Experimental verification of textured mechanical seal designed using multi-objective optimization

2019 ◽  
Vol 71 (6) ◽  
pp. 766-771 ◽  
Author(s):  
Xiuying Wang ◽  
Michael Khonsari ◽  
Siyuan Li ◽  
Qingwen Dai ◽  
Xiaolei Wang
Keyword(s):  
Leakage Rate ◽  
Free Form ◽  
Optimization Approach ◽  
Multi Objective Optimization ◽  
Mechanical Seals ◽  
Content Type ◽  
Multi Objective ◽  
Load Carrying ◽  
And Control ◽  
Good Agreement

Purpose This study aims to simultaneously enhance the load-carrying capacity and control the leakage rate of mechanical seals by optimizing the texture shape. Design/methodology/approach A multi-objective optimization approach is implemented to determine the optimal “free-form” textures and optimal circular dimples. Experiments are conducted to validate the simulation results. Findings The experimental coefficient of friction (COF) and leakage rate are in good agreement with the calculated results. In addition, the optimal “free-form” texture shows a lower COF and a lower leakage in most cases. Originality/value This work provides a method to optimize the surface texture for a better combination performance of mechanical seals.

A Multi-Objective Optimization Approach on Spiral Grooves for Gas Mechanical Seals

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Xiuying Wang ◽  
Liping Shi ◽  
Wei Huang ◽  
Xiaolei Wang
Keyword(s):  
Optimization Approach ◽  
Multi Objective Optimization ◽  
Mechanical Seals ◽  
Independent Variables ◽  
Multi Objective ◽  
Pareto Optimal Set ◽  
Conflicting Objectives ◽  
Collinearity Diagnostics ◽  
Film Stiffness ◽  
Spiral Grooves

Spiral groove is one of the most common types of structures on gas mechanical seals. Numerical research demonstrated that the grooves designed for improving gas film lift or film stiffness often lead to the leakage increase. Hence, a multi-objective optimization approach specially for conflicting objectives is utilized to optimize the spiral grooves for a specific sample in this study. First, the objectives and independent variables in multi-objective optimization are determined by single objective analysis. Then, a set of optimal parameters, i.e., Pareto-optimal set, is obtained. Each solution in this set can get the highest dimensionless gas film lift under a specific requirement of the dimensionless leakage rate. Finally, the collinearity diagnostics is performed to evaluate the importance of different independent variables in the optimization.

A multi-actor multi-objective optimization approach for locating temporary logistics hubs during disaster response

2018 ◽  
Vol 8 (1) ◽  
pp. 2-21 ◽  
Author(s):  
Rajali Maharjan ◽  
Shinya Hanaoka
Keyword(s):  
Mathematical Model ◽  
Disaster Response ◽  
Decision Makers ◽  
New Method ◽  
Optimization Approach ◽  
Multi Objective Optimization ◽  
Content Type ◽  
Multi Objective ◽  
Multiple Decision Makers ◽  
Relief Distribution

Purpose The purpose of this paper is to develop a mathematical model that determines the location of temporary logistics hubs (TLHs) for disaster response and proposes a new method to determine weights of the objectives in a multi-objective optimization problem. The research is motivated by the importance of TLHs and the complexity that surrounds the determination of their location. Design/methodology/approach A multi-period multi-objective model with multi-sourcing is developed to determine the location of the TLHs. A fuzzy factor rating system (FFRS) under the group decision-making (GDM) condition is then proposed to determine the weights of the objectives when multiple decision makers exist. Findings The interview with decision makers shows the heterogeneity of decision opinions, thus substantiating the importance of GDM. The optimization results provide useful managerial insights for decision makers by considering the trade-off between two non-commensurable objectives. Research limitations/implications In this study, decision makers are considered to be homogeneous, which might not be the case in reality. This study does not consider the stochastic nature of relief demand. Practical implications The outcomes of this study are valuable to decision makers for relief distribution planning. The proposed FFRS approach reveals the importance of involving multiple decision makers to enhance sense of ownership of established TLHs. Originality/value A mathematical model highlighting the importance of multi-sourcing and short operational horizon of TLHs is developed. A new method is proposed and implemented to determine the weights of the objectives. To the best of the authors’ knowledge, the multi-actor and multi-objective aspects of the TLH location problem have not thus far been considered simultaneously for one particular problem in humanitarian logistics.

Multi-objective TMA management optimization using the point merge system

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ramazan Kursat Cecen
Keyword(s):  
Mathematical Model ◽  
Mixed Integer ◽  
Optimization Approach ◽  
Multi Objective Optimization ◽  
Content Type ◽  
Multi Objective ◽  
First Come First Serve ◽  
Management Optimization ◽  
The Mathematical Model ◽  
Single Objective

