Topology Optimization for Work Flat of Tower-Belt under Multi-Loading Cases

2012 ◽  
Vol 197 ◽  
pp. 614-618
Author(s):  
Yi Xian Du ◽  
Jin Run Hu ◽  
Zi Fan Fang ◽  
Qi Hua Tian
Keyword(s):  
Topology Optimization ◽  
Static Analysis ◽  
Geometric Model ◽  
Mathematical Optimization ◽  
Structural Models ◽  
Optimal Topology ◽  
Multiple Objective ◽  
Objective Functions ◽  
Minimum Compliance ◽  
Mathematical Optimization Model

Taking minimum compliance of the whole structure as the objective, the mathematical optimization model of multi-loading cases topology optimization is constructed by using the weight compromise programming method to coordinate the multiple objective functions. The optimal topology of the work flat is obtained using Hyperworks/Optistruct software and geometric model is reconstructed. The static analysis of original and reconstructed structural models of the work flat show that the optimized structure can not only decrease the weight, but also improve the stiffness and reduce the stress. The work flat will be more safe and reliable than before.

Volume Adjustable Topology Optimization with Multiple Displacement Constraints

2017 ◽  
Vol 34 (6) ◽  
pp. 759-770
Author(s):  
C. W. Huang ◽  
K. W. Chou
Keyword(s):  
Topology Optimization ◽  
Volume Ratio ◽  
Optimization Methods ◽  
Optimal Topology ◽  
Volume Constraint ◽  
Functional Constraints ◽  
Topology Optimization Problem ◽  
Finite Element Software ◽  
Minimum Compliance ◽  
Displacement Constraints

AbstractMost topology optimization methods seek optimal topologies that satisfy a minimum compliance with a pre-specified volume constraint in the design domain. However, practical designs often include various functional constraints and the optimal solid volume ratios are unknown a priori, which implies a gap between topology optimization methods and practical designs in industries. This paper studies the performance-based topology optimization (PTO) problem that searches for the optimal topology with minimum compliance to satisfy the pre-specified functional constraints without a pre-specified volume constraint. A novel element-based evolutionary switching method (ESM), which can automatically adjust solid volume ratio and material distribution, is developed and implemented using the commercial finite element software ABAQUS. The effects of displacement constraints on the optimal topologies are investigated, and the differences between PTO problems and the topology optimization problem which has a volume constraint are discussed. Numerical examples demonstrate that the optimal topologies are mainly determined by the load pattern and locally changed with respect to the location of the active displacement constraints. In addition, the displacement constraints to a large extent control the solid volume ratio of optimal topologies according to the allowable displacements in PTO problems. Finally, the proposed ESM could provide conservative solutions to the topology optimization with multiple displacement constraints problems.

scholarly journals A Method for Integration of Preferences to a Multi-Objective Evolutionary Algorithm Using Ordinal Multi-Criteria Classification

2021 ◽  
Vol 26 (2) ◽  
pp. 27
Author(s):  
Alejandro Castellanos-Alvarez ◽  
Laura Cruz-Reyes ◽  
Eduardo Fernandez ◽  
Nelson Rangel-Valdez ◽  
Claudia Gómez-Santillán ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Selective Pressure ◽  
Optimization Problems ◽  
Region Of Interest ◽  
Decision Makers ◽  
Multiple Objective ◽  
Objective Functions ◽  
Multi Objective ◽  
Imperfect Knowledge ◽  
Real World Problems

Most real-world problems require the optimization of multiple objective functions simultaneously, which can conflict with each other. The environment of these problems usually involves imprecise information derived from inaccurate measurements or the variability in decision-makers’ (DMs’) judgments and beliefs, which can lead to unsatisfactory solutions. The imperfect knowledge can be present either in objective functions, restrictions, or decision-maker’s preferences. These optimization problems have been solved using various techniques such as multi-objective evolutionary algorithms (MOEAs). This paper proposes a new MOEA called NSGA-III-P (non-nominated sorting genetic algorithm III with preferences). The main characteristic of NSGA-III-P is an ordinal multi-criteria classification method for preference integration to guide the algorithm to the region of interest given by the decision-maker’s preferences. Besides, the use of interval analysis allows the expression of preferences with imprecision. The experiments contrasted several versions of the proposed method with the original NSGA-III to analyze different selective pressure induced by the DM’s preferences. In these experiments, the algorithms solved three-objectives instances of the DTLZ problem. The obtained results showed a better approximation to the region of interest for a DM when its preferences are considered.

