Filtering and Regularization Shape Optimization Techniques for Preliminary Design

2005 ◽  
Author(s):  
Fernass Daoud ◽  
Florian Jurecka ◽  
Kai-Uwe Bletzinger
Keyword(s):  
Shape Optimization ◽  
Optimization Techniques ◽  
Preliminary Design

Optimum Design of Turbomachinery Components: A System Based Design

2000 ◽  
Author(s):  
Somanath Nagendra
Keyword(s):  
Shape Optimization ◽  
Design Optimization ◽  
Numerical Models ◽  
Turbine Blades ◽  
Optimization Procedure ◽  
Response Surfaces ◽  
Optimization Techniques ◽  
Geometric Constraints ◽  
Preliminary Design ◽  
Design Cycle

Abstract The advent of incredibly fast, increased memory computational systems enable a very systematic design integration of complex engineering modules using an integrated system based approach. Rapid turn-around time for investigating new design concepts is a primary force driving design productivity initiatives across industry. A system based integration focusing on tools for rapid design automation and preliminary design, (e.g. Closed Form Solutions, Response Surfaces, Approximate Numerical Models etc), finite element analysis coupled with optimization methods are needed. Numerical design algorithms (e.g. Sensitivity analysis methods, Feasible Direction methods, Genetic Algorithms, Simulated Annealing, Gradient based Algorithms etc.) at the preliminary and detailed design stages, would ensure higher quality designs from the beginning of the product design cycle. Resulting reliable, robust optimum designs from the preliminary design phase would enable to reduce the overall design cycle time. Large-scale engineering systems (like the gas turbine See Figure. 1) often involve many disciplines which are either loosely or tightly coupled to each other due to the multidisciplinary nature of the interactions. Designers have long recognized the need to decompose such systems into a set of smaller more tractable disciplines. This decomposition is usually based either on engineering disciplines or mathematical models governing the system. Narayan et al. [1] developed a multi-disciplinary design optimization procedure for the design of the aerodynamic shape of turbine blades for enhanced performance using shape optimization techniques. A multidisciplinary design optimization procedure for thin-walled high temperature components has been developed and demonstrated on different components Aerodynamic, heat transfer, structural and modal design objectives are integrated along with various constraint on the blade geometry for multidisciplinary shape optimization. The average blade temperature, maximum blade temperature and the blade weight are minimized with aerodynamic, structural, modal and geometric constraints. A methodology for performing mechanical design of turbine blade components is developed and tested.

scholarly journals A Sequential Approach for Aerodynamic Shape Optimization with Topology Optimization of Airfoils

2021 ◽  
Vol 26 (2) ◽  
pp. 34
Author(s):  
Isaac Gibert Martínez ◽  
Frederico Afonso ◽  
Simão Rodrigues ◽  
Fernando Lau
Keyword(s):  
Topology Optimization ◽  
Shape Optimization ◽  
Volume Fraction ◽  
Optimization Techniques ◽  
Free Form ◽  
Aerodynamic Shape Optimization ◽  
Sequential Approach ◽  
Airfoil Surface ◽  
Aerodynamic Shape ◽  
Design Variables

The objective of this work is to study the coupling of two efficient optimization techniques, Aerodynamic Shape Optimization (ASO) and Topology Optimization (TO), in 2D airfoils. To achieve such goal two open-source codes, SU2 and Calculix, are employed for ASO and TO, respectively, using the Sequential Least SQuares Programming (SLSQP) and the Bi-directional Evolutionary Structural Optimization (BESO) algorithms; the latter is well-known for allowing the addition of material in the TO which constitutes, as far as our knowledge, a novelty for this kind of application. These codes are linked by means of a script capable of reading the geometry and pressure distribution obtained from the ASO and defining the boundary conditions to be applied in the TO. The Free-Form Deformation technique is chosen for the definition of the design variables to be used in the ASO, while the densities of the inner elements are defined as design variables of the TO. As a test case, a widely used benchmark transonic airfoil, the RAE2822, is chosen here with an internal geometric constraint to simulate the wing-box of a transonic wing. First, the two optimization procedures are tested separately to gain insight and then are run in a sequential way for two test cases with available experimental data: (i) Mach 0.729 at α=2.31°; and (ii) Mach 0.730 at α=2.79°. In the ASO problem, the lift is fixed and the drag is minimized; while in the TO problem, compliance minimization is set as the objective for a prescribed volume fraction. Improvements in both aerodynamic and structural performance are found, as expected: the ASO reduced the total pressure on the airfoil surface in order to minimize drag, which resulted in lower stress values experienced by the structure.