Purpose The purpose of this study is to provide conflict-free operations in terminal manoeuvre areas (TMA) using the point merge system (PMS), airspeed reduction (ASR) and ground holding (GH) techniques. The objective is to minimize both total aircraft delay (TD) and the total number of the conflict resolution manoeuvres (CRM). Design/methodology/approach The mixed integer linear programming (MILP) is used for both single and multi-objective optimization approaches to solve aircraft sequencing and scheduling problem (ASSP). Compromise programming and ε-constraint methods were included in the methodology. The results of the single objective optimization approach results were compared with baseline results, which were obtained using the first come first serve approach, in terms of the total number of the CRM, TD, the number of aircraft using PMS manoeuvres, ASR manoeuvres, GH manoeuvres, departure time updates and on-time performance. Findings The proposed single-objective optimization approach reduced both the CRM and TD considerably. For the traffic flow rates of 15, 20 and 25 aircraft, the improvement of CRM was 53.08%, 41.12% and 32.6%, the enhancement of TD was 54.2%, 48.8% and 31.06% and the average number of Pareto-optimal solutions were 1.26, 2.22 and 3.87, respectively. The multi-objective optimization approach also exposed the relationship between the TD and the total number of CRM. Practical implications The proposed mathematical model can be implemented considering the objectives of air traffic controllers (ATCOs) and airlines operators. Also, the mathematical model is able to create conflict-free TMA operations and, therefore, it brings an opportunity for ATCOs to reduce frequency occupancy time. Originality/value The mathematical model presents the total number of CRM as an objective function in the ASSP using the MILP approach. The mathematical model integrates ATCOs’ and airline operators’ perspective together with new objective functions.

scholarly journals OPTIMIZATION OF GEOMETRICALLY NONLINEAR LATTICE GIRDERS. PART I: CONSIDERING MEMBER STRENGTHS

2015 ◽  
Vol 21 (4) ◽  
pp. 423-443 ◽  
Author(s):  
Tugrul Talaslioglu
Keyword(s):  
Optimization Algorithm ◽  
Carrying Capacity ◽  
Optimization Approach ◽  
Geometrically Nonlinear ◽  
Load Carrying Capacity ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Load Carrying ◽  
Lattice Girder ◽  
Tubular Lattice

In this study, the entire weight, joint displacements and load-carrying capacity of tubular lattice girders are simultaneously optimized by a multi-objective optimization algorithm, named Non-dominated Sorting Genetic Algorithm II (NSGAII). Thus, the structural responses of tubular lattice girders are obtained by use of arc-length method as a geometrically nonlinear analysis approach and utilized to check their member strengths at each load step according to the provisions of the American Petroleum Institute specification (API RP2A-LRFD 1993). In order to improve the computing capacity of proposed optimization approach, while the optimization algorithm is hybridized with a radial basis neural network approach, an automatic lattice girder generator is included into the design stage. The improved optimization algorithm, called ImpNSGAII, is applied to both a benchmark lattice girder with 17 members and a lattice girder with varying span lengths and loading conditions. Consequently, it is demonstrated: 1) the optimal lattice girder configuration generated has a higher load-carrying capacity ensuring lower weight and joint displacement values; 2) the use of a multi-objective optimization approach increases the correctness degree in evaluation of optimality quality due to the possibility of performing a trade-off analysis for optimal designations; 3) the computing performance of ImpNSGAII is higher than NSGAII’s.

Multi-objective optimization approach to reliability-based robust global optimization of electromagnetic device

2013 ◽  
Vol 33 (1/2) ◽  
pp. 191-200 ◽  
Author(s):  
Ziyan Ren ◽  
Dianhai Zhang ◽  
Chang Seop Koh
Keyword(s):  
Design Sensitivity ◽  
Target System ◽  
Stray Field ◽  
Optimization Approach ◽  
Multi Objective Optimization ◽  
The Finite Element Method ◽  
Content Type ◽  
Multi Objective ◽  
Reliability Based Design ◽  
Design Variables

Purpose – The purpose of this paper is to propose a multi-objective optimization algorithm, which can improve both the performance robustness and the constraint feasibility when the uncertainty in design variables is considered. Design/methodology/approach – Multi-objective robust optimization by gradient index combined with the reliability-based design optimization (RBDO). Findings – It is shown that searching for the optimal design of the TEAM problem 22, which can minimize the magnetic stray field by keeping the target system energy (180 MJ) and improve the feasibility of superconductivity constraint (quenching condition), is possible by using the proposed method. Originality/value – RBDO method applied to the electromagnetic problem cooperated with the design sensitivity analysis by the finite element method.

A new weighted fuzzy programming model for supplier selection and order allocation in the food industry

2020 ◽  
Vol 15 (2) ◽  
pp. 381-406 ◽  
Author(s):  
Mohamad Amin Kaviani ◽  
Alireza Peykam ◽  
Sharfuddin Ahmed Khan ◽  
Nadjib Brahimi ◽  
Raziyeh Niknam
Keyword(s):  
Supplier Selection ◽  
Programming Model ◽  
Fuzzy Programming ◽  
Bottled Water ◽  
Optimization Approach ◽  
Water Production ◽  
Multi Objective Optimization ◽  
Order Allocation ◽  
Content Type ◽  
Multi Objective

Purpose The purpose of this paper is to develop a combined intuitionistic fuzzy analytic hierarchy process (IFAHP) and fuzzy multi-objective optimization approach to select suppliers and allocate the orders to them in the bottled water production context. Design/methodology/approach First, the primary weights of criteria associated with the supplier selection problem are calculated using the IFAHP technique. Then a fuzzy multi-objective optimization model is developed to allocate the appropriate amount of orders to each supplier. Findings The proposed methodology has been successfully implemented in the case of an Iranian food company in its bottled water factory. Results demonstrate our model is capable of practically handling the uncertainty in DMs’ preference that leads to effective and efficient supplier selection and order allocation decisions. Originality/value The authors develop a novel hybrid decision-making tool to tackle the uncertainty in decision-makers’ opinions with a demonstrated applicability and some promising outcomes in efficiently allocating the order quantity to suppliers in the area of bottled water production.

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