Freeform Deformation Versus B-Spline Representation in Inverse Airfoil Design

2008 ◽  
Vol 8 (2) ◽  
Author(s):  
Eleftherios I. Amoiralis ◽  
Ioannis K. Nikolos
Keyword(s):  
Three Dimensional ◽  
Differential Evolution Algorithm ◽  
3D Animation ◽  
B Spline ◽  
Spline Curves ◽  
Design Variables ◽  
Evolution Algorithm ◽  
Freeform Deformation ◽  
Reference Pressure ◽  
Insight Into

Freeform deformation (FFD) is a well established technique for 3D animation applications, used to deform two—or three-dimensional geometrical entities. Over the past few years, FFD technique has aroused growing interest in several scientific communities. In this work, an extensive bibliographic survey of the FFD technique is initially introduced, in order to explore its capabilities in shape parametrization. Moreover, FFD technique is compared to the classical parametrization technique using B-spline curves, in the context of the airfoil design optimization problem, by performing inverse airfoil design tests, with a differential evolution algorithm to serve as the optimizer. The criterion of the comparison between the two techniques is the achieved accuracy in the approximation of the reference pressure distribution. Experiments are presented, comparing FFD to B-spline techniques under the same flow conditions, for various numbers of design variables. Sensitivity analysis is applied for providing further insight into the differences in the performance of the two techniques.

Freeform Deformation vs. B-Spline Representation in Inverse Airfoil Design

2006 ◽  
Author(s):  
Eleftherios I. Amoiralis ◽  
Ioannis K. Nikolos
Keyword(s):  
Differential Evolution ◽  
Optimization Algorithm ◽  
Flow Conditions ◽  
B Spline ◽  
De Algorithm ◽  
Spline Curves ◽  
Design Variables ◽  
Spline Representation ◽  
Freeform Deformation ◽  
Reference Pressure

In this work FFD technique is compared to the classical parameterization technique using B-Spline curves by performing inverse airfoil design tests, with a Differential Evolution (DE) algorithm to serve as the optimizer. The criteria of the comparison between the two techniques are the achieved accuracy in the approximation of the reference pressure distribution and the convergence behavior of the optimization algorithm. Experiments are presented, comparing FFD to B-Spline techniques under the same flow conditions, for various numbers of design variables.

Frequency optimization of laminated functionally graded carbon nanotube reinforced composite quadrilateral plates using smoothed FEM and evolution algorithm

2017 ◽  
Vol 52 (14) ◽  
pp. 1971-1986 ◽  
Author(s):  
T Vo-Duy ◽  
T Truong-Thi ◽  
V Ho-Huu ◽  
T Nguyen-Thoi
Keyword(s):  
Carbon Nanotube ◽  
Optimization Problem ◽  
Volume Fraction ◽  
Differential Evolution Algorithm ◽  
Composite Plates ◽  
Functionally Graded ◽  
Optimization Approach ◽  
Reinforced Composite ◽  
Design Variables ◽  
Evolution Algorithm

The paper presents an efficient numerical optimization approach to deal with the optimization problem for maximizing the fundamental frequency of laminated functionally graded carbon nanotube-reinforced composite quadrilateral plates. The proposed approach is a combination of the cell-based smoothed discrete shear gap method (CS-DSG3) for analyzing the first natural frequency of the functionally graded carbon nanotube reinforced composite plates and a global optimization algorithm, namely adaptive elitist differential evolution algorithm (aeDE), for solving the optimization problem. The design variables are the carbon nanotube orientation in the layers and constrained in the range of integer numbers belonging to [−900 900]. Several numerical examples are presented to investigate optimum design of quadrilateral laminated functionally graded carbon nanotube reinforced composite plates with various parameters such as carbon nanotube distribution, carbon nanotube volume fraction, boundary condition and number of layers.

scholarly journals Formulation and Solution of an Inverse Reliability Problem to Simulate the Dynamic Behavior of COVID-19 Pandemic

2021 ◽  
Vol 22 (1) ◽  
pp. 91-107
Author(s):  
F. S. Lobato ◽  
G. M. Platt ◽  
G. B. Libotte ◽  
A. J. Silva Neto
Keyword(s):  
Dynamic Behavior ◽  
Differential Evolution Algorithm ◽  
Iteration Process ◽  
Real Data ◽  
The Novel ◽  
Design Variables ◽  
Different Types ◽  
Evolution Algorithm ◽  
Novel Coronavirus ◽  
Optimization Loop

