Study of Parametric and Non-Parametric Optimization of a Rotor-Bearing System

2014 ◽  
Author(s):  
Youngwon Hahn ◽  
John I. Cofer
Keyword(s):  
Topology Optimization ◽  
Critical Speed ◽  
Parametric Optimization ◽  
Optimization Methods ◽  
Optimization Process ◽  
Support Structure ◽  
And Topology ◽  
Design Variables ◽  
Rotor Bearing ◽  
Non Parametric

The optimization techniques most widely used in various industrial fields for structural optimization generally can be placed into two categories: parametric optimization and non-parametric optimization. In parametric optimization, the parametric variables defining a geometric model are used as design variables. For example, all dimensions defining a structural shape in a CAD (Computer-Aided Design) system can be used as parameters in an optimization process to achieve a desired objective. In non-parametric optimization, an initial outer boundary of the geometry is defined and the optimization process either removes mass without changing the node locations in the calculation mesh (topology optimization) or directly manipulates the node locations (shape optimization) to achieve a desired objective. Nowadays, the combination of both parametric and non-parametric optimization methods can provide an attractive approach to satisfy the requirements of advanced levels of structural performance. While optimization methods have been widely used in many turbomachinery applications, such as turbine and compressor blading, combustors, and casings, in the rotordynamics field, relatively little work has been done to investigate methods for the overall optimization of rotor-bearing-support structures to achieve desired system behavior. In this paper, a combined parametric and non-parametric optimization method is applied to a rotor-bearing-support structure in order to achieve the desired critical speed and unbalance response. The bearing design variables are selected as parametric design variables and topology optimization is applied to the support structure. The entire optimization workflow is constructed in the commercial software Isight, and Abaqus and ATOM (Abaqus Topology Optimization Module) are used for rotordynamics analysis and topology optimization. The desired critical speed and unbalance response can be obtained with the optimized topology of the support structure.

Simultaneous Shape and Topology Optimization of Planar Linkage Mechanisms Based on the Spring-Connected Rigid Block Model

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Jeonghan Yu ◽  
Sang Min Han ◽  
Yoon Young Kim
Keyword(s):  
Topology Optimization ◽  
Simultaneous Optimization ◽  
Optimization Process ◽  
Rigid Block ◽  
Low Resolution ◽  
Block Model ◽  
Shape And Topology Optimization ◽  
Fixed Grid ◽  
Computation Efficiency ◽  
And Topology

Abstract Using the topology optimization can be an effective means of synthesizing planar rigid-body linkage mechanisms to generate desired motion, as it does not require a baseline mechanism for a specific topology. While most earlier studies were mainly concerned with the formulation and implementation of topology optimization-based synthesis in a fixed grid, this study aims to realize the simultaneous shape and topology optimization of planar linkage mechanisms using a low-resolution spring-connected rigid block model. Here, we demonstrate the effectiveness of simultaneous optimization over a higher-resolution fixed-grid rigid block-based topology optimization process. When shape optimization to change the block shapes is combined with topology optimization to synthesize the mechanism, the use of low-resolution discretized models improves the computation efficiency considerably and helps to yield compact mechanisms with less complexity, making them more amenable to fabrication. After verifying the effectiveness of the simultaneous shape and topology optimization process with several benchmark problems, we apply the method to synthesize a mechanism which guides a planar version of a human's gait trajectory.

scholarly journals Size and Topology Optimization for Trusses with Discrete Design Variables by Improved Firefly Algorithm

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Yue Wu ◽  
Qingpeng Li ◽  
Qingjie Hu ◽  
Andrew Borgart
Keyword(s):  
Topology Optimization ◽  
Firefly Algorithm ◽  
Optimization Problems ◽  
Optimization Method ◽  
Structural Topology ◽  
Discrete Variables ◽  
And Topology ◽  
Design Variables ◽  
Improved Firefly Algorithm ◽  
Discrete Design Variables

Firefly Algorithm (FA, for short) is inspired by the social behavior of fireflies and their phenomenon of bioluminescent communication. Based on the fundamentals of FA, two improved strategies are proposed to conduct size and topology optimization for trusses with discrete design variables. Firstly, development of structural topology optimization method and the basic principle of standard FA are introduced in detail. Then, in order to apply the algorithm to optimization problems with discrete variables, the initial positions of fireflies and the position updating formula are discretized. By embedding the random-weight and enhancing the attractiveness, the performance of this algorithm is improved, and thus an Improved Firefly Algorithm (IFA, for short) is proposed. Furthermore, using size variables which are capable of including topology variables and size and topology optimization for trusses with discrete variables is formulated based on the Ground Structure Approach. The essential techniques of variable elastic modulus technology and geometric construction analysis are applied in the structural analysis process. Subsequently, an optimization method for the size and topological design of trusses based on the IFA is introduced. Finally, two numerical examples are shown to verify the feasibility and efficiency of the proposed method by comparing with different deterministic methods.

