scholarly journals Applying Multiobjective Cost and Weight Optimization to the Initial Design of Turbine Disks

2007 ◽  
Vol 129 (12) ◽  
pp. 1303-1310 ◽  
Author(s):  
A. R. Rao ◽  
J. P. Scanlan ◽  
A. J. Keane
Keyword(s):  
Fatigue Life ◽  
Minimum Weight ◽  
Minimum Cost ◽  
Aircraft Engine ◽  
Integrated System ◽  
Structural Performance ◽  
Manufacturing Cost ◽  
Optimization Approach ◽  
Element Analysis ◽  
Conflicting Objectives

Aerospace design optimization typically explores the effects of structural performance and aerodynamics on the geometry of a component. This paper presents a methodology to incorporate manufacturing cost and fatigue life models within an integrated system to simultaneously trade off the conflicting objectives of minimum weight and manufacturing cost while satisfying constraints placed by structural performance and fatigue. A case study involving the design of a high pressure turbine disk from an aircraft engine is presented. Manufacturing cost and fatigue life models are developed in DECISIONPRO™, a generic modeling tool, whereas finite element analysis is carried out in the Rolls-Royce PLC proprietary solver SC03. A multiobjective optimization approach based on the nondominated sorting genetic algorithm (NSGA) is used to evaluate the Pareto front for minimum cost and volume designs. A sequential workflow of the different models embedded within a scripting environment developed in MATLAB™ is used for automating the entire process.

Dynamic Optimization of Steel Catenary Risers Based on Reliability Using Metamodel

2010 ◽  
Author(s):  
Wenqing Zheng ◽  
Hezhen Yang
Keyword(s):  
Dynamic Optimization ◽  
Computational Cost ◽  
Minimum Cost ◽  
Probabilistic Constraints ◽  
Optimization Approach ◽  
Element Analysis ◽  
Steel Catenary Riser ◽  
Reliability Based Design ◽  
Minimum Cost Design ◽  
Steel Catenary Risers

Reliability based design optimization (RBDO) of a steel catenary riser (SCR) using metamodel is investigated. The purpose of the optimization is to find the minimum-cost design subjecting to probabilistic constraints. To reduce the computational cost of the traditional double-loop RBDO, a single-loop RBDO approach is employed. The performance function is approximated by using metamodel to avoid time consuming finite element analysis during the dynamic optimization. The metamodel is constructed though design of experiments (DOE) sampling. In addition, the reliability assessment is carried out by Monte Carlo simulations. The result shows that the RBDO of SCR is a more rational optimization approach compared with traditional deterministic optimization, and using metamodel technique during the dynamic optimization process can significantly decrease the computational expense without sacrificing accuracy.

Shape Optimization of a Small Bus Steering Knuckle Considering a Fatigue Load

2013 ◽  
Vol 740 ◽  
pp. 319-322 ◽  
Author(s):  
Young Choon Lee ◽  
Nam Jin Jeon ◽  
Cheol Kim ◽  
Seo Yeon Ahn ◽  
Myung Jae Cho
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Shape Optimization ◽  
Minimum Weight ◽  
Cyclic Fatigue ◽  
Fatigue Load ◽  
Element Analysis ◽  
Gradient Based

Finite element analysis was accomplished for a steering knuckle component of a small bus to see whether the static and fatigue strength requirements were satisfied or not. The knuckle was modeled with ANSYS 10-node quadratic elements. The cyclic fatigue load was applied and Soderberg criteria were applied to check the fatigue life. The knuckle structure has an infinite life (10-6 cycle) judging from the fatigue analyses. Shape optimization based on the gradient based method has been performed in order to find out the knuckle shape that has a minimum weight and satisfies the static and fatigue strength requirements. As a result of shape optimization, the weight of the steering knuckle was reduced 8%.

A framework for tolerance design considering systematic and random uncertainties due to operating conditions

2019 ◽  
Vol 39 (5) ◽  
pp. 854-871
Author(s):  
S. Khodaygan
Keyword(s):  
Operating Conditions ◽  
Tolerance Allocation ◽  
Manufacturing Cost ◽  
Tolerance Design ◽  
Element Analysis ◽  
Content Type ◽  
Multi Objective ◽  
Mechanical Assemblies ◽  
Conflicting Objectives ◽  
Random Uncertainties

