scholarly journals Structurally Constrained Aerodynamic Adjoint Optimisation of Highly Loaded Compressor Blades

2021 ◽  
Author(s):  
Cleopatra Cuciumita ◽  
Alistair John ◽  
Ning Qin ◽  
Shahrokh Shahpar
Keyword(s):  
Objective Function ◽  
Response Surface ◽  
Von Mises Stress ◽  
Free Form ◽  
Design Parameters ◽  
Stress Constraint ◽  
Efficiency Gain ◽  
Computational Costs ◽  
Von Mises ◽  
Highly Loaded

Abstract Adjoint aerodynamic optimisation has recently gained increased popularity for turbomachinery applications due to the large number of parameters that can be used without incurring additional major computational costs. This work presents an adjoint based aero-structural optimisation method having efficiency as the objective function and maximum von Mises stress set as a constraint. The full optimisation loop was set up with free-form deformation for geometry parametrisation. A response surface was created beforehand for computing the maximum von Mises stress using a meshless method. A discrete adjoint approach was used to obtain the gradients of the objective function with respect to each design parameter, while the constraint gradients were computed using finite differences. A sequential least squares programming algorithm was used as the optimizer. Tests carried out on a highly loaded compressor blade showed that the method successfully increases the efficiency by more than 3% while maintaining the maximum stress under the imposed value. The results also showed that the constrained optimisation loses about 1% in potential efficiency gain compared to the same optimisation process without stress constraint. Overall, the work provides a methodology for conducting structurally constrained adjoint aerodynamic optimisation that can be applied for large number of design parameters while maintaining low computational costs. It also provides reference for constructing and selecting a response surface to be used in the optimisation process.

scholarly journals OPTIMASI DESAIN STENT PLA MENGGUNAKAN METODE RESPONSE SURFACE (RSM) UNTUK MEMPEROLAH FLEKSIBILITAS TERBAIK

2019 ◽  
Vol 8 (1) ◽  
pp. 48
Author(s):  
Sukiman B
Keyword(s):  
Blood Vessel ◽  
Response Surface ◽  
Optimization Design ◽  
Bending Moment ◽  
Von Mises Stress ◽  
Design Parameters ◽  
Angular Change ◽  
Minimum Stress ◽  
Von Mises ◽  
Safety Limit

The stent installation is one of cardiovascular disease treatments which is selected the most to handle patients with blood vessel disease. As the demand for stents increases, more researches are aimed at developing them. This study aims to obtain the optimal link design to produce the best flexibility to the change of stent angle with minimum stress so as not to injure blood vessel plaque. In this study, the stents are polymer stent with different types of links made with PLA materials with strut mirror (S><) design. The study was conducted on two stent configurations, namely crimped and expanded to determine the ability of angular change and maximum stress experienced by both when bending moment applied. The bending moment test was done through simulation based on finite element method in software Abaqus 6.14. The simulation results were then used as a model-making reference to determine the desired optimization design using the help of Minitab 18 software based on the response surface method. The results of this study indicate that the best optimal flexibility on crimped stent L1 to L5, which is the highest flexibility with von mises stress in the safety limit can be obtained based on a combination of link design parameters in the form of bending moment of 0.0074 N.mm with a thickness of 100 μm L3, and 0,0087 N.mm with a thickness of 106 μm L5. While at the expanded stent L1 to L5, the optimal link design parameter value for obtaining the best flexibility with von mises stress within the safety limit is a bending moment of 0.0075 N.mm with a thickness of 63.78 μm L3, 0.0067 N.mm with a thickness of 70 μm L5.

Design improvement and fatigue analysis for a bicycle handlebar stem system using uniform design method and genetic algorithm

2020 ◽  
Vol 234 (11) ◽  
pp. 2266-2278
Author(s):  
Cho-Pei Jiang ◽  
Ching-Wei Wu ◽  
Yung-Chang Cheng
Keyword(s):  
Genetic Algorithm ◽  
Objective Function ◽  
Safety Factor ◽  
Uniform Design ◽  
Optimization Procedure ◽  
Bending Test ◽  
Von Mises Stress ◽  
Kriging Interpolation ◽  
Optimized Design ◽  
Von Mises

