse design method. The inverse approach used in this work is one where the pressure loading, blade thickness distribution and stacking axis are specified and the camber surface is calculated accordingly. The design of transonic and supersonic axial compressors strongly relies on the ability to control the shock strength, location and structure. The use of an inverse design method allows one to act directly on aerodynamic parameters, like the blade loading, and provides an efficient tool to control the shock wave and its interaction with the boundary and secondary flows and with the tip clearance vortex. In the present study, the parametric investigation of the blade loading distribution was carried out. Few design parameters, with immediate physical meaning, were required to control the three-dimensional blade loading, and their impact on the design and off-design performance of the rotor was assessed by means of CFD calculations. Further investigations were then performed in order to study the impact on the rotor performance of the geometrical parameters (meridional channel and thickness distribution), which must be imposed in the design with the inverse method. As a result, it was possible to develop guidelines for the aerodynamic design of transonic rotors that can be exploited for similar design applications.

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.

Hydrodynamic Design System for Pumps Based on 3-D CAD, CFD, and Inverse Design Method

2002 ◽  
Vol 124 (2) ◽  
pp. 329-335 ◽  
Author(s):  
Akira Goto ◽  
Motohiko Nohmi ◽  
Takaki Sakurai ◽  
Yoshiyasu Sogawa
Keyword(s):  
Computer Aided Design ◽  
High Performance ◽  
Design Method ◽  
High Reliability ◽  
Secondary Flows ◽  
System Structure ◽  
Inverse Design ◽  
Design System ◽  
Centrifugal Impeller ◽  
Inverse Design Method

A computer-aided design system has been developed for hydraulic parts of pumps including impellers, bowl diffusers, volutes, and vaned return channels. The key technologies include three-dimensional (3-D) CAD modeling, automatic grid generation, CFD analysis, and a 3-D inverse design method. The design system is directly connected to a rapid prototyping production system and a flexible manufacturing system composed of a group of DNC machines. The use of this novel design system leads to a drastic reduction of the development time of pumps having high performance, high reliability, and innovative design concepts. The system structure and the design process of “Blade Design System” and “Channel Design System” are presented. Then the design examples are presented briefly based on the previous publications, which included a centrifugal impeller with suppressed secondary flows, a bowl diffuser with suppressed corner separation, a vaned return channel of a multistage pump, and a volute casing. The results of experimental validation, including flow fields measurements, were also presented and discussed briefly.

scholarly journals Three-Dimensional Inverse Design Method for Hydraulic Machinery

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3210
Author(s):  
Wei Yang ◽  
Benqing Liu ◽  
Ruofu Xiao
Keyword(s):  
High Performance ◽  
Design Method ◽  
Three Dimensional ◽  
Inverse Design ◽  
Blade Loading ◽  
Hydraulic Machinery ◽  
Main Challenge ◽  
Blade Shape ◽  
Stacking Condition ◽  
Inverse Design Method

Hydraulic machinery with high performance is of great significance for energy saving. Its design is a very challenging job for designers, and the inverse design method is a competitive way to do the job. The three-dimensional inverse design method and its applications to hydraulic machinery are herein reviewed. The flow is calculated based on potential flow theory, and the blade shape is calculated based on flow-tangency condition according to the calculated flow velocity. We also explain flow control theory by suppression of secondary flow and cavitation based on careful tailoring of the blade loading distribution and stacking condition in the inverse design of hydraulic machinery. Suggestions about the main challenge and future prospective of the inverse design method are given.

Sensitivity enhancement of a folded beam MEMS capacitive accelerometer-based microphone for fully implantable hearing application

2018 ◽  
Vol 63 (6) ◽  
pp. 699-708 ◽  
Author(s):  
Apoorva Dwivedi ◽  
Gargi Khanna
Keyword(s):  
Microelectromechanical Systems ◽  
Bone Structure ◽  
Design Parameters ◽  
Comsol Multiphysics ◽  
Geometrical Parameters ◽  
Efficient Design ◽  
Capacitive Accelerometer ◽  
Biomedical Device ◽  
Device Geometry ◽  
The Stability

