A Fast Method for the Evaluation of the Dynamic Positioning Capability in Time Domain in the Early Design Stage

2015 ◽  
Author(s):  
Adele Luebcke ◽  
Philip Augener ◽  
Arne Falkenhorst
Keyword(s):  
Time Domain ◽  
Wind Waves ◽  
Ship Design ◽  
Propulsion System ◽  
Design Stage ◽  
Maximum Deviation ◽  
Dynamic Positioning ◽  
Fast Method ◽  
Fast Calculation ◽  
Early Design Stage

Vessels equipped with a Dynamic Positioning (DP) system for station keeping have become quite common on the offshore market. The propulsion system of such ships has the capability to compensate the counteracting environmental forces caused by wind, waves and current. Since the DP capability is an important part of the specification, it is necessary to consider this aspect in the early ship design stage. For this purpose a procedure of a fast calculation method is developed by the authors to predict the limiting environmental conditions and the maximum deviation of the position and the course angle for a pre-established propulsion system.

Computation of Drift Forces for Dynamic Positioning Within the Very Early Design Stage of Offshore Wind Farm Installation Vessels

2014 ◽  
Author(s):  
Philip H. Augener ◽  
Stefan Krüger
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Offshore Wind ◽  
Irregular Waves ◽  
Design Stage ◽  
Dynamic Positioning ◽  
Offshore Wind Farm ◽  
Early Design ◽  
Early Design Stage ◽  
Drift Forces

The German government has decided upon the changeover from fossil and nuclear based electrical power generation to renewable energies. Following from this offshore wind farms are erected in the exclusive economic zones of Germany. For the transportation and installation as well as the maintenance of the wind turbine generators very specialized vessels are needed. The capability of dynamic positioning even in very harsh weather conditions is one of the major design tasks for these vessels. For this reason it is important to know the external loads on the ships during station keeping already in the very early design stage. This paper focuses on the computation of wave drift forces in regular and irregular waves as well as in natural seaway. For validation the results of the introduced calculation procedure are compared to measured drift force data from sea-keeping tests of an Offshore Wind Farm Transport and Installation Vessel.

Calculation of the Dynamic Positioning Capability of an Offshore Wind Farm Vessel During the Jack-Up Process in the Early Design Stage

2019 ◽  
Author(s):  
Maximilian Liebert
Keyword(s):  
Wind Farm ◽  
Offshore Wind ◽  
Design Stage ◽  
Force Model ◽  
Dynamic Positioning ◽  
The European Union ◽  
Early Design ◽  
Early Design Stage ◽  
Offshore Industry ◽  
Jack Up

Abstract As a consequence of the planned exit from fossil-based energy in the European Union the exploitation of renewable energies has become a major aspect of the Offshore Industry. Especially the construction and operation of offshore wind energy turbines pose a challenge which is met by the use of jack-up vessels with extendible legs. In order to dimension the vessel’s manoeuvring devices in the early design stage and to ensure a safe jack-up process for given environmental loads the dynamic positioning capability during the jacking including the influence of the legs has to be calculated. As part of the development of a holistic dynamic analysis this paper presents the implementation of the legs’ influence in an existing manoeuvring method. The manoeuvring method solves the equations of motion in three degrees of freedom (surge, sway, yaw). It is based on a force model which comprises various modular components. Therefore another component for the leg-forces is added. A Morison approach is chosen to calculate the hydrodynamic forces on the cylindrical legs. The legs’ hydrodynamic added masses are accounted for and added to the hull’s inertial terms. The benefit of the presented method is the possibility to calculate the dynamic positioning capability with extended legs without being dependent on the results of either time-consuming or non-specific model tests. Therefore the method represents a fast computing tool to design the vessel for the specific environmental conditions of the site of operation.

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.

