Multi-Objective Optimization of Composite Elliptical Submersible Pressure Hull for Minimize the Buoyancy Factor and Maximize Buckling Load Capacity

2014 ◽  
Vol 578-579 ◽  
pp. 75-82 ◽  
Author(s):  
Fathallah Elsayed ◽  
Hui Qi ◽  
Li Li Tong ◽  
Mahmoud Helal
Keyword(s):  
Parametric Design ◽  
Load Capacity ◽  
Buckling Load ◽  
Multi Objective Optimization ◽  
Element Analysis ◽  
Multi Objective ◽  
Design Variables ◽  
Wide Range ◽  
Conflicting Objectives ◽  
Sophisticated Analysis

Due to the wide range of variables involved and sophisticated analysis techniques required, optimum structural design of composite submersible pressure hull is known to be a challenge for designers. The major challenge involved in the coupled design problem is to handle multiple conflicting objectives. The problem with its proper consideration through multi-objective optimization is studied in this paper. Minimize the buoyancy factor and maximize buckling load capacity of the submersible pressure hull under hydrostatic pressure is considered as the objective function to reach the operating depth equal to 6000m. Finite element analysis of composite elliptical submersible pressure hull is performed using ANSYS parametric design language (APDL). The constraints based on the failure strength of the hulls are considered. The fiber orientation angles and the thickness in each layer, the radii of the ellipse, the ring beams and the stringers dimensions are taken as design variables. Additionally, a sensitivity analysis is performed to study the influence of the design variables up on objectives and constraints functions. Results of this study provide a valuable reference for designers of composite underwater vehicles.

The Finite Element Analysis and the Multi-Objective Optimization Design of Spindle Systems of CNC Gantry Machine Tools

2016 ◽  
Vol 693 ◽  
pp. 243-250
Author(s):  
Zhi Zhong Guo ◽  
Yun Shun Zhang ◽  
Shi Hao Liu
Keyword(s):  
Machine Tools ◽  
Optimization Design ◽  
Multi Objective Optimization ◽  
Element Analysis ◽  
Multi Objective ◽  
Vibration Resistance ◽  
Design Variables ◽  
Force Coupling ◽  
The Finite Element Analysis ◽  
Spindle Structure

It is discovered that the vibration resistance of spindle systems needs to be improved based on the statics analysis, modal analysis and heating-force coupling analysis of spindle systems of CNC gantry machine tools. The design variables of optimization are set according to sensitivity analysis, multi-objective and dynamic optimization design is realized and its designing scheme is gained for spindle structure. The research results show that vibration resistance can be improved without change of the quality and static property of spindle systems of CNC gantry machine tools.

Finite Element Modelling and Multi-Objective Optimization of Composite Submarine Pressure Hull Subjected to Hydrostatic Pressure

2019 ◽  
Vol 953 ◽  
pp. 53-58 ◽  
Author(s):  
Elsayed Fathallah
Keyword(s):  
Hydrostatic Pressure ◽  
Parametric Design ◽  
Epoxy Composite ◽  
Load Capacity ◽  
Optimization Process ◽  
Valuable Insight ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Optimized Model ◽  
Better Than

Excellent mechanical behavior and low density of composite materials make them candidates to replace metals for many underwater applications. This paper presents a comprehensive study about the multi-objective optimization of composite pressure hull subjected to hydrostatic pressure to minimize the weight of the pressure hull and maximize the buckling load capacity according to the design requirements. Two models were constructed, one model constructed from Carbon/Epoxy composite (USN-150), the other model is metallic pressure hull constructed from HY100. The analysis and the optimization process were completely performed using ANSYS Parametric Design Language (APDL). Tsai-Wu failure criterion was incorporated in the optimization process. The results obtained emphasize that, the submarine constructed from Carbon/Epoxy composite (USN-150) is better than the submarine constructed from HY100. Finally, an optimized model with an optimum pattern of fiber orientations was presented. Hopefully, the results may provide a valuable insight for the future of designing composite underwater vehicles.

Multi-Objective Optimization of Piezoelectric Actuator Placement for Shape Control of Plates Using Genetic Algorithms

2009 ◽  
Vol 131 (9) ◽  
Author(s):  
Rajesh Kudikala ◽  
Deb Kalyanmoy ◽  
Bishakh Bhattacharya
Keyword(s):  
Optimization Algorithm ◽  
Shape Control ◽  
Optimization Problem ◽  
Piezoelectric Actuators ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Input Control ◽  
Wide Range ◽  
Conflicting Objectives ◽  
Lag Model

Shape control of adaptive structures using piezoelectric actuators has found a wide range of applications in recent years. In this paper, the problem of finding optimal distribution of piezoelectric actuators and corresponding actuation voltages for static shape control of a plate is formulated as a multi-objective optimization problem. The two conflicting objectives considered are minimization of input control energy and minimization of mean square deviation between the desired and actuated shapes with constraints on the maximum number of actuators and maximum induced stresses. A shear lag model of the smart plate structure is created, and the optimization problem is solved using an evolutionary multi-objective optimization algorithm: nondominated sorting genetic algorithm-II. Pareto-optimal solutions are obtained for different case studies. Further, the obtained solutions are verified by comparing them with the single-objective optimization solutions. Attainment surface based performance evaluation of the proposed optimization algorithm has been carried out.