AN OPTIMIZATION MODEL FOR PRELIMINARY STABILITY AND CONFIGURATION ANALYSES OF SEMI-SUBMERSIBLES

2021 ◽  
Vol 159 (A3) ◽  
Author(s):  
G D Gosain ◽  
R Sharma ◽  
Tae-wan Kim
Keyword(s):  
Optimization Model ◽  
Design Method ◽  
Optimization Techniques ◽  
Design Approach ◽  
Preliminary Design ◽  
Design Environment ◽  
Preliminary Stage ◽  
Steel Weight ◽  
Motion Characteristics ◽  
Almost All

In the modern era of design governed by economics and efficiency, the preliminary design of a semi-submersible is critically important because in an evolutionary design environment new designs evolve from the basic preliminary designs and the basic dimensions and configurations affect almost all the parameters related to the economics and efficiency (e.g. hydrodynamic response, stability, deck load and structural steel weight of the structure, etc.). The present paper is focused on exploring an optimum design method that aims not only at optimum motion characteristics but also optimum stability, manufacturing and operational efficiency. Our proposed method determines the most preferable optimum principal dimensions of a semi-submersible that satisfies the desired requirements for motion performance and stability at the preliminary stage of design. Our proposed design approach interlinks the mathematical design model with the global optimization techniques and this paper presents the preliminary design approach, the mathematical model of optimization. Finally, a real world design example of a semi-submersible is presented to show the applicability and efficiency of the proposed design optimization model at the preliminary stage of design.

scholarly journals Preliminary Sailplane Design Using MDO And Multi-Fidelity Analysis

2021 ◽  
Author(s):  
Chris V. Pilcher
Keyword(s):  
Multidisciplinary Design Optimization ◽  
High Performance ◽  
Vortex Lattice ◽  
Optimization Techniques ◽  
Multidisciplinary Design ◽  
Preliminary Design ◽  
Adaptive Meshing ◽  
Analysis Methods ◽  
And Performance ◽  
Modern Optimization

A multidisciplinary design optimization (MDO) strategy for the preliminary design of a sailplane has been developed. The proposed approach applies MDO techniques and multi-fidelity analysis methods which have seen successful use in many aerospace design applications. A customized genetic algorithm (GA) was developed to control the sailplane optimization that included aerodynamics/stability, structures/weights and balance and, performance/airworthiness disciplinary analysis modules. An adaptive meshing routine was developed to allow for accurate modeling of the aero structural couplinginvolved in wing design, which included a finite element method (FEM) structural solver along with a vortex lattice aerodynamics solver. Empirical equations were used to evaluate basic sailplane performance and airworthiness requirements. This research yielded an optimum design that correlated well with an existing high performance sailplane. The results of this thesis suggest that preliminary sailplane design is a well suited application for modern optimization techniques when coupled with, multi-fidelity analysis methods.

scholarly journals Shape optimization of turbine blades with the integration of aerodynamics and heat transfer

1998 ◽  
Vol 4 (1) ◽  
pp. 21-42 ◽  
Author(s):  
J. N. Rajadas ◽  
A. Chattopadhyay ◽  
N. Pagaldipti ◽  
S. Zhang
Keyword(s):  
Heat Transfer ◽  
Shape Optimization ◽  
Tangential Force ◽  
Turbine Blades ◽  
Leading Edge ◽  
Optimization Techniques ◽  
Multidisciplinary Optimization ◽  
Heat Transfer Analysis ◽  
Maximum Temperature ◽  
Force Coefficient

A multidisciplinary optimization procedure, with the integration of aerodynamic and heat transfer criteria, has been developed for the design of gas turbine blades. Two different optimization formulations have been used. In the first formulation, the maximum temperature in the blade section is chosen as the objective function to be minimized. An upper bound constraint is imposed on the blade average temperature and a lower bound constraint is imposed on the blade tangential force coefficient. In the second formulation, the blade average and maximum temperatures are chosen as objective functions. In both formulations, bounds are imposed on the velocity gradients at several points along the surface of the airfoil to eliminate leading edge velocity spikes which deteriorate aerodynamic performance. Shape optimization is performed using the blade external and coolant path geometric parameters as design variables. Aerodynamic analysis is performed using a panel code. Heat transfer analysis is performed using the finite element method. A gradient based procedure in conjunction with an approximate analysis technique is used for optimization. The results obtained using both optimization techniques are compared with a reference geometry. Both techniques yield significant improvements with the multiobjective formulation resulting in slightly superior design.

