Hull form uncertainty optimization design for minimum EEOI with influence of different speed perturbation types

2017 ◽  
Vol 140 ◽  
pp. 66-72 ◽  
Author(s):  
Yuan Hang Hou
Keyword(s):  
Optimization Design ◽  
Hull Form ◽  
Uncertainty Optimization

CFD Based Multi-Disciplinary Optimization Design of High-Performance Deep Sea Seismic Vessel

2017 ◽  
Author(s):  
Mao Xiaofei ◽  
Zhang Wenxu ◽  
Qian Jiankui ◽  
Wu Minghao
Keyword(s):  
High Performance ◽  
Optimization Design ◽  
Optimal Solution ◽  
Solution Set ◽  
Short Term ◽  
Hull Form ◽  
Optimal Solution Set ◽  
Computational Fluid Dynamics Cfd ◽  
The Stability

This paper focuses on the application of a ship hull form multi-disciplinary optimization (MDO) system based on the computational fluid dynamics (CFD). Using the iSIGHT software, the MDO system integrates an automatic geometry transformation program and high-fidelity CFD solvers for different sub-disciplines. Hydrodynamics analysis subsystem includes resistance, seakeeping and stability modules. The resistance and seakeeping is analyzed by commercial potential-flow CFD codes, the stability is assessed by in-house code. The geometry variation output can be automatically used by the numerical solvers. By means of the design of experiment (DOE) technique, a neural network metamodel is trained to predict short term motion response of the derived ships efficiently. The system has been used in a seismic vessel’s hull form optimization to minimize the resistance and maximize the long term seakeeping operability index. Meanwhile, the stability in waves is concerned as a constraint. The hybrid MIGA-NLPQL optimization algorithm is applied for a global-to-local search in resistance optimization. For the synthesis optimization, a Pareto optimal solution set has been obtained and the final solution is achieved by trade-off analysis of the solution set. The entire automatic optimization process can be used for the preliminary design of new high performance vessels.

scholarly journals Optimization Design of Minimum Total Resistance Hull Form Based on CFD Method

2018 ◽  
Vol 32 (3) ◽  
pp. 323-330 ◽  
Author(s):  
Bao-ji Zhang ◽  
Sheng-long Zhang ◽  
Hui Zhang
Keyword(s):  
Optimization Design ◽  
Total Resistance ◽  
Hull Form ◽  
Cfd Method

Uncertainty Optimization Design of Vehicle Wheel Made of Long Glass Fiber Reinforced Thermoplastic

2018 ◽  
Author(s):  
Daijun Hu ◽  
Yingchun Shan ◽  
Xiandong Liu ◽  
Weihao Chai ◽  
Xiaoyin Wang
Keyword(s):  
Glass Fiber ◽  
Optimization Design ◽  
Mechanical Performance ◽  
Thermoplastic Composite ◽  
Fiber Reinforced ◽  
Effective Measure ◽  
Glass Fiber Reinforced ◽  
Uncertainty Optimization ◽  
Long Glass Fiber ◽  
Simulation Results

The use of automobile lightweight is an effective measure to reduce energy consumption and vehicle emissions. The utilization of high-performance composite materials is an important way to achieve lightweight vehicles technically. The advantages of using thermoplastic composite wheels are: easy to form, high manufacturing efficiency, low cost and easy to recycle. This leads to broader application prospects. Taking composite anisotropy into consideration, the mechanical performance of a wheel made of long glass fiber reinforced thermoplastic (LGFT), is analysed using the finite element method (FEM). This is done by placing the wheel under a bending fatigue load simulation. According to the simulation results, the sample database is established by orthogonal experimental method on the Isight platform, and the approximate model is established by the Response Surface Methodology (RSM). Based on this model, uncertainty optimization analysis is then conducted on the wheel’s design using Sigma Principle whereby the optimization target is the mass minimization. The maximum deformation of the wheel and the stress on both sides of the spoke will serve as constraint conditions and the key dimension parameters of the wheel model will be taken as the design variables. The uncertainty optimization is based on the Sigma criterion, taking into consideration the wheel’s geometry and property-fluctuation materials. The feasibility of design schemes is then verified after comparison analysis between the optimization results and the simulation results obtained. The result shows that compared with deterministic optimization, though the weight of the wheel has slightly increased, the uncertainty optimization based on the Sigma criterion is much more robust and the reliabilities of the three constraints are all above 6 Sigma. The resulting optimized LGFT wheel weighs 5.28kg, which has a 5.5% more loss in weight than the initial target and is also 25.6% lighter than the counterpart wheel which is made of aluminum alloy. The desired design results is now achieved with this lightweight effect.