scholarly journals A Holistic Multi-Objective Design Optimization Approach for Arctic Offshore Supply Vessels

2021 ◽  
Vol 13 (10) ◽  
pp. 5550
Author(s):  
Aleksander A. Kondratenko ◽  
Martin Bergström ◽  
Aleksander Reutskii ◽  
Pentti Kujala
Keyword(s):  
Design Optimization ◽  
Case Studies ◽  
Parametric Design ◽  
Optimization Approach ◽  
Multi Objective Optimization ◽  
Abc Algorithm ◽  
Multi Objective ◽  
Bee Colony ◽  
Conceptual Design Phase ◽  
Wide Range

This article presents a new holistic multi-objective design approach for the optimization of Arctic Offshore Supply Vessels (OSVs) for cost- and eco-efficiency. The approach is intended to be used in the conceptual design phase of an Arctic OSV. It includes (a) a parametric design model of an Arctic OSV, (b) performance assessment models for independently operating and icebreaker-assisted Arctic OSVs, and (c) a novel adaptation of the Artificial Bee Colony (ABC) algorithm for multi-objective optimization of Arctic OSVs. To demonstrate the feasibility and viability of the proposed optimization approach, a series of case studies covering a wide range of operating scenarios are carried out. The results of the case studies indicate that the consideration of icebreaker assistance significantly extends the feasible design space of Arctic OSVs, enabling solutions with improved energy- and cost-efficiency. The results further indicate that the optimal amount of icebreaking assistance and optimal vessel speed differs for different vessels, highlighting the motivation for holistic design optimization. The applied adaptation of the ABC algorithm proved to be well suited and efficient for the multi-objective optimization problem considered.

Multi-Objective Optimization of Piezoelectric Actuator Placement for Shape Control of Plate Using Genetic Algorithms

2008 ◽  
Author(s):  
Rajesh Kudikala ◽  
Deb Kalyanmoy ◽  
Bishakh Bhattacharya
Keyword(s):  
Shape Control ◽  
Optimization Problem ◽  
Piezoelectric Actuators ◽  
Multi Objective Optimization ◽  
Nsga Ii ◽  
Multi Objective ◽  
Input Control ◽  
Wide Range ◽  
Conflicting Objectives ◽  
Lag Model

Shape control of adaptive structures using piezoelectric actuators has found a wide range of applications in recent years. In this paper, the problem of finding optimal distribution of piezoelectric actuators and corresponding actuation voltages for static shape control of a plate is formulated as a multi objective optimization problem. Two conflicting objectives: minimization of input control energy and minimization of mean square deviation between the desired and actuated shapes are considered with constraints on maximum number of actuators and maximum induced stresses. A shear lag model of the smart plate structure is created and the optimization problem is solved using an evolutionary multi-objective optimization (EMO) algorithm NSGA-II. Pareto-optimal solutions are obtained for different case studies. Further, the obtained solutions are verified by comparing with single-objective optimization solutions.

MODELING AND MULTI-OBJECTIVE OPTIMIZATION OF FORWARD-CURVED BLADE CENTRIFUGAL FANS USING CFD AND NEURAL NETWORKS

2011 ◽  
Vol 35 (1) ◽  
pp. 63-79 ◽  
Author(s):  
Abolfazl Khalkhali ◽  
Mehdi Farajpoor ◽  
Hamed Safikhani
Keyword(s):  
Neural Networks ◽  
Second Step ◽  
Group Method ◽  
Centrifugal Fan ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Design Variables ◽  
Conflicting Objectives ◽  
Centrifugal Fans ◽  
Curved Blade

In the present study, multi-objective optimization of Forward-Curved (FC) blade centrifugal fans is performed in three steps. In the first step, Head rise (HR) and the Head loss (HL) in a set of FC centrifugal fan is numerically investigated using commercial software NUMECA. Two meta-models based on the evolved group method of data handling (GMDH) type neural networks are obtained, in the second step, for modeling of HR and HL with respect to geometrical design variables. Finally, using the obtained polynomial neural networks, multi-objective genetic algorithms are used for Pareto based optimization of FC centrifugal fans considering two conflicting objectives, HR and HL.