Abstract The present work attempts to enhance the sensitivity of a folded beam microelectromechanical systems (MEMS) capacitive accelerometer by optimising the device geometry. The accelerometer is intended to serve as a microphone in the fully implantable hearing application which can be surgically implanted in the middle ear bone structure. For the efficient design of the accelerometer as a fully implantable biomedical device, the design parameters such as size, weight and resonant frequency have been considered. The geometrical parameters are varied to obtain the optimum sensitivity considering the design constraints and the stability of the structure. The optimised design is simulated and verified using COMSOL MULTIPHYSICS 4.2. The stability of the device is ensured using eigenfrequency analysis. Optimised results of the device geometry are presented and discussed. The accelerometer has a sensing area of 1 mm2 and attains a nominal capacitance of 5.3 pF and an optimum sensitivity of 6.89 fF.

An Inverse Design Based Methodology for Rapid 3D Multi-Objective/Multidisciplinary Optimization of Axial Turbines

2011 ◽  
Author(s):  
Pietro Boselli ◽  
Mehrdad Zangeneh
Keyword(s):  
Design Method ◽  
Turbine Blades ◽  
Multidisciplinary Optimization ◽  
Inverse Design ◽  
Design Parameters ◽  
Multi Objective ◽  
Work Distribution ◽  
Blade Shape ◽  
Inverse Design Method ◽  
Axial Turbines

Design of axial turbines, especially LP turbines, poses difficult tradeoffs between requirements of aerodynamic design and structural limitations. In this paper, a methodology is proposed for 3D multi-objective design of axial turbine blades in which a 3D inverse design method is coupled with a multi-objective genetic algorithm. By parameterizing the blade using blade loading parameters, spanwise work distribution and maximum thickness, a large part of the design space can be explored with very few design parameters. Furthermore, the inverse method not only computes the blade shape but also provides accurate 3D inviscid flow information. In the simple multi-disciplinary approach proposed here the different losses in axial turbines such as endwall losses, tip leakage losses and an indication of flow separation are related through well known correlations to the blade surface velocities predicted by the inverse design method. In addition, geometrical features such as throat area, lean angles and airfoil cross sectional area are computed from the blade shape employed during the optimization. Also, centrifugal stresses and bending stresses are related to the blade geometry. The methodology is then applied to the redesign of an LP turbine rotor with the aim of reducing the maximum stresses while maintaining the performance of the rotor. The results are confirmed by using the commercial CFX CFD (Computational Fluid Dynamics) code and Ansys FEA (Finite Element Analysis) codes.

An experience-independent inverse design optimization method of compressor cascade airfoil

2019 ◽  
Vol 233 (4) ◽  
pp. 431-442 ◽  
Author(s):  
Yujie Zhu ◽  
Yaping Ju ◽  
Chuhua Zhang
Keyword(s):  
Design Optimization ◽  
Design Method ◽  
Three Dimensional ◽  
Optimal Solution ◽  
Leading Edge ◽  
Optimization Method ◽  
Inverse Design ◽  
Compressor Cascade ◽  
Suction Surface ◽  
Inverse Design Method

Most of the inverse design methods of turbomachinery experience the shortcoming where the target aerodynamic parameters need to be manually specified depending on the designers’ experience and insight, making the design result aleatory and even deviated from the real optimal solution. To tackle this problem, an experience-independent inverse design optimization method is proposed and applied to the redesign of a compressor cascade airfoil in this study. The experience-independent inverse design optimization method can automatically obtain the target pressure distribution along the cascade airfoil through the genetic algorithm, rather than through the manual specification approach. The shape of cascade airfoil is then solved by the adjoint method. The effectiveness of the experience-independent inverse design optimization method is demonstrated by two inverse design cases of the compressor cascade airfoil, i.e. the inverse design of only the suction surface and the inverse design of both the suction and pressure surfaces. The results show that the proposed inverse design method is capable of significantly improving the aerodynamic performance of the compressor cascade. At the examined flow condition, a thin airfoil profile is beneficial to flow accelerations near the leading edge and flow separation avoidance near the trailing edge. The proposed inverse design method is quite generic and can be extended to the three-dimensional inverse design of advanced compressor blades.