An integrating optimization procedure is presented to improve the von Mises stress and fatigue safety factor for a handlebar stem system in a bicycle system. The optimization procedure involves uniform design of experiment, Kriging interpolation, genetic algorithm, and nonlinear programming method. Using ANSYS/Workbench software and the ISO 4210 bicycle handlebar stem testing standard, the von Mises stress for the lateral bending test simulation and the fatigue safety factor for the fatigue test simulation is calculated. The von Mises stress and fatigue safety factor are combined into a single and integrated objective function, and Kriging interpolation is then used to create the surrogate model of the integrated objective function. When the integrating optimization procedure is used, the integrated objective function demonstrates that the von Mises stress for the optimized handlebar stem is reduced to 225 MPa and the fatigue safety factor increases to 1.796. This shows that the optimized design increases the strength of the handlebar stem. The proposed technique yields a handlebar stem with an optimized shape.

scholarly journals Buckling Sensitivity of Ultra Fine Grained Material AA2618 Connecting Rod

2020 ◽  
Vol 8 (6) ◽  
pp. 4288-4294
Keyword(s):  
Primary Objective ◽  
Von Mises Stress ◽  
Design Parameters ◽  
Connecting Rod ◽  
Fine Grained ◽  
Buckling Stress ◽  
Ultrafine Grained ◽  
Fine Grained Material ◽  
Solid Works ◽  
Von Mises

The objective of the work is to evaluate the best design parameters of connecting rod using Ultrafine Grained Material AA2618. The critical buckling stress for existing material (C70S6) is high and the primary objective is to optimize connecting rod in terms of reduction of weight and stress. The numerical investigation has been carried out using ANSYS. Modeling of connecting rod is done in Solid works designing software. The analysis is performed on Ansys to calculate the critical buckling stress and Von-mises stress is calculated in the stress analysis by applying the maximum external load. The analysis results are plotted graphically and results are compared to find the useful outcomes which are used to predict the structural behavior of connecting rod under given load.

scholarly journals Parameterisation and Optimisation of a Hand-Rake Sweeper: Application in Olive Picking

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 379
Author(s):  
Rafael E. Hidalgo Fernández ◽  
Pilar Carranza-Cañadas ◽  
Francisco J. García-Salcedo ◽  
Paula Triviño-Tarradas
Keyword(s):  
Parametric Design ◽  
Low Cost ◽  
Von Mises Stress ◽  
Design Parameters ◽  
Olive Grove ◽  
Agricultural Activities ◽  
Design Software ◽  
Von Mises ◽  
Light Material

Olive picking is one of the most common social agricultural activities in many regions of Andalusia where the predominant crop is the traditional olive grove. The machinery used includes shakers, blowers and essential, low-cost hand-rake sweepers. The latter are generally used by the women of the squads to sweep the olives that fall from the trees. This article is focused on the design and optimisation of a hand-rake sweeper, in terms of durability and cost, for the picking of olives and other fruits, such as almonds, which are currently the main alternative to nonperennial crops in Andalusia. A parametric design of a hand-rake sweeper was created for this application using the design software CATIA, and its most vulnerable points were analysed in terms of effectiveness with varying design parameters, conducting usage simulations with ANSYS for a light material such as polypropylene. The maximum von Mises stress of the whole structure was 155.81 MPa. Using ANSYS, the dimension parameters of the hand-rake sweeper structure were optimised. The modified design was analysed again, showing a reduction of maximum tensions of 10.06%, as well as a decrease in its maximum elongations (0.0181 mm).

Topology optimization of structures subject to self-weight loading under stress constraints

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Renatha Batista dos Santos ◽  
Cinthia Gomes Lopes
Keyword(s):  
Topology Optimization ◽  
Stress Constraints ◽  
Topological Derivative ◽  
The Self ◽  
Von Mises Stress ◽  
Stress Constraint ◽  
Content Type ◽  
Derivative Method ◽  
Von Mises ◽  
Weight Loading

PurposeThe purpose of this paper is to present an approach for structural weight minimization under von Mises stress constraints and self-weight loading based on the topological derivative method. Although self-weight loading topology has been the subject of intense research, mainly compliance minimization has been addressed.Design/methodology/approachThe resulting minimization problem is solved with the help of the topological derivative method, which allows the development of efficient and robust topology optimization algorithms. Then, the derived result is used together with a level-set domain representation method to devise a topology design algorithm.FindingsNumerical examples are presented, showing the effectiveness of the proposed approach in solving a structural topology optimization problem under self-weight loading and stress constraint. When the self-weight loading is dominant, the presence of the regularizing term in the formulation is crucial for the design process.Originality/valueThe novelty of this research work lies in the use of a regularized formulation to deal with the presence of the self-weight loading combined with a penalization function to treat the von Mises stress constraint.