Development of Inner Rotating Core for a Molding Machine With Topology Optimization

2012 ◽  
Author(s):  
Hong Seok Park ◽  
Prakash Dahal
Keyword(s):  
Topology Optimization ◽  
Inner Core ◽  
Idea Generation ◽  
Optimal Topology ◽  
Polymer Concrete ◽  
Concept Design ◽  
Molding Machine ◽  
Optimization Study ◽  
Concept Evaluation ◽  
Main Component

Sulfur polymer concrete (SPC) is relatively new material used to replace Portland cement for making drain pipes currently being manufactured by horizontal spun technology which produces non-homogenous material distribution and low strength pipes. Due to drawbacks of existing machine, there is a necessity to design molding machine with improved technology for assuring homogenous compaction of material. In this research, a new machine is designed where inner rotating core is the main component for mixing, compressing and giving final shape of product. So, it is necessary to optimize this part in terms of topology to ensure robust functionality. First, the concept of a new molding machine was designed through problem exploration, idea generation, concept evaluation, and design improvement. The alternative was generated in consideration of customer requirements by applying TRIZ principles to overcome drawback of existing machine. One of the concepts was selected using scoring techniques where concepts are presented and compared with varieties of evaluating criteria. Topology optimization with density method has applied to design inner rotating core part for mass reduction and thereby optimum utilization of design space. Suitable engineering model was built based on loads, boundary condition and constraints. Loads are applied on inner core walls during mixing and compressing of sulfur concrete. Objective is focused to minimize the developed topology by maximizing stiffness. Repeated structural analysis is done to obtain the convergence data for optimal design. Optimized finite element topology is generated as CAD model for size optimization. The optimization study provided response charts of different design variables. Sensitivity analysis of the input variables helped in identifying the importance of each design variable and their respective effects on the output model. Different design points are rated on optimization study and best design points are chosen for the final dimension of structure. CATIA, OptiStruct and ANSYS are tools used for concept design, optimization of topology. To the end optimal topology is compared with the initial designed part in terms of weight and displacement. It is concluded that topology optimized model maximizes overall stiffness resulting in better and innovative product design with enhanced performance.

Thermo-Structural Coupled Topology Optimization of Micro-Capacitive Accelerometer

2012 ◽  
Vol 433-440 ◽  
pp. 3080-3085 ◽  
Author(s):  
Huan Yuan Chen ◽  
Yong Jun Xie ◽  
Dong Song Yan ◽  
Hao Liu ◽  
Jing Ming Li
Keyword(s):  
Topology Optimization ◽  
Elastic Beam ◽  
Optimal Topology ◽  
Beam Structure ◽  
Innovative Design ◽  
Maximum Deformation ◽  
Structure Topology ◽  
Capacitive Accelerometer ◽  
Limit Value ◽  
Moving Asymptotes

In order to enhance the working performance of micro-capacitive accelerometer in high temperature environment, the structure topology optimization of a micro-capacitive accelerometer is proposed. After the study of thermo-structural coupled governing equations and sensitivity analysis, the mass-block and elastic-beam structure of comb micro-capacitive accelerometer topology optimization model is established. Then the optimal topology forms of mass-block and elastic-beam structure are obtained with the MMA (method of moving asymptotes) method. At last, the calculating results indicate that the maximum deformation at acceleration detection direction is only 22nm at the operating temperature range of 0~300°C, which less than the maximum deformation of the limit value (25nm), and provides a reliable way for innovative design of micro-capacitive accelerometer.

scholarly journals A Mathematical Optimization Model for Locating Telecenters

2012 ◽  
Vol 03 (03) ◽  
pp. 251-263 ◽  
Author(s):  
Morteza Tabatabaie Shourijeh ◽  
Mohammad Kermanshah ◽  
Amir Reza Mamdoohi ◽  
Ardeshir Faghri ◽  
Khaled Hamad
Keyword(s):  
Optimization Model ◽  
Mathematical Optimization ◽  
Mathematical Optimization Model

scholarly journals Optimal Semi-Competitive Intermediation Networks

2020 ◽  
Vol 20 (5) ◽  
pp. 81-94
Author(s):  
Amelia Bădică ◽  
Costin Bădică ◽  
Maria Ganzha ◽  
Mirjana Ivanović ◽  
Marcin Paprzycki
Keyword(s):  
Optimization Model ◽  
Numerical Optimization ◽  
Autonomous Agents ◽  
Mathematical Optimization ◽  
Optimal Strategies ◽  
Directed Acyclic Graphs ◽  
Pricing Strategies ◽  
Computational Results ◽  
Acyclic Graphs ◽  
Mathematical Optimization Model

AbstractIn this work we address the problem of optimizing collective profitability in semi-competitive intermediation networks defined as augmented directed acyclic graphs. Network participants are modeled as autonomous agents endowed with private utility functions. We introduce a mathematical optimization model for defining pricing strategies of network participants. We employ welfare economics aiming to maximize the Nash social welfare of the intermediation network. The paper contains mathematical results that theoretically prove the existence of such optimal strategies. We also discuss computational results that we obtained using a nonlinear convex numerical optimization package.