A Hybrid Genetic-Direct Search Algorithm for the Shape Optimization of Solid C-Frame Cross-Sections

2000 ◽  
Author(s):  
Ashraf O. Nassef ◽  
Hesham A. Hegazi ◽  
Sayed M. Metwalli
Keyword(s):  
Genetic Algorithms ◽  
Shape Optimization ◽  
Cross Section ◽  
Random Search ◽  
Direct Search ◽  
Search Method ◽  
Optimization Techniques ◽  
Hybrid Optimization ◽  
The Cross ◽  
Real Coded Genetic Algorithms

Abstract The hybridization of different optimization methods have been used to find the optimum solution of design problems. While random search techniques, such as genetic algorithms and simulated annealing, have a high probability of achieving global optimality, they usually arrive at a near optimal solution due to their random nature. On the other hand direct search methods are efficient optimization techniques but linger in local minima if the objective function is multi-modal. This paper presents the optimization of C-frame cross-section using a hybrid optimization algorithm. Real coded genetic algorithms are used as a random search method, while Nelder-Mead is used as a direct search method, where the result of the genetic algorithm search is used as the starting point of direct search. Traditionally, the cross-section of C-frame belonged to a set of primitive shapes, which included I, T, trapezoidal, circular and rectangular sections. The cross-sectional shape is represented by a non-uniform rational B-Splines (NURBS) in order to give it a kind of shape flexibility. The results showed that the use of Nelder-Mead with Real coded Genetic Algorithms has been very significant in improving the optimum shape of a solid C-frame cross-section subjected to a combined tension and bending stresses. The hybrid optimization method could be extended to more complex shape optimization problems.

Shape Optimization of a Laidback Fan-Shaped Film-Cooling Hole to Enhance Cooling Performance

2010 ◽  
Author(s):  
Ki-Don Lee ◽  
Kwang-Yong Kim
Keyword(s):  
Shape Optimization ◽  
Film Cooling ◽  
Computational Cost ◽  
Latin Hypercube Sampling ◽  
Surrogate Models ◽  
Optimization Techniques ◽  
Film Cooling Effectiveness ◽  
Injection Angle ◽  
Expansion Angle ◽  
Cooling Hole

Shape optimization of a laidback fan-shaped film-cooling hole has been performed by surrogate-based optimization techniques using three-dimensional Reynolds-averaged Navier-Stokes analysis. Spatially-averaged film-cooling effectiveness has been maximized for the optimization. The injection angle of the hole, the lateral expansion angle of the diffuser, the forward expansion angle of the hole, and the ratio of the length to the diameter of the hole are chosen as design variables, and thirty-five experimental points within design space are selected by Latin hypercube sampling. Basic surrogate models, such as second-order polynomial response approximation (RSA), Kriging meta-modeling technique, radial basis neural network (RBNN), are constructed using the analysis results, and the PBA model is composed from these basic surrogate models with the weights being calculated for each basic surrogate. The optimal points are searched from the above constructed surrogates by sequential programming (SQP). It is shown that use of multiple surrogates increases the robustness in prediction of better design with minimum computational cost.

Transonic Airfoil Shape Optimization in Preliminary Design Environment

2006 ◽  
Vol 43 (3) ◽  
pp. 639-651 ◽  
Author(s):  
W. Li ◽  
S. Krist ◽  
R. Campbell
Keyword(s):  
Shape Optimization ◽  
Preliminary Design ◽  
Design Environment ◽  
Transonic Airfoil

An Energy Formulation for Parametric Size and Shape Optimization of Compliant Mechanisms

1999 ◽  
Vol 121 (2) ◽  
pp. 229-234 ◽  
Author(s):  
J. A. Hetrick ◽  
S. Kota
Keyword(s):  
Shape Optimization ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Optimization Procedure ◽  
Stress Constraints ◽  
Optimization Techniques ◽  
Mechanical Transmission ◽  
Dimensional Synthesis ◽  
Size And Shape ◽  
Mechanical Devices

Compliant mechanisms are jointless mechanical devices that take advantage of elastic deformation to achieve a force or motion transformation. An important step toward automated design of compliant mechanisms has been the development of topology optimization techniques. The next logical step is to incorporate size and shape optimization to perform dimensional synthesis of the mechanism while simultaneously considering practical design specifications such as kinematic and stress constraints. An improved objective formulation based on maximizing the energy throughput of a linear static compliant mechanism is developed considering specific force and displacement operational requirements. Parametric finite element beam models are used to perform the size and shape optimization. This technique allows stress constraints to limit the maximum stress in the mechanism. In addition, constraints which restrict the kinematics of the mechanism are successfully applied to the optimization problem. Resulting optimized mechanisms exhibit efficient mechanical transmission and meet kinematic and stress requirements. Several examples are given to demonstrate the effectiveness of the optimization procedure.

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