Structural Topology Design Considering Reliability

2005 ◽  
Vol 297-300 ◽  
pp. 1901-1906 ◽  
Author(s):  
Seung Jae Min ◽  
Seung Hyun Bang
Keyword(s):  
Topology Optimization ◽  
Design Optimization ◽  
Optimization Problem ◽  
Performance Measure ◽  
Topology Design ◽  
Optimization Process ◽  
Programming Algorithm ◽  
Probabilistic Design ◽  
Most Probable Point ◽  
Design Variables

In the design optimization process design variables are selected in the deterministic way though those have uncertainties in nature. To consider variances in design variables reliability-based design optimization problem is formulated by introducing the probability distribution function. The concept of reliability has been applied to the topology optimization based on a reliability index approach or a performance measure approach. Since these approaches, called double-loop singlevariable approach, requires the nested optimization problem to obtain the most probable point in the probabilistic design domain, the time for the entire process makes the practical use infeasible. In this work, new reliability-based topology optimization method is proposed by utilizing single-loop singlevariable approach, which approximates searching the most probable point analytically, to reduce the time cost and dealing with several constraints to handle practical design requirements. The density method in topology optimization including SLP (Sequential Linear Programming) algorithm is implemented with object-oriented programming. To examine uncertainties in the topology design of a structure, the modulus of elasticity of the material and applied loadings are considered as probabilistic design variables. The results of a design example show that the proposed method provides efficiency curtailing the time for the optimization process and accuracy satisfying the specified reliability.

Design of the structural arrangement for a space reflector via parametric and topology optimization

2019 ◽  
Vol 20 (4) ◽  
pp. 276-284
Author(s):  
Elena K. Filina ◽  
Evgenii S. Golubev ◽  
Konstantin V. Mikhailovskiy ◽  
Mikhail Yu. Arkhipov
Keyword(s):  
Topology Optimization ◽  
Optimization Problem ◽  
Parametric Optimization ◽  
Areal Density ◽  
Temperature Gradients ◽  
Structural Arrangement ◽  
Geometry Design ◽  
And Topology ◽  
Space Antennas ◽  
Surface Figure

Development of the optimal structural arrangement for a reflector with the aim to improve its mass and design is of importance due to the necessity to increase areal density and decrease rigidity of the modern space antennas vehicles. Currently, CAE-systems allow to design reflectors using both traditional methods, for example, parametric optimization, and methods which are innovative in this field, such as topology optimization. The paper compares two methods of the structural arrangement design for a thin dimensionally stable reflector operating as part of a geostationary spacecraft: parametric and topology optimization. The algorithms of the structural arrangement development which include the statement of the optimization problem, geometry design and a number of check analyses are presented. A number of structural of a space reflector design under the action of loads at the stage of launch, temperature gradients at the exploitation conditions and modal analysis is performed. The designed reflectors are compared. The studies performed allowed us to develop the optimal structural arrangement for a space reflector using the parametric and topology optimization. The optimal structural arrangement for a space reflector using the optimization could be produced surface figure error (estimated in RMS) with respect to the theoretical paraboloid.

Optimal Design of Rotor-Bearing Systems Using Immune-Genetic Algorithm

2001 ◽  
Vol 123 (3) ◽  
pp. 398-401 ◽  
Author(s):  
Byeong-Keun Choi ◽  
Bo-Suk Yang
Keyword(s):  
Genetic Algorithm ◽  
Critical Speed ◽  
Q Factor ◽  
Immune Genetic Algorithm ◽  
Dynamic Constraints ◽  
Design Variables ◽  
Resonance Response ◽  
Rotor Bearing ◽  
Combined Algorithm ◽  
Bearing System

In this paper, the new combined algorithm (Immune-Genetic Algorithm, IGA) is applied to minimize the total weight of the shaft and the resonance response (Q factor), and to yield the critical speeds as far from the operating speed as possible. These factors play very important roles in designing a rotor-bearing system under the dynamic behavior constraints. The shaft diameter, the bearing length and clearance are chosen as the design variables. The results show that the IGA can reduce the weight of the shaft and improve the critical speed and Q factor with dynamic constraints.

scholarly journals Non-Parametric Shape Optimization of a Football Boot Bottom Plate