Multiobjective Optimization Design of a Pump–Turbine Impeller Based on an Inverse Design Using a Combination Optimization Strategy

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Wei Yang ◽  
Ruofu Xiao
Keyword(s):  
Response Surface ◽  
Optimization Design ◽  
Design Method ◽  
Inverse Design ◽  
Design Parameters ◽  
Surface Model ◽  
Optimization Strategy ◽  
Pump Turbine ◽  
Combination Optimization ◽  
Final Design

This paper presents an automatic multiobjective hydrodynamic optimization strategy for pump–turbine impellers. In the strategy, the blade shape is parameterized based on the blade loading distribution using an inverse design method. An efficient response surface model relating the design parameters and the objective functions is obtained. Then, a multiobjective evolutionary algorithm is applied to the response surface functions to find a Pareto front for the final trade-off selection. The optimization strategy was used to redesign a scaled pump–turbine. Model tests were conducted to validate the final design and confirm the validity of the design strategy.

On the Coupling of Inverse Design and Optimization Techniques for Turbomachinery Blade Design

2006 ◽  
Author(s):  
Duccio Bonaiuti ◽  
Mehrdad Zangeneh
Keyword(s):  
Mechanical Design ◽  
Design Method ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Optimization Techniques ◽  
Operating Conditions ◽  
Inverse Design ◽  
Design Parameters ◽  
Optimization Strategy ◽  
Design And Optimization

Optimization strategies have been used in recent years for the aerodynamic and mechanical design of turbomachine components. One crucial aspect in the use of such methodologies is the choice of the geometrical parameterization, which determines the complexity of the objective function to be optimized. In the present paper, an optimization strategy for the aerodynamic design of turbomachines is presented, where the blade parameterization is based on the use of a three-dimensional inverse design method. The blade geometry is described by means of aerodynamic parameters, like the blade loading, which are closely related to the aerodynamic performance to be optimized, thus leading to a simple shape of the optimization function. On the basis of this consideration, it is possible to use simple approximation functions for describing the correlations between the input design parameters and the performance ones. The Response Surface Methodology coupled with the Design of Experiments (DOE) technique was used for this purpose. CFD analyses were run to evaluate the configurations required by the DOE to generate the database. Optimization algorithms were then applied to the approximated functions in order to determine the optimal configuration or the set of optimal ones (Pareto front). The method was applied for the aerodynamic redesign of two different turbomachine components: a centrifugal compressor stage and a single-stage axial compressor. In both cases, both design and off-design operating conditions were analyzed and optimized.

Design of Thick Composite Cylinders

1988 ◽  
Vol 110 (3) ◽  
pp. 255-262 ◽  
Author(s):  
A. K. Roy ◽  
S. W. Tsai
Keyword(s):  
Design Method ◽  
Pressure Vessels ◽  
Design Parameters ◽  
Efficient Design ◽  
3 Dimensional ◽  
Layer Sequence ◽  
External Pressures ◽  
Final Design ◽  
Use Efficiency ◽  
Composite Cylinders

A simple and efficient design method for thick composite cylinders is presented. Micromechanics and macromechanics are integrated by simple relations and the integrated micro and macromechanics approach has been adopted to enable the designers to instantly study the sensitivity of the micromechanical variables on the final design. The stress analysis is based on 3-dimensional elasticity by considering the cylinder in the state of generalized plane strain. The analysis for both open-ended (pipes) and closed-ended (pressure vessels) cylinders subjected to internal and external pressures and axial load is presented. The failure of the cylinders is predicted by using a 3-dimensional quadratic failure criterion. A degradation model is used to calculate burst pressures and the calculated burst pressures agree very well with the available experimental results, for both thin and thick cylinders. In optimizing multilayer cylinders, the 3-D quadratic criterion enables one to obtain the optimal layer sequence very easily. It is found that the layer sequence is very critical in optimizing, in particular, thick cylinders. In addition, the design parameters and material use efficiency of multilayer closed cylinders subjected to internal pressure have also been studied.

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