A Method to Estimate Slamming Characteristics for Ship Design

1971 ◽  
Vol 8 (02) ◽  
pp. 219-232
Author(s):  
M. K. Ochi ◽  
L. E. Motter
Keyword(s):  
Extreme Values ◽  
Operation Time ◽  
Ship Design ◽  
Regression Equation ◽  
Impact Pressure ◽  
Design Stage ◽  
Early Design Stage ◽  
Safe Navigation ◽  
Estimate Frequency ◽  
Ship Operation

This paper discusses a method to estimate slamming characteristics of a ship at an early design stage using the ship lines. The first section of the paper deals with the derivation of a regression equation which yields a coefficient necessary to estimate impact pressure for any given hull form. The second section discusses the procedure of application of the regression equation in conjunction with other computer programs to estimate frequency and severity of slamming for ship design. As an example of the application, the extreme values of impact pressure are computed at several forward stations of the Mariner as a function of ship operation time in various sea states. By assigning an allowable extreme pressure magnitude and tolerable number of slams, it is possible to estimate the limiting sea state or limiting ship speed below which safe navigation without seriously suffering from slamming is anticipated.

Development of a Simulation Environment for Hybrid Propulsion Drive Trains: Utilization of a Holistic Approach to Predict the Dynamic Behavior in the Early Design Stage

2020 ◽  
Author(s):  
Leif-Erik Jannsen
Keyword(s):  
Dynamic Behavior ◽  
System Simulation ◽  
Propulsion System ◽  
Plant Performance ◽  
Design Stage ◽  
Simulation Environment ◽  
Substantial Impact ◽  
Hybrid Propulsion ◽  
Early Design ◽  
Early Design Stage

Abstract This paper covers the generic procedure for the creation and usage of a complete system simulation for propulsion systems of ships with focus on complex hybrid systems. Due to the large number of available components and challenging operational profiles, there is no longer a single best solution, especially in specialized shipbuilding. On top of that even minor changes in the propulsion system can have a substantial impact on plant performance and vessel behavior. Thus, the early design stage is crucial. The design procedure usually incorporates the selection and dimensioning of available components and concepts. Once this has been done, the dynamic behavior can be analyzed using the developed system simulation environment. With the knowledge gained the needed alterations in the concept can be identified and implemented in the subsequent design iteration circle. Based on the example of an offshore anchor handling vessel, the integration potential of a hybrid propulsion system is examined and evaluated according to the aforementioned procedure. The applied tool is a system simulation environment developed in the Department of Marine Engineering, consisting of a distributed co-simulation of the existing ship design environment E4 and Matlab® Simulink®.

scholarly journals Dynamic positioning analysis and comfort assessment for the early design stage of large yachts

2021 ◽  
pp. 1-28
Author(s):  
Francesco Mauro ◽  
Aron Benci ◽  
Victor Ferrari ◽  
Enrico Della Valentina
Keyword(s):  
Design Stage ◽  
Ship Motions ◽  
Dynamic Positioning ◽  
Early Design ◽  
Dynamic Positioning System ◽  
Early Design Stage ◽  
Static Approach ◽  
Offshore Industry ◽  
Positioning Analysis ◽  
Sea Area

In some specific environmentally protected areas, conventional mooring systems cannot be used by large yachts for stationing at anchor and therefore, the adoption of a dynamic positioning system is required. It becomes then necessary to evaluate the station keeping capabilities of a yacht since the early-design stage. Adopting a quasi-static approach, it is possible to perform a standard capability analysis, as commonly done for the offshore industry, obtaining a capability plot as output. However, capability plots are referring to specific wind-wave correlation that are not covering all the possible wave combinations present in a sea area. Here, it is proposed to use a scatter diagram approach for the dynamic positioning analysis of a large yacht, considering the specific sea areas where the yacht shall operate, in order to figure out the downtime period of the DP system per each sea area. The proposed method can be coupled with traditional ship motions analysis, leading to a combination between comfort assessment and DP predictions. In the present work, use has been made of a traditional displacement yacht 72 m long, comparing five different DP system configurations and evaluating an enhanced comfort ranking combining ISO AWI-22834 guidelines for large yachts with ISO AWI-22822 DP analysis.

scholarly journals TRACING THE EMERGENCE OF DESIGN PROBLEMS AND THEIR IMPACTS ON THE COMPLEXITY OF ENGINEERING SOLUTIONS

2021 ◽  
Vol 1 ◽  
pp. 3229-3238
Author(s):  
Torben Beernaert ◽  
Pascal Etman ◽  
Maarten De