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 152
Author(s):  
Jeong-Ro Lee ◽  
Andy Harland ◽  
Jonathan Roberts
Keyword(s):  
Shape Optimization ◽  
Parametric Optimization ◽  
Structure Sensitivity ◽  
Optimization Process ◽  
Optimum Shape ◽  
Bottom Plate ◽  
Future Research ◽  
Key Features ◽  
Non Parametric

This paper describes the non-parametric shape optimization process for a football boot bottom plate. The non-parametric shape optimization process changes the nodes’ location of a model and outputs an optimum shape, which satisfies an optimization objective. The methodology presented in this study was able to change the shape of the football boot bottom plate, especially the dimensions of key features, to achieve four different target bending stiffnesses. Tosca Structure sensitivity-based shape optimization was used to perform the optimization process and output optimum bottom plates. Future research is needed to investigate the accuracy of the process in comparison with that of the previously developed parametric optimization process.

Structure Analysis and Topology Optimization of a Bent-Bar-Frame Piston Based on the Variable Density Approach

2014 ◽  
Author(s):  
Jie Zhao ◽  
Farong Du ◽  
Wei Yao
Keyword(s):  
Topology Optimization ◽  
Thermal Loading ◽  
Coupled Model ◽  
Variable Density ◽  
Structural Topology ◽  
Connecting Rod ◽  
And Topology ◽  
Design Variables ◽  
Cylinder Piston ◽  
Optimized Model

The iterative algorithm of design variables for structural topology optimization is derived by using variable density approach and Finite Element Method. A coupled model of bent-bar-frame piston is built considering the contact between piston and cylinder, piston and piston pin, piston pin and connecting rod. Based on this model, the deformation and stress of piston are analyzed under each of mechanical or thermal loading. Taking structural weight as the objective function of optimization, three desired regions of piston are optimized by using variable density approach in commercial FEA software HYPERMESH and ANSYS. Finally, the deformation and temperature of the optimized model are compared with prototype by using the same loading and boundary conditions. The results show that the weight of piston is reduced by 12.5% while meeting the required specifications.

scholarly journals Topology and Parametric Optimization-Based Design Processes for Lightweight Structures

2020 ◽  
Vol 10 (13) ◽  
pp. 4496
Author(s):  
Evangelos Tyflopoulos ◽  
Martin Steinert
Keyword(s):  
Topology Optimization ◽  
Optimization Design ◽  
Parametric Optimization ◽  
Optimization Procedure ◽  
Optimization Approach ◽  
Design Processes ◽  
Initial Strength ◽  
Lightweight Structures ◽  
Material Optimization ◽  
And Topology

Topology and Parametric Optimization are two of the most implemented material optimization approaches. However, it is not clear in the literature which optimization procedure, or possible combination of them, can lead to the best results based on material reduction and optimization time. In this paper, a quantitative comparison of different topology and parametric optimization design processes is conducted using three benchmark examples: A Hollow Plate, an L-Bracket, and a Messerschmitt–Bölkow–Blohm Beam (MBB-Beam). Ten different design processes that were developed in each case study resulted in 30 simulations in total. The design processes were clustered in three main design workflows: The Topology Optimization, the Parametric Optimization, and the Simultaneous Parametric and Topology Optimization. Their results were compared with respect to mass, stress, and time. The Simultaneous Parametric and Topology Optimization approach gave the lightest design solutions without compromising their initial strength but also increased the optimization time. The findings of this paper will help the designers in the pursuit of lightweight structures and will create the basis for the identification of the ideal material optimization procedure.

Optimal Design of CNC Crushing Machine Steady Based on Genetic Algorithm

2013 ◽  
Vol 397-400 ◽  
pp. 1129-1132
Author(s):  
De Xin Zhang ◽  
Ming Jian Han ◽  
Yang Jie Ou ◽  
Guo Qing Wang ◽  
Guo Qing Hao ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Genetic Algorithms ◽  
Topology Optimization ◽  
Optimization Design ◽  
Structure Optimization ◽  
Multi Objective Optimization ◽  
Shape And Topology Optimization ◽  
And Topology ◽  
Design Variables ◽  
Starting Point

The Genetic Algorithms In engineering structure optimization design includes Truss Structure optimization, Shape and topology optimization, Composite materials optimization, layout optimization, Multi-Objective Optimization. This paper combined with engineering background , Selecting the Pressing gear of CNC crushing Machine Steady as starting point for Optimization modeling .Analyzing the simple conditions theoretical physical model of CNC Crushing Machine Steady, Reasonably selected design variables ,using Conventional Methods and genetic algorithms to optimize the Steady ,obtainning every iterative step relevant data under the two methods, and analyzing the results ,analysis the accuracy of the optimize results through the stress and displacement map .

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