Purpose The purpose of this paper is to present a novel Kriging meta-model assisted method for multi-objective optimal tolerance design of the mechanical assemblies based on the operating conditions under both systematic and random uncertainties. Design/methodology/approach In the proposed method, the performance, the quality loss and the manufacturing cost issues are formulated as the main criteria in terms of systematic and random uncertainties. To investigate the mechanical assembly under the operating conditions, the behavior of the assembly can be simulated based on the finite element analysis (FEA). The objective functions in terms of uncertainties at the operating conditions can be modeled through the Kriging-based metamodeling based on the obtained results from the FEA simulations. Then, the optimal tolerance allocation procedure is formulated as a multi-objective optimization framework. For solving the multi conflicting objectives optimization problem, the multi-objective particle swarm optimization method is used. Then, a Shannon’s entropy-based TOPSIS is used for selection of the best tolerances from the optimal Pareto solutions. Findings The proposed method can be used for optimal tolerance design of mechanical assemblies in the operating conditions with including both random and systematic uncertainties. To reach an accurate model of the design function at the operating conditions, the Kriging meta-modeling is used. The efficiency of the proposed method by considering a case study is illustrated and the method is verified by comparison to a conventional tolerance allocation method. The obtained results show that using the proposed method can lead to the product with a more robust efficiency in the performance and a higher quality in comparing to the conventional results. Research limitations/implications The proposed method is limited to the dimensional tolerances of components with the normal distribution. Practical implications The proposed method is practically easy to be automated for computer-aided tolerance design in industrial applications. Originality/value In conventional approaches, regardless of systematic and random uncertainties due to operating conditions, tolerances are allocated based on the assembly conditions. As uncertainties can significantly affect the system’s performance at operating conditions, tolerance allocation without including these effects may be inefficient. This paper aims to fill this gap in the literature by considering both systematic and random uncertainties for multi-objective optimal tolerance design of mechanical assemblies under operating conditions.

Automated Decomposition of Complex Parts for Manufacturing With Advanced Joining Processes

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Brandon Massoni ◽  
Matthew I. Campbell
Keyword(s):  
Artificial Intelligence ◽  
Minimum Cost ◽  
Manufacturing Cost ◽  
Optimization Approach ◽  
Tree Search ◽  
Exploration And Exploitation ◽  
Design Engineers ◽  
Complex Part ◽  
Rotary Friction Welding ◽  
Complex Parts

Abstract Advanced joining processes can be used to build-up complex parts from stock shapes, thereby reducing waste material. For high-cost metals, this can significantly reduce the manufacturing cost. Nevertheless, determining how to divide a complex part into subparts requires experience and currently takes hours for an engineer to evaluate alternative options. To tackle this issue, we present an artificial intelligence (AI) tree search to automatically decompose parts for advanced joining and generate minimum cost manufacturing plans. The AI makes use of a multi-fidelity optimization approach to balance exploration and exploitation. This approach is shown to provide good manufacturing feedback in less than 30 minutes and produce results that are competitive against experienced design engineers. Although the manufacturing plan models presented were developed specifically for linear and rotary friction welding, the primary algorithms are applicable to other advanced joining operations as well.

Aerodynamic and Structural Design of a Centrifugal Fan for an Air Cushion Vehicle

2019 ◽  
Author(s):  
B. H. Cameron ◽  
E. W. Grald ◽  
T. M. Conboy ◽  
C. H. Passow ◽  
N. T. Kattamis ◽  
...  
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
Full Scale ◽  
Structural Performance ◽  
Centrifugal Impeller ◽  
Manufacturing Cost ◽  
Centrifugal Fan ◽  
Element Analysis ◽  
Air Cushion ◽  
Air Cushion Vehicle

Abstract A methodology is presented for the re-design of a large centrifugal impeller used for the lift fan on an air cushion vehicle. The design is driven by stringent requirements for aerodynamic and structural performance. It is also desired to minimize the fan’s life cycle cost, by reducing both the manufacturing cost and on-going maintenance burden. Improving the fan efficiency will increase the vehicle’s endurance and range, and minimizing life cycle cost will reduce the overall operational expenses. The lift fan assembly has a double-inlet impeller and an offset double-discharge volute. The new impeller design provides increased air flow with similar aerodynamic efficiency when compared to the prior design. To reduce the manufacturing cost, the new fan blade design can be produced by an aluminum extrusion process. The manufacturing process dictates that the blade cross-section be two-dimensional across the entire span, which poses structural challenges for attachment of the blades to the shroud and center disk. Analysis of the aerodynamic and structural performance of the lift fan was carried out using computational fluid dynamics (CFD) and structural finite element analysis (FEA) models. The fabrication of full-scale lift fan components is described. Plans for final assembly and for conducting full-scale, full-power aerodynamic testing will also be explained.

