A Hydrodynamic Preliminary Design Optimization Framework for High Speed Planing Craft

2012 ◽  
Vol 56 (01) ◽  
pp. 35-47
Author(s):  
Ahmad F. Mohamad Ayob ◽  
Ahmad F. Mohamad Ayob ◽  
Tapabrata Ray ◽  
Warren Smith
Keyword(s):  
Design Optimization ◽  
High Speed ◽  
Ship Design ◽  
Design Stage ◽  
Preliminary Design ◽  
Planing Craft ◽  
Performance Targets ◽  
Optimization Framework ◽  
Design Variables ◽  
Performance Estimates

Ship design optimization in preliminary design stage aims to identify optimum vessel dimensions based on performance targets and design constraints simultaneously. Although vast amount of designs have been generated and evaluated since the application of optimization approaches to ship design, only a few of such designs have been built or "dissected" to gain a deeper understanding as to why such designs tend to be optimal. In this paper an optimization framework is introduced for the design of high speed planing craft, which consists of a geometry module, standard performance estimates, and a suite of state-of-the-art optimization algorithms. Single and multiobjective optimization problem formulations are solved using the framework. Designs identified through the process of optimization are further analyzed to uncover relationships among the design variables that lead to better designs. An important contribution of this paper is to illustrate the steps involved in deriving pseudo performance estimates and their utility in the context of preliminary design where such relationships can be effectively and efficiently used to sieve through a large number of designs.

A Hydrodynamic Preliminary Design Optimization Framework for High Speed Planing Craft

2012 ◽  
Vol 56 (1) ◽  
pp. 35-47 ◽  
Author(s):  
Ahmad F. Mohamad Ayob ◽  
Tapabrata Ray ◽  
Warren Smith
Keyword(s):  
Design Optimization ◽  
High Speed ◽  
Preliminary Design ◽  
Planing Craft ◽  
Optimization Framework

scholarly journals FEM Based Preliminary Design Optimization in Case of Large Power Transformers

2019 ◽  
Author(s):  
Tamás Orosz ◽  
David Pánek ◽  
Pavel Karban
Keyword(s):  
Design Optimization ◽  
Design Process ◽  
Optimization Problems ◽  
Optimization Method ◽  
Power Transformers ◽  
Design Stage ◽  
Preliminary Design ◽  
Large Power ◽  
Custom Made ◽  
Transformer Design

Since large power transformers are custom-made, and their design process is a labor-intensive task, their design process is split into different parts. In tendering, the price calculation is based on the preliminary design of the transformer. Due to the complexity of this task, it belongs to the most general branch of discrete, non-linear mathematical optimization problems. Most of the published algorithms are using a copper filling factor based winding model to calculate the main dimensions of the transformer during this first, preliminary design step. Therefore, these cost optimization methods are not considering the detailed winding layout and the conductor dimensions. However, the knowledge of the exact conductor dimensions is essential to calculate the thermal behaviour of the windings and make a more accurate stray loss calculation. The paper presents a novel, evolutionary algorithm-based transformer optimization method which can determine the optimal conductor shape for the windings during this examined preliminary design stage. The accuracy of the presented FEM method was tested on an existing transformer design. Then the results of the proposed optimization method have been compared with a validated transformer design optimization algorithm.

Standard Outfit Package Units in the LPD 17 Ship Design: A Production Impact Study

1995 ◽  
Vol 11 (04) ◽  
pp. 252-263
Author(s):  
Walter L. Christensen ◽  
Philip C. Koenig
Keyword(s):  
Production Scheduling ◽  
Ship Design ◽  
Design Stage ◽  
Traditional Practices ◽  
Preliminary Design ◽  
Wide Range ◽  
Preliminary Design Stage ◽  
And Performance ◽  
Assessment Problems ◽  
Material Ordering

Standard outfit package units for reverse osmosis plants, fire pumps, steering gear, and sanitary spaces were proposed for the LPD 17 amphibious transport dock ship design. The ship was in the preliminary design stage, and it was necessary to determine how this shift to outfit modularity would affect the ship procurement program. Because the use of package units would not have a significant impact on the overall characteristics and performance of the ship, the focus of the investigation was on material ordering and production scheduling. The analysis took account of zone-area-stage outfitting methods and also more traditional practices. With either approach, it was found that the package units did not present any schedule or procurement problems This particular study was focused on a very specific issue, but the approach is applicable to a wide range of production impact assessment problems.