Different types of mathematical models have been used to predict the dynamic behavior of the novel coronavirus (COVID-19). Many of them involve the formulation and solution of inverse problems. This kind of problem is generally carried out by considering the model, the vector of design variables, and system parameters as deterministic values. In this contribution, a methodology based on a double loop iteration process and devoted to evaluate the influence of uncertainties on inverse problem is evaluated. The inner optimization loop is used to find the solution associated with the highest probability value, and the outer loop is the regular optimization loop used to determine the vector of design variables. For this task, we use an inverse reliability approach and Differential Evolution algorithm. For illustration purposes, the proposed methodology is applied to estimate the parameters of SIRD (Susceptible-Infectious-Recovery-Dead) model associated with dynamic behavior of COVID-19 pandemic considering real data from China's epidemic and uncertainties in the basic reproduction number (R0). The obtained results demonstrate, as expected, that the increase of reliability implies the increase of the objective function value.

scholarly journals Optimization of modular and helical coils applying genetic algorithm and fully-three-dimensional B-spline curves

2021 ◽  
Author(s):  
Hiroyuki Yamaguchi ◽  
Shinsuke Satake ◽  
Motoki Nakata ◽  
Akihiro Shimizu ◽  
Yasuhiro Suzuki
Keyword(s):  
Genetic Algorithm ◽  
Three Dimensional ◽  
B Spline ◽  
Spline Curves ◽  
Helical Coils

Optimization of a Centrifugal Impeller Using Evolutionary Algorithms

2008 ◽  
Author(s):  
Andreas Bartold ◽  
Franz Joos
Keyword(s):  
Evolutionary Algorithms ◽  
Three Dimensional ◽  
Optimization Method ◽  
Navier Stokes ◽  
Centrifugal Impeller ◽  
Aerodynamic Design ◽  
B Spline ◽  
Spline Curves ◽  
Automated Optimization ◽  
Isentropic Efficiency

This paper presents the development and application of an automated optimization method for aerodynamic design of centrifugal impellers. The algorithm used for the optimization is an evolutionary algorithm. Within this method the shape of the centrifugal impeller is described using B-Spline curves. The method introduced is used for redesigning an existing impeller with regard to maximization of the isentropic efficiency at a fixed operating point. Here the isentropic efficiency is calculated using the solution of a compressible three-dimensional Reynolds-averaged Navier-Stokes solver. The presentation will show that the method presented provides a new design that outperforms the original impeller with respect to the particular objective and demonstrates its usefulness.

scholarly journals Weight optimization of composite cellular beam based on the differential evolution algorithm

2018 ◽  
Vol 12 (5) ◽  
pp. 28-38
Author(s):  
Nguyen Tran Hieu ◽  
Vu Anh Tuan
Keyword(s):  
Differential Evolution ◽  
Design Method ◽  
Minimum Weight ◽  
Differential Evolution Algorithm ◽  
Limit States ◽  
Web Opening ◽  
Design Variables ◽  
Optimal Spacing ◽  
Evolution Algorithm ◽  
Hot Rolled

In this study, the differential evolution algorithm is used for solving the optimum design problem of composite cellular beams. The design variables are hot rolled profile from which the cellular beam will be produced as well as opening size and its spacing. The objective function is the minimum weight of cellular beam while the design constraints include satisfying the ultimate limit states, the serviceability limit states and the geometric limitations. The design method adopted in this study is based on EN 1994-1-1. Furthermore, a parametric study is conducted to evaluate the influence of beams spacing to the weight of floor beam system. As a result, an optimal spacing of composite cellular beams is proposed. Keywords: composite beam; cellular beam; web opening; steel beam optimization; differential evolution.