Uncertainty Optimization Design of a Vehicle Body Structure Considering Random Deviations

2018 ◽  
Vol 1 (4) ◽  
pp. 342-351
Author(s):  
Jianhua Zhou ◽  
Fengchong Lan ◽  
Jiqing Chen ◽  
Fanjie Lai
Keyword(s):  
Optimization Design ◽  
Vehicle Body ◽  
Body Structure ◽  
Uncertainty Optimization

Numerical and experimental study on hydrodynamic bulbous bow hull-form optimization for various service conditions due to slow steaming of container vessel

2018 ◽  
Vol 233 (4) ◽  
pp. 1103-1122
Author(s):  
Xun-bin Yin ◽  
Yu Lu ◽  
Jin Zou ◽  
Lei Wan
Keyword(s):  
Optimization Design ◽  
Optimization Technique ◽  
Experimental Studies ◽  
Design Stage ◽  
Probability Density Distribution ◽  
Hull Form ◽  
Slow Steaming ◽  
Service Conditions ◽  
Bulbous Bow ◽  
Hydrodynamic Optimization

In this article, an innovative hydrodynamic optimization design of bulbous bow hull-form under various service conditions resulting from the slow steaming of container vessel is presented, improving the overall performances for the real multi-variant usage situations more practical than the single specification of design, which includes both numerical computation and experimental validation. Effects of slow steaming–based statistical analysis of the actual operative occurrence during the lifetime is conducted, obtaining a combined probability density distribution of speed and displacement ushering in the evaluation of objective function. Three main component elements of the hydrodynamic optimization procedure that comprises parametric design of bulbous bow hull-form variation part, hydrodynamic numerical solver part, and optimization technique part are established and integrated. The proposed optimization process is subsequently applied to find the optimal bulbous bow of a container carrier for the hipping demand of different speeds and displacement distributed utilization, reducing significantly total conditions resistance of the hull, on a higher level decreasing the operative cost as well as gas emissions of the ship. Finally, there is an experimental campaign carried out between the optimal and original models to validate the numerical optimization computations. The compared investigation has provided a good agreement from the perspective of both numerical and experimental studies, as a result confirming the success of the present optimization framework and the utility value of the proposed optimization consideration on various service conditions during ship design stage.

Hull Form Optimization Based on an NM+CFD Integrated Method for KCS

2020 ◽  
Vol 17 (10) ◽  
pp. 2050008
Author(s):  
Aiqin Miao ◽  
Decheng Wan
Keyword(s):  
Optimization Design ◽  
Model Building ◽  
Computational Cost ◽  
Hull Form ◽  
Integrated Method ◽  
Computational Fluid Dynamics Cfd ◽  
Hull Forms ◽  
Main Components ◽  
Hydrodynamic Optimization ◽  
High Computational Cost

This paper concerns development and illustration of a hydrodynamic optimization tool, OPTShip-SJTU, which contains four main components, i.e., hull form modifier, performance evaluator, surrogate model building, and optimizer module. It has been further developed by integrating a new method into the performance evaluator module, which combines the Neumann–Michell (NM) theory with computational fluid dynamics (CFD) technology, in order to reduce the high computational cost. To illustrate the practicality of further extension, OPTShip-SJTU was applied to optimize the hull form of KCS by simultaneously reducing drags at two speeds. A drag reduction was obtained by the optimal KCS of different hull forms. It turns out the presented method for ship optimization design is effective and reliable.

Kriging-Based Surrogate Model Combined With Weighted Expected Improvement for Ship Hull Form Optimization

2018 ◽  
Author(s):  
Xinwang Liu ◽  
Decheng Wan ◽  
Gang Chen
Keyword(s):  
Surrogate Model ◽  
Optimization Design ◽  
Global Optimum ◽  
Ship Hull ◽  
Expected Improvement ◽  
Training Dataset ◽  
Efficient Global Optimization ◽  
Sample Point ◽  
Hull Form ◽  
Space Design

The paper explores Kriging-based surrogate model combined with Weighted Expected Improvement approach and for the ship hull form optimization. The training dataset of the Kriging-based surrogate model is obtained by sampling the design space (Design of Experiments, DOE) and performing expensive high-fidelity computations on the selected points. Expected Improvement (EI) is used as a criterion to select one additional sample point in each iteration. The Weighted Expected Improvement (WEI) is derived from EI by adding a tunable parameter which can adjust the weights on exploration and exploitation in the Efficient Global Optimization (EGO). The proposed method selects more than one new sample point by changing the weight parameter for each optimization iteration, thus it can be performed by parallel computation or multi-computer runs which improves the computational efficiency distinctly. This makes it possible not only to improve the accuracy of the surrogate model, but also to explore the global optimum much more quickly. The present method is applied to mathematical test function and a ship hull form optimization design in order to find the optimal hull form with best resistance performance in calm water in different speeds. The result shows that the criterion of WEI can be applied in EGO for optimization design and can be easily extended to other hull form optimization design problems based on computational fluid dynamics.

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