Escort Tug Hydrodynamic Forces Estimation in a Design Framework: From Model Test to Manoeuvrability Simulation

2018 ◽  
Author(s):  
Benedetto Piaggio ◽  
Michele Viviani ◽  
Michele Martelli
Keyword(s):  
Model Test ◽  
Hydrodynamic Forces ◽  
Design Approach ◽  
Fundamental Importance ◽  
Design Stage ◽  
Design Framework ◽  
Early Design ◽  
Early Design Stage ◽  
Smart Control ◽  
Key Features

The manoeuvring capabilities of an escort tug are essential key-features with a view to an all-around design approach devoted to an optimum oriented framework. From the hull geometry settlement and propulsive solution definition, the ability to predict thoroughly the operative life in terms of handling, effectiveness, and safety becomes fundamental, even more with the perspective of developing smart control logics supporting the masters. With such an aim, the availability of a reliable manoeuvrability model is of fundamental importance. In this context, it is important to define an optimum set of captive manoeuvrability tests, whether experimental or numerical, in order to correctly identify the vessel escort performances in simulation; this, always keeping in mind the necessity to limit the effort in view of an application at an early-design stage. Starting from a wide experimental matrix, purposely designed and realized, the present investigation focuses on the quality and robustness of the different regression manoeuvrability models by letting vary the subsets of tests, in order to determine, finally, which is the most suitable hull model to be adopted and which is the minimum set to be performed.

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.

Determination of Hydrodynamic Masses and Roll Periods of Ships in Shallow Water

2021 ◽  
Author(s):  
Larissa Jannsen ◽  
Stefan Krüger
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Hydrodynamic Forces ◽  
Ship Design ◽  
Design Stage ◽  
Ship Motions ◽  
Design Environment ◽  
Early Design ◽  
Early Design Stage ◽  
Water Effects

Abstract Due to the fast increase of the vessels’ size over the past few years the actual water depth is becoming more and more relevant for seakeeping problems. The highly frequented sea route TSS Terschelling – German Bight for example is a shallow water route for large vessels which are now affected by the reduced keel clearance. Many shallow water depth areas occur also in coastal areas or inland seas. If a vessel is travelling in shallow water sea states, the hydrodynamic forces will change compared to deep water sea states and they are essential for further seaway calculations. Furthermore, a rough but easy evaluation of the incoming seaway is the roll period. Shallow water effects should be taken into account for calculating roll periods and thereby predicting a manageable or risky seaway situation. This paper presents the implementation of shallow water effects into an existing 2D panel code. With this panel code the hydrodynamic forces for the vessel’s frames are calculated based on the potential theory in the frequency domain, which is a validated approach in the early design stage. The panel code is part of the ship design environment E4 which is being developed by the Institute of Ship Design and Ship Safety, among others. With the expanded method it is possible to calculate hydrodynamic forces also in shallow water in all degrees of freedom. Therefore, the frame motions are converted to global ship motions. Furthermore, for the usage in the early design stage the calculations should be fast but also accurate. The obtained calculation results are therefore validated with full scale measurement using Inertial-Measurement-Units.

Identification of Human Errors During Early Design Stage Functional Failure Analysis

2018 ◽  
Author(s):  
Lukman Irshad ◽  
Salman Ahmed ◽  
Onan Demirel ◽  
Irem Y. Tumer
Keyword(s):  
Failure Analysis ◽  
Human Error ◽  
System Level ◽  
Design Stage ◽  
Human Factors Engineering ◽  
Human Errors ◽  
Functional Failure ◽  
Early Design ◽  
Early Design Stage ◽  
Early Design Stages

Detection of potential failures and human error and their propagation over time at an early design stage will help prevent system failures and adverse accidents. Hence, there is a need for a failure analysis technique that will assess potential functional/component failures, human errors, and how they propagate to affect the system overall. Prior work has introduced FFIP (Functional Failure Identification and Propagation), which considers both human error and mechanical failures and their propagation at a system level at early design stages. However, it fails to consider the specific human actions (expected or unexpected) that contributed towards the human error. In this paper, we propose a method to expand FFIP to include human action/error propagation during failure analysis so a designer can address the human errors using human factors engineering principals at early design stages. To explore the capabilities of the proposed method, it is applied to a hold-up tank example and the results are coupled with Digital Human Modeling to demonstrate how designers can use these tools to make better design decisions before any design commitments are made.

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