Design-airworthiness integration method for general aviation aircraft during early development stage

2019 ◽  
Vol 91 (7) ◽  
pp. 1067-1076
Author(s):  
Maxim Tyan ◽  
Jungwon Yoon ◽  
Nhu Van Nguyen ◽  
Jae-Woo Lee ◽  
Sangho Kim
Keyword(s):  
Design Optimization ◽  
Design Stage ◽  
Design Parameters ◽  
Design Framework ◽  
Efficient Design ◽  
Content Type ◽  
Early Design ◽  
Early Design Stage ◽  
Optimization Framework ◽  
Design Requirements

Purpose Major changes of an aircraft configuration are conducted during the early design stage. It is important to include the airworthiness regulations at this stage while there is extensive freedom for designing. The purpose of this paper is to introduce an efficient design framework that integrates airworthiness guidelines and documentation at the early design stage. Design/methodology/approach A new design and optimization process is proposed that logically includes the airworthiness regulations as design parameters and constraints by constructing a certification database. The design framework comprises requirements analysis, preliminary sizing, conceptual design synthesis and loads analysis. A design certification relation table (DCRT) describes the legal regulations in terms of parameters and values suitable for use in design optimization. Findings The developed framework has been validated and demonstrated for the design of a Federal Aviation Regulations (FAR) 23 four-seater small aircraft. The validation results show an acceptable level of accuracy to be applied during the early design stage. The total mass minimization problem has been successfully solved while satisfying all the design requirements and certification constraints specified in the DCRT. Moreover, successful compliance with FAR 23 subpart C is demonstrated. The proposed method is a useful tool for design optimization and compliance verifications during the early stages of aircraft development. Practical implications The new certification database proposed in this research makes it simpler for engineers to access a large amount of legal documentation related to airworthiness regulations and provides a link between the regulation text and actual design parameters and their bounds. Originality/value The proposed design optimization framework integrates the certification database that is built of several types of legal documents such as regulations, advisory circulars and standards. The Engineering Requirements and Guide summarizes all the documents and design requirements into a single document. The DCRT is created as a summary table that indicates the design parameters affected by a given regulation(s), the design stage at which the parameter can be evaluated and its value bounds. The introduction of the certification database into the design optimization framework significantly reduces the engineer’s load related for airworthiness regulations.

An application of Taguchi method on the high-speed motorized spindle system design

2011 ◽  
Vol 225 (9) ◽  
pp. 2198-2205 ◽  
Author(s):  
C-W Lin
Keyword(s):  
Optimal Design ◽  
Taguchi Method ◽  
Machine Tool ◽  
High Speed ◽  
Signal To Noise Ratio ◽  
Design Stage ◽  
Original Design ◽  
Spindle System ◽  
Design Engineers ◽  
Design Variables

As spindle speeds increase, the variations caused by high-speed effects become more significant. Therefore, in the initial design stage, it is necessary for machine tool design engineers to construct a robust high-speed machine tool that possesses high first-mode natural frequencies (FMNFs) and is insensitive to high operating speeds. In this article, Taguchi method is used to identify the optimal values of design variables (DVs) for a robust high-speed spindle system with respect to the signal-to-noise ratio (SNR) of system FMNF. The L18 orthogonal array covers seven main DVs at three levels each, one main DV at two levels, and the noise factor spindle speeds at six levels. The results show that the new optimal design has improved the SNR of the FMNF by 2.06 dB from the original design; this implies that the quality loss has been reduced to 62 per cent of its original value. The optimal design has been verified by a confirmation numerical experiment.