Simulation-Based Design of a Self-Folding Smart Material System

2013 ◽  
Author(s):  
Edwin Peraza-Hernandez ◽  
Darren Hartl ◽  
Richard Malak
Keyword(s):  
Three Dimensional ◽  
Building Blocks ◽  
Passive Layer ◽  
Heating Power ◽  
Von Mises Stress ◽  
Maximum Temperature ◽  
Design Parameters ◽  
Material System ◽  
Design Variables ◽  
Von Mises

Origami engineering — the practice of creating useful three-dimensional structures through folding operations on two-dimensional building-blocks — is receiving increased attention from the science, mathematics, and engineering communities. The topic of this paper is a new concept for a self-folding material system. It consists of an active, self-morphing laminate that includes two meshes of thermally-actuated shape memory alloy (SMA) separated by a compliant passive layer. The goal of this paper is to analyze several of the key engineering tradeoffs associated with the proposed self-folding material system. In particular, we examine how key design variables affect folding behavior in an SMA mesh-based folding sheet. The design parameters we consider in this study are wire thickness, mesh wire spacing, thickness of the insulating elastomer layer, and heating power. The output parameters are maximum von Mises stress in the SMA, maximum temperature in the SMA, and minimum folding angle. The results show that maximum temperature in the SMA is mostly dependent on the total heating power per unit width of SMA. The results also indicate that through-heating — heat transfer from one SMA layer to the other through the insulating elastomer — can impede folding for some physical configurations. However, we also find that one can mitigate this effect using a staggered mesh configuration in which the SMA wires on different layers are not aligned. Based on our results, we conclude that the new staggered mesh design can be effective in preventing unintended transformation of the non-actuated layer.

scholarly journals Computerized Generation and Finite Element Stress Analysis of Endodontic Rotary Files

2021 ◽  
Vol 11 (10) ◽  
pp. 4329
Author(s):  
Victor Roda-Casanova ◽  
Álvaro Zubizarreta-Macho ◽  
Francisco Sanchez-Marin ◽  
Óscar Alonso Ezpeleta ◽  
Alberto Albaladejo Martínez ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Computer Aided Design ◽  
Element Model ◽  
Transverse Load ◽  
Von Mises Stress ◽  
Design Parameters ◽  
Element Analysis ◽  
Design Skills ◽  
Von Mises

Introduction: The finite element method has been extensively used to analyze the mechanical behavior of endodontic rotary files under bending and torsional conditions. This methodology requires elevated computer-aided design skills to reproduce the geometry of the endodontic file, and also mathematical knowledge to perform the finite element analysis. In this study, an automated procedure is proposed for the computerized generation and finite element analysis of endodontic rotary files under bending and torsional conditions. Methods: An endodontic rotary file with a 25mm total length, 0.25mm at the tip, 1.20mm at 16mm from the tip, 2mm pitch and squared cross section was generated using the proposed procedure and submitted for analysis under bending and torsional conditions by clamping the last 3mm of the endodontic rotary file and applying a transverse load of 0.1N and a torsional moment of 0.3N·cm. Results: The results of the finite element analyses showed a maximum von Mises stress of 398MPa resulting from the bending analysis and a maximum von Mises stress of 843MPa resulting from the torsional analysis, both of which are next to the encastre point. Conclusions: The automated procedure allows an accurate description of the geometry of the endodontic file to be obtained based on its design parameters as well as a finite element model of the endodontic file from the previously generated geometry.

scholarly journals Parameterisation and Optimisation of a Hand-Rake Sweeper: Application in Olive Picking