Fatigue Life Prediction of Fan Blade Using Nominal Stress Method and Cumulative Fatigue Damage Theory

2020 ◽  
Vol 37 (2) ◽  
pp. 135-139 ◽  
Author(s):  
Hong-Zhong Huang ◽  
Cheng-Geng Huang ◽  
Zhaochun Peng ◽  
Yan-Feng Li ◽  
Hengsu Yin
Keyword(s):  
Fatigue Life ◽  
Aircraft Engine ◽  
Nominal Stress ◽  
Load Spectrum ◽  
Element Analysis ◽  
Service Operation ◽  
Damage Theory ◽  
Fatigue Notch Factor ◽  
Fan Blade ◽  
Cumulative Fatigue Damage

AbstractFan blade is one of the key parts used in aircraft engine and its failure is mainly caused by fatigue fracture. This paper aims to predict fatigue life of fan blade during its service operation. First, the effective load and stress of fan blade are obtained by using finite element analysis and simulation. Second, the fatigue notch factor of fan blade is determined by using the nominal stress method. Then, the material properties of fan blade are used to correct and obtain the $S - N$ curve of fan blade. Finally, according to the actual load spectrum of three working loading cycles in 900h, the Miner’s damage accumulation rule is employed to predict the fatigue life of fan blade.

Design optimization of an automobile torque arm using global and successive surrogate modeling approaches

2018 ◽  
Vol 233 (6) ◽  
pp. 1453-1465 ◽  
Author(s):  
Erdem Acar ◽  
Nahide Tüten ◽  
Mehmet Ali Güler
Keyword(s):  
Fatigue Life ◽  
Design Optimization ◽  
Minimum Weight ◽  
Computational Cost ◽  
Surrogate Modeling ◽  
Optimization Approach ◽  
Finite Element Software ◽  
Initial Design ◽  
Modeling Approaches ◽  
Modeling Approach

The design of lightweight automotive structures has become a prevalent practice in the automotive industry. This study focuses on design optimization of an automobile torque arm subjected to cyclic loading. Starting from an available initial design, the shape of the torque arm is optimized for minimum weight such that the fatigue life of the torque arm does not fall below that of the initial design and the maximum von Mises stress developed in the torque arm does not exceed that of the initial design. The stresses are computed using ANSYS finite element software, and the fatigue life is calculated using the Smith–Watson–Topper model. Surrogate-based optimization approach is used to reduce the computational cost. Optimization results based on global surrogate modeling and successive surrogate modeling approaches are compared. It is found that the successive surrogate modeling approach results in 28.7% weight reduction for the torque arm, whereas the global surrogate modeling approach results in 25.7% weight saving for the torque arm.

scholarly journals A Cost Based Methodology for Design Optimization

2005 ◽  
Author(s):  
A. R. Rao ◽  
A. J. Keane ◽  
J. P. Scanlan
Keyword(s):  
Design Optimization ◽  
Cost Estimation ◽  
Decision Support Tool ◽  
Aircraft Engine ◽  
Optimization Techniques ◽  
Automated System ◽  
Manufacturing Cost ◽  
Element Analysis ◽  
Support Tool ◽  
Feature Based

Design optimization algorithms have traditionally focused on lowering weight and improving structural performance. Although cost is a vital factor in every emerging design, existing tools lack key features and capabilities in optimizing designs for minimum product cost at acceptable performance levels. This paper presents a novel methodology for developing a decision support tool for designers based on manufacturing cost. The approach focuses on exploiting the advantages offered by combining parametric CAD, Finite element analysis, feature based cost estimation and optimization techniques within a single automated system. This methodology is then applied in optimizing the geometry for minimum manufacturing cost of an engine mounting link from a Rolls-Royce civil aircraft engine.

A Simplified Design Model for Modular Steel Buildings Subject to Vapor Cloud Explosions (VCEs)

2020 ◽  
Vol 14 ◽  
Author(s):  
Osama Bedair
Keyword(s):  
Dynamic Response ◽  
Minimum Cost ◽  
Design Parameters ◽  
Front Wall ◽  
Steel Buildings ◽  
Element Analysis ◽  
Analysis And Design ◽  
Vapor Cloud ◽  
Building Components ◽  
Analytical Expressions

Background: Modular steel buildings (MSB) are extensively used in petrochemical plants and refineries. Limited guidelines are available in the industry for analysis and design of (MSB) subject to accidental vapor cloud explosions (VCEs). Objectives: The paper presents simplified engineering model for modular steel buildings (MSB) subject to accidental vapor cloud explosions (VCEs) that are extensively used in petrochemical plants and refineries. Method: A Single degree of freedom (SDOF) dynamic model is utilized to simulate the dynamic response of primary building components. Analytical expressions are then provided to compute the dynamic load factors (DLF) for critical building elements. Recommended foundation systems are also proposed to install the modular building with minimum cost. Results: Numerical results are presented to illustrate the dynamic response of (MSB) subject to blast loading. It is shown that (DLF)=1.6 is attained at (td/t)=0.4 for front wall (W1) with (td/T)=1.25. For side walls (DLF)=1.41 and is attained at (td/t)=0.6. Conclusions: The paper presented simplified tools for analysis and design of (MSB) subject accidental vapor cloud blast explosions (VCEs). The analytical expressions can be utilized by practitioners to compute the (MSB) response and identify the design parameters. They are simple to use compared to Finite Element Analysis.

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