Response Surface Mapping and Multi-Objective Optimization of Crowning and Tapers in Water-Lubricated Thrust Bearings

2019 ◽  
Author(s):  
Xin Deng ◽  
Cori Watson ◽  
Minhui He ◽  
Roger Fittro ◽  
Houston Wood
Keyword(s):  
Film Thickness ◽  
Power Loss ◽  
Performance Metrics ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Design Variables ◽  
Wide Range ◽  
Minimum Film Thickness ◽  
Bearing Design ◽  
The Impact

Abstract Fluid film bearings for turbomachinery are designed to support the loads applied by the rotor system. Oil-lubricated bearings are widely used in high speed rotating machines. However, environmental issues and risk-averse operations have made water lubricated bearings increasingly popular. Due to different viscosity properties between oil and water, the low viscosity of water decreases film thickness significantly. Crowning and tapers are two main ways to maintain the film thickness requirements in water lubrication, but no studies about the influence of these parameters on the film thickness in water-lubricated bearings have been reported. Therefore, further understanding of the performance associated with optimizing the bearing design with different weighted performance and their relationships to bearing design variables could be invaluable to bearing design engineers. This study explores the impact of three crowning and taper design variables on the performance of one tilting pad thrust bearing using the design of experiments techniques applied to a thermoelastohydrodynamic (TEHD) bearing model. The bearing design variables analyzed in this study include the radius of the ground-in crown, taper circumferential angle offset, and the vertical taper distance at the inner and outer radii. Each of the design variables is first varied over five levels, each in central composite design. The outputs from the TEHD numerical simulations used as performance measures for each bearing design point were the minimum film thickness, the film thickness at the pivot location, maximum film pressure and power loss. Multi-objective optimization was performed. A range of weighting parameters was selected for the optimization function to find a bearing design that maintains the minimum film thickness criterion while minimizing power loss. The resulting optimum design points allowed for a comparison between the design optimization at different weightings. This study demonstrates how designers can use these approaches to view the relationships between design variables and important performance metrics to design better bearing for a wide range of applications.

A method for the optimal design of low-density polymer foam core sandwiches using FEA and multiobjective optimization of design variables

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Çağrı Uzay ◽  
Durmuş Can Acer ◽  
Necdet Geren
Keyword(s):  
Optimal Design ◽  
Load Capacity ◽  
Low Density ◽  
Foam Core ◽  
Multi Objective Optimization ◽  
Polymer Foam ◽  
Multi Objective ◽  
The Core ◽  
Design Variables ◽  
Bending Load

Abstract In this study, a generative method was introduced to determine the optimal design of low-density polymer foam core sandwiches using finite element analysis (FEA) and multi-objective optimization of design variables without needing experiments. The method was also assessed. The sandwich structures were designed based on woven plain carbon fiber fabrics, PVC foam core, and polymer epoxy matrix. The design variables are the core density (40, 48, 60 kg/m3) and the core thickness (16, 20, 25 mm). The sandwich configurations were subjected to FEA under the three-point bending (TPB) loads. The force-reaction curves obtained from FEA were compared to experimental data available in the literature. Excellent agreement was achieved between the experimental and FEA simulated results at the linear elastic region of the curves. Thus, it allowed predicting the bending stiffness of the sandwiches via TPB analysis. Besides, a two-way analysis of variance (ANOVA) was conducted to determine the effects of parameters on sandwich mass and bending load capacity. Multi-objective optimization of design variables was also carried out according to the constructed mathematical models. The method provided in this study eases both designer’s and researcher’s work to obtain the optimal design variables without making costly experiments.

Integrated Design and Multi-Objective Optimization of a Single Stage Heat-Pump Turbocompressor

2013 ◽  
Author(s):  
J. Schiffmann
Keyword(s):  
Design Optimization ◽  
High Efficiency ◽  
Integrated Design ◽  
Heat Pumps ◽  
Small Scale ◽  
Multi Objective Optimization ◽  
Design Constraints ◽  
Multi Objective ◽  
Wide Range ◽  
Standard Design

Small scale turbomachines in domestic heat pumps reach high efficiency and provide oil-free solutions which improve heat-exchanger performance and offer major advantages in the design of advanced thermodynamic cycles. An appropriate turbocompressor for domestic air based heat pumps requires the ability to operate on a wide range of inlet pressure, pressure ratios and mass flows, confronting the designer with the necessity to compromise between range and efficiency. Further the design of small-scale direct driven turbomachines is a complex and interdisciplinary task. Textbook design procedures propose to split such systems into subcomponents and to design and optimize each element individually. This common procedure, however, tends to neglect the interactions between the different components leading to suboptimal solutions. The authors propose an approach based on the integrated philosophy for designing and optimizing gas bearing supported, direct driven turbocompressors for applications with challenging requirements with regards to operation range and efficiency. Using previously validated reduced order models for the different components an integrated model of the compressor is implemented and the optimum system found via multi-objective optimization. It is shown that compared to standard design procedure the integrated approach yields an increase of the seasonal compressor efficiency of more than 12 points. Further a design optimization based sensitivity analysis allows to investigate the influence of design constraints determined prior to optimization such as impeller surface roughness, rotor material and impeller force. A relaxation of these constrains yields additional room for improvement. Reduced impeller force improves efficiency due to a smaller thrust bearing mainly, whereas a lighter rotor material improves rotordynamic performance. A hydraulically smoother impeller surface improves the overall efficiency considerably by reducing aerodynamic losses. A combination of the relaxation of the 3 design constraints yields an additional improvement of 6 points compared to the original optimization process. The integrated design and optimization procedure implemented in the case of a complex design problem thus clearly shows its advantages compared to traditional design methods by allowing a truly exhaustive search for optimum solutions throughout the complete design space. It can be used for both design optimization and for design analysis.

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