scholarly journals Preliminary Sub-Systems Design Integrated in a Multidisciplinary Design Optimization Framework

2017 ◽  
Vol 2017 (4) ◽  
pp. 9-23
Author(s):  
Marco Fioriti ◽  
Luca Boggero ◽  
Sabrina Corpino
Keyword(s):  
Design Optimization ◽  
Multidisciplinary Design Optimization ◽  
Systems Design ◽  
Aircraft Design ◽  
Multidisciplinary Design ◽  
Design Parameters ◽  
Preliminary Design ◽  
Horizon 2020 ◽  
Optimization Framework ◽  
Complex Subject

Abstract The aircraft design is a complex subject since several and completely different design disciplines are involved in the project. Many efforts are made to harmonize and optimize the design trying to combine all disciplines together at the same level of detail. Within the ongoing AGILE (Horizon 2020) research, an aircraft MDO (Multidisciplinary Design Optimization) process is setting up connecting several design tools and competences together. Each tool covers a different design discipline such as aerodynamics, structure, propulsion and systems. This paper focuses on the integration of the sub-system design discipline with the others in order to obtain a complete and optimized aircraft preliminary design. All design parameters used to integrate the sub-system branch with the others are discussed as for their redefinition within the different detail level of the design.

scholarly journals Numerical Simulation of Seakeeping Performance on the Preliminary Design of a Semi-Planing Craft

2019 ◽  
Vol 7 (7) ◽  
pp. 199 ◽  
Author(s):  
Yu-Hsien Lin ◽  
Chia-Wei Lin
Keyword(s):  
High Speed ◽  
Route Planning ◽  
Test Cases ◽  
Preliminary Design ◽  
Sea State ◽  
Planing Craft ◽  
High Speeds ◽  
Motion Responses ◽  
Seakeeping Performance ◽  
The Difference

This study established a seakeeping program to evaluate the motion responses of a high speed semi-planing craft and to develop a database for future route planning. A series 62 mono-hull was chosen for the test cases, comparing seakeeping performances with full-scale on-board measurements. The statistical results were obtained using spectral analysis, which combines the International Towing Tank Conference (ITTC) spectrum with the response amplitude operator (RAO) responses of each wave heading for a given sailing speed. The speed polar diagram was made to illustrate five degree-of-freedom (DOF) motion responses between sailing speeds and wave heading angles in a particular sea state. Although the craft has different trim angles at high speeds (because of dynamic lift) under various loading and draft conditions, this study only investigated the trim angles of 0° (even keel), 1° by the stern, and 2° by the stern, to understand the difference between their seakeeping performances. The results in this study provide a useful guideline for evaluating operational regulations and safety for high speed semi-planing crafts in the future.

Didactical Tool for Wing Weight Estimation in a Preliminary Aircraft Design Stage

2021 ◽  
Vol 18 ◽  
pp. 60-65
Author(s):  
Giacomo Frulla
Keyword(s):  
Aircraft Design ◽  
General Aviation ◽  
Design Stage ◽  
Preliminary Design ◽  
Weight Estimation ◽  
Simple Assumption ◽  
Weight Variation ◽  
Design Variables ◽  
Starting Point ◽  
Preliminary Design Stage

Aircraft preliminary design requires a lot of complex evaluations and assumptions related to design variables that are not completely known at a very initial stage. Didactical activity becomes unclear since students ask for precise values in the starting point. A tentative in providing a simple tool for wing weight estimation is presented devoted to overcome these common difficulties and clarifies the following points: a) the intrinsic iterative nature of the preliminary design stage, b) provide useful and realistic calculation for the wing weight with very simple assumption not covered by cumbersome calculations and formulas. The procedure is applied to the calculation of wing weight for a typical general aviation aircraft in the preliminary design stage. The effect of the main variables on the wing weight variation is also presented confirming well-known results from literature and design manuals.

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