Improvement of a topological level-set approach to find optimal topology by considering body forces

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Meisam Takalloozadeh ◽  
Gil Ho Yoon
Keyword(s):  
Topology Optimization ◽  
Level Set ◽  
Thermal Loading ◽  
Topological Derivative ◽  
Optimization Process ◽  
Optimal Topology ◽  
Content Type ◽  
Body Forces ◽  
Applied Forces ◽  
Level Set Approach

Purpose Body forces are always applied to structures in the form of the weight of materials. In some cases, they can be neglected in comparison with other applied forces. Nevertheless, there is a wide range of structures in civil and mechanical engineering in which weight or other types of body forces are the main portions of the applied loads. The optimal topology of these structures is investigated in this study. Design/methodology/approach Topology optimization plays an increasingly important role in structural design. In this study, the topological derivative under body forces is used in a level-set-based topology optimization method. Instability during the optimization process is addressed, and a heuristic solution is proposed to overcome the challenge. Moreover, body forces in combination with thermal loading are investigated in this study. Findings Body forces are design-dependent loads that usually add complexity to the optimization process. Some problems have already been addressed in density-based topology optimization methods. In the present study, the body forces in a topological level-set approach are investigated. This paper finds that the used topological derivative is a flat field that causes some instabilities in the optimization process. The main novelty of this study is a technique used to overcome this challenge by using a weighted combination. Originality/value There is a lack of studies on level-set approaches that account for design-dependent body forces and the proposed method helps to understand the challenges posed in such methods. A powerful level-set-based approach is used for this purpose. Several examples are provided to illustrate the efficiency of this method. Moreover, the results show the effect of body forces and thermal loading on the optimal layout of the structures.

Abstract 108: Optimal In-Hospital Defibrillator Placement

Circulation ◽  
2019 ◽  
Vol 140 (Suppl_2) ◽  
Author(s):  
Kwan Hon Benjamin Leung ◽  
Matthew Yang ◽  
Christopher Sun ◽  
Katherine S Allan ◽  
Natalie Wong ◽  
...  
Keyword(s):  
Average Distance ◽  
Mathematical Optimization ◽  
Rank Test ◽  
Relative Decrease ◽  
Signed Rank ◽  
Out Of Sample ◽  
Signed Rank Test ◽  
Academic Teaching Hospital ◽  
Mathematical Optimization Model ◽  
The Difference

Introduction: Delays in defibrillation of in-hospital cardiac arrests (IHCAs) can reduce the likelihood of survival. Mathematical optimization has been shown to improve public location defibrillator placement but has not been applied to in-hospital defibrillator placement. Objective: To determine if mathematical optimization of in-hospital defibrillator placements can reduce distances to IHCAs compared to current placements in a large academic teaching hospital. Methods: We identified all treated IHCAs and defibrillator placements in St. Michael’s Hospital in Toronto, Canada from Jan. 2007 to Jun. 2017 and mapped them to a 3-D representation of the hospital that we developed from blueprints. An equal number of optimal defibrillator locations was identified using a mathematical optimization model that minimizes the average distance between IHCAs and the closest defibrillator in a 10-fold cross-validation approach. The optimized and current defibrillator locations were compared in terms of average distance to the out-of-sample IHCAs in each fold. We repeated the analysis excluding IHCAs and defibrillators in intensive care units (ICUs), operating theaters (OTs), and the emergency department (ED). Significance in the difference of average distance was determined using a Wilcoxon signed-rank test. Results: We identified 537 treated IHCAs and 53 defibrillators within the hospital during the study period. Of these, 236 IHCAs and 38 defibrillators were outside of ICUs, OTs, and the ED. Optimal defibrillator placements reduced the average defibrillator-to-IHCA distance from 17.1 m to 3.8 m, a relative decrease of 77.8% (P<0.01) on all IHCAs compared to current defibrillator placements. For non-ICU/OT/ED IHCAs, the average distance was reduced from 18.3 m to 9.8 m, a relative decrease of 46.4% (P<0.01). Conclusion: Optimization-guided placement of in-hospital defibrillators can significantly reduce the distance from an IHCA to the closest defibrillator.

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