2020 ◽  
Author(s):  
Rafael E. Hidalgo-Fernández ◽  
Pilar Carranza-Cañadas ◽  
Francisco J. García-Salcedo ◽  
Paula Triviño-Tarradas
Keyword(s):  
Parametric Design ◽  
Low Cost ◽  
Von Mises Stress ◽  
Design Parameters ◽  
Olive Grove ◽  
Agricultural Activities ◽  
Perennial Crops ◽  
Design Software ◽  
Von Mises ◽  
Light Material

Olive picking is one of the most common social agricultural activities in many regions of Andalusia where the predominant crop is the traditional olive grove. The machinery used includes shakers, blowers and an essential low-cost type: hand-rake sweepers. The latter are generally used by the women of the squads to sweep the olives that fall from the trees. This article is focused on the design and optimisation of a hand-rake sweeper, in terms of durability and cost, for the picking of olives and other fruits, such as almonds, which are currently the main alternative to non-perennial crops in Andalusia. A parametric design of a hand-rake sweeper was created for this application using the design software CATIA, and its most vulnerable points were analysed in terms of effectiveness with varying design parameters, conducting usage simulations with ANSYS for a light material such as polypropylene. The maximum von Mises stress of the whole structure was 155.81 MPa. Using ANSYS, the dimension parameters of the hand-rake sweeper structure were optimised. The modified design was analysed again, showing a reduction of maximum tensions of 10.06%, as well as a decrease in its maximum elongations (0.0181 mm).

Simulation-based search for optimal designs of accelerated life tests through response surface methodology

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Daniel Ayasse ◽  
Kangwon Seo
Keyword(s):  
Response Surface Methodology ◽  
Optimal Design ◽  
Objective Function ◽  
Response Surface ◽  
Failure Time ◽  
Simulated Data ◽  
Accelerated Life Test ◽  
Design Parameters ◽  
Content Type ◽  
Accelerated Life

PurposePlanning an accelerated life test (ALT) for a product is an important task for reliability practitioners. Traditional methods to create an optimal design of an ALT are often computationally burdensome and numerically difficult. In this paper, the authors introduce a practical method to find an optimal design of experiments for ALTs by using simulation and empirical model building.Design/methodology/approachInstead of developing the Fisher information matrix-based objective function and analytic optimization, the authors suggest “experiments for experiments” approach to create optimal planning. The authors generate simulated data to evaluate the quantity of interest, e.g. 10th percentile of failure time and apply the response surface methodology (RSM) to find an optimal solution with respect to the design parameters, e.g. test conditions and test unit allocations. The authors illustrate their approach applied to the thermal ALT with right censoring and lognormal failure time distribution.FindingsThe design found by the proposed approach shows substantially improved statistical performance in terms of the standard error of estimates of 10th percentile of failure time. In addition, the approach provides useful insights about the sensitivity of each decision variable to the objective function.Research limitations/implicationsMore comprehensive experiments might be needed to test its scalability of the method.Practical implicationsThis method is practically useful to find a reasonably efficient optimal ALT design. It can be applied to any quantities of interest and objective functions as long as those quantities can be computed from a set of simulated datasets.Originality/valueThis is a novel approach to create an optimal ALT design by using RSM and simulated data.

Bending Die Design for a Pre-Formed Sheet Metal with a Golden Finger Feature

2008 ◽  
Vol 594 ◽  
pp. 51-56
Author(s):  
Jinn Jong Sheu ◽  
Sheng Hao Fang
Keyword(s):  
Shear Stress ◽  
Material Flow ◽  
Quality Index ◽  
Design Method ◽  
Maximum Shear Stress ◽  
Die Design ◽  
Von Mises Stress ◽  
Design Parameters ◽  
Profile Design ◽  
Von Mises

In this paper, authors proposed an effective quality index of bending operation and a new punch profile design method to prevent defects. The proposed quality index is presented in terms of distance of fracture location with respect to the topmost plane of blank, the maximum von Mises stress, and the maximum shear stress. The Taguchi method with L18 orthogonal array was adopted to evaluate the effects of design parameters and find out the optimum design of punch profile. A new punch feature called “golden finger” was proposed to control the material flow and move the fracture defects out of the trimming line. The results of this study had demonstrated the optimum die design can be achieved with the proposed golden finger feature to obtain a sound product.

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