Topology Optimization of an Aircraft Component as a Fluid-Structure - - PowerPoint PPT Presentation

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Topology Optimization of an Aircraft Component as a Fluid-Structure - - PowerPoint PPT Presentation

Nov 24, 2022 376 likes •660 views

Topology Optimization of an Aircraft Component as a Fluid-Structure System with Unstructured Mesh Walter J. Paucar Casas 1 , Emanuel M. Cesconeto 2 , Ederval de S. Lisboa, Joo B. D. Moreira, Jos E. Medeiros and Thomas S. Ribeiro 1 Presenter

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Topology Optimization of an Aircraft Component as a Fluid-Structure System with Unstructured Mesh

Walter J. Paucar Casas1, Emanuel M. Cesconeto2, Ederval de S. Lisboa, João B. D. Moreira, José E. Medeiros and Thomas S. Ribeiro

1 Presenter and corresponding author: walter.paucar.casas@ufrgs.br 2 Corresponding author: emanuelEMC@hotmail.com

Mechanical Engineering Department Mechanical Engineering Department, Federal University of Rio Grande do Sul, Sarmento Leite 425, 90050-170, Porto Alegre/RS, Brazil

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Contents

  • 1 – Introduction
  • 2 – Objectives
  • 3 – Justification
  • 4 – Methodology
  • 5 – Results
  • 6 – Conclusion

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TOPOLOGY OPTIMIZATION FLUID-STRUCTURE SYSTEM WITH UNSTRUCTURED MESH

1 - Introduction

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TOPOLOGY OPTIMIZATION DE UM SISTEMA FLUIDO-ESTRUTURA COM MALHA NÃO ESTRUTURADA

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TOPOLOGY OPTIMIZATION

Solid structure, with too much unnecessary material Less loaded material removed: structure optimized

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TOPOLOGY OPTIMIZATION

1 2 3

1 2 3 Material volume Stiffness

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TOPOLOGY OPTIMIZATION

  • Part of the design of a structure
  • Generation of an optimized concept
  • Then it needs to be converted to CAD
  • Depends on the problem definition
  • Domain that can be occupied by the structure
  • Loads and boundary conditions
  • Seeks the best possible characteristics of a structure that uses

less material

  • Reduces weight and potentially costs
  • Final characteristics may be worse than the ones found in the original structure

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TOPOLOGY OPTIMIZATION FLUID-STRUCTURE SYSTEM COM MALHA NÃO ESTRUTURADA

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TOPOLOGY OPTIMIZATION FLUID-STRUCTURE SYSTEM COM MALHA NÃO ESTRUTURADA

Fluid Structure Fluid Structure Empty space

The fluid applies forces on the structure due to its pressure

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TOPOLOGY OPTIMIZATION FLUID-STRUCTURE SYSTEM COM MALHA NÃO ESTRUTURADA

Movable boundaries Fixed boundaries

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TOPOLOGY OPTIMIZATION FLUID-STRUCTURE SYSTEM COM MALHA NÃO ESTRUTURADA

  • Optimization method described in the literature: BEFSO
  • Bi-directional Evolutionary Fluid-Structure Optimization

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(also irregular)

TOPOLOGY OPTIMIZATION FLUID-STRUCTURE SYSTEM WITH UNSTRUCTURED MESH

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TOPOLOGY OPTIMIZATION FLUID-STRUCTURE SYSTEM WITH UNSTRUCTED MESH

(also irregular)

Structured Unstructured Regular Irregular

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TOPOLOGY OPTIMIZATION FLUID-STRUCTURE SYSTEM WITH UNSTRUCTED MESH

(also irregular)

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2 - Objectives

  • Modify the BEFSO topology optimization

method to obtain this functionality

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3 - Justification

  • Build upon the topology optimization method,

so it can be used in cases with more complex geometry using less elements

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4 - Methodology

Start

Problem formulation Current structure configuration FEM analysis Initial sensibility calculation Filtering of the sensibility Structure modification

Current desired volume of the structure Reduction of the structure volume, due to the evolution rate

Current volume equals the desired volume?

No No No Yes Yes

Stop criteria satisfied?

Final structure configuration

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Definition of the domain and boundary conditions

4 - Methodology

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Mesh generation

4 - Methodology

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FEM analysis

4 - Methodology

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Calculation of the sensibility (contribution) of each element

4 - Methodology

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Filtering of the sensibility values

4 - Methodology

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New structure with less material, without the elements with the lowest contributing elements

4 - Methodology

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Several iterations until the final structure

4 - Methodology

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5 - Results

a) Result found by Vicente (2013)* b) Result achieved with 8375 elements

Half piston Regular mesh Movable F-S interface

* Vicente, W.M. 2013 Otimização Topológica Evolucionária Aplicada a Sistemas Elasto-Acústicos. Doctoral Thesis in Mechanical Engineering, Campinas State University, Campinas, SP, Brazil.

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5 - Results

Flow Velocity U 200 km/h (55.57 m/s) Air density air 1.007 kg/m3 Dynamic pressure q 1554.0 Pa Altitude H 2000 m Wing profile NACA 4412 Angle of attack A 13º57’ Chord c 2 m Thickness of the fixed interface layer T 10 mm Number of elements n 15790 NACA 4412 profile with an angle of attack of 13°57’ Optimization of internal cross structure of an airplane wing. In this case, there is a fixed interface between the fluid and the structure, because the external profile of the wing is determined by its aerodynamic behavior that is not simulated here. The distribution of external pressure caused by air during its operation is given by Allen (1939)*, function of the dynamic pressure.

* Allen, H.J. 1939 A Simplified Method for the Calculation of Airfoil Pressure Distribution. Langley Aeronautical Lab., Langley Field, VA, USA, NACA-TN- 708, 17p

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5 - Results

Results for optimization of the internal structural cross section in a wing profile NACA

  • 4412. The colored regions represent the fluid with the fringe indicating the pressure
  • levels. The gray circular region represents a beam perpendicular to image, where the

fixed conditions are applied

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6 - Conclusions

 The developed software was capable to optimize cases with

unstructured and irregular meshes, and with or without movable interface.  It was possible to implement the topology optimization code BEFSO without any dependence on external commercial

  • programs. As example, one aircraft wing was optimized using an

unstructured and irregular mesh.

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