Gravity Inversion for Heterogeneous Sedimentary Basin with b-Spline Polynomial Approximation using Differential Evolution Algorithm

Geophysics ◽  
2021 ◽  
pp. 1-63
Author(s):  
Arka Roy ◽  
Chandra Prakash Dubey ◽  
M. Prasad
Keyword(s):  
Differential Evolution ◽  
Polynomial Approximation ◽  
Sedimentary Basin ◽  
Differential Evolution Algorithm ◽  
Sedimentary Basins ◽  
B Spline ◽  
Basement Depth ◽  
Evolution Algorithm ◽  
Inversion Techniques ◽  
Spline Polynomial

A MATLAB-based inversion program, b-Spline Polynomial Approximation using Differential Evolution Algorithm (SPODEA), is introduced to recover the concealed basement geometry under heterogeneous sedimentary basins. Earlier inversion techniques used the discretized subsurface interface topography into a grid of juxtaposed elementary prisms to estimate the basement depth of a basin. Such discretization leads to the failure of depth profile continuity and requires a higher number of inversion parameters for achieving the desired accuracy. The novel approach of SPODEA overcomes such limitations of earlier inversion techniques. SPODEA is based on the segment-wise b-spline optimization technique to estimate the basement depth by using high-order polynomials.Moreover, it can achieve an optimal misfit with a minimal parametric information, which reduces the computational expense. The proposed inversion approach uses the differential evolution (DE) algorithm that provides real parametric optimization and uses b-splines for an accurate estimation of continuous depth profiles. The efficiency of the proposed algorithm is illustrated with two complex synthetic sedimentary basin models comprised of constant and depth varying density distributions. Furthermore, the uncertainty analysis of the proposed inversion technique is evaluated by incorporating white Gaussian noise into the synthetic models. Finally, the utility of SPODEA is illustrated by inverting gravity anomalies for two different real sedimentary basins. It produces geologically reasonable outcomes that are in close agreement with basement structures from previously reported results.

Parametric Design and Optimization of Sailing Yachts

1999 ◽  
Author(s):  
Stefan Harries ◽  
Claus Abt
Keyword(s):  
Geometric Modeling ◽  
Parametric Design ◽  
Generation Process ◽  
B Spline ◽  
Design And Optimization ◽  
Spline Curves ◽  
Design Variables ◽  
Hull Forms ◽  
High Level ◽  
Important Form

A new and flexible method for the geometric modeling of ship hull forms is presented. The underlying methodology is the parametric design of B-spline curves and surfaces. Important form parameters like displacement, center of buoyancy, waterplane area, center of flotation etc. are utilized as high-level descriptors of the intended shapes. Instead of interactively manipulating B-spline vertices, the generation process is viewed as a constrained optimization problem where fairness measures are applied as objective functions, vertices are treated as design variables and form parameters are preserved as equality constraints - making the approach a novelty in B­spline modeling. The new design methodology is discussed and mathematical principles are outlined. Examples are given to demonstrate the applicability of the parametric approach. They include the design of a 33ft IMS yacht with focus on the bare hull without rudder and keel.

Analytic and discrete fairing of three-dimensional B-spline curves using nonlinear programming

2007 ◽  
Vol 53 (2) ◽  
pp. 263-269 ◽  
Author(s):  
Hyun Chan Lee ◽  
Seok Yong Hong ◽  
Chung Sung Hong ◽  
Koohyun Park ◽  
Deok-Soo Kim
Keyword(s):  
Nonlinear Programming ◽  
Three Dimensional ◽  
B Spline ◽  
Spline Curves

scholarly journals Optimization of steel roof trusses using machine learning-assisted differential evolution

2021 ◽  
Vol 15 (4) ◽  
pp. 99-110
Author(s):  
Nguyen Tran Hieu ◽  
Nguyen Quoc Cuong ◽  
Vu Anh Tuan
Keyword(s):  
Differential Evolution ◽  
Computational Cost ◽  
Differential Evolution Algorithm ◽  
Truss Structures ◽  
De Algorithm ◽  
Design Variables ◽  
Evolution Algorithm ◽  
Structural Engineers ◽  
Steel Trusses ◽  
Steel Roof

A steel truss is a preferred solution in large-span roof structures due to its good attributes such as lightweight, durability. However, designing steel trusses is a challenging task for engineers due to a large number of design variables. Recently, optimization-based design approaches have demonstrated the great potential to effectively support structural engineers in finding the optimal designs of truss structures. This paper aims to use the AdaBoost-DE algorithm for optimizing steel roof trusses. The AdaBoost-DE employed in this study is a hybrid algorithm in which the AdaBoost classification technique is used to enhance the performance of the Differential Evolution algorithm by skipping unnecessary fitness evaluations during the optimization process. An example of a duo-pitch steel roof truss with a span of 24 meters is carried out. The result shows that the AdaBoost-DE achieves the same optimal design as the original DE algorithm, but reduces the computational cost by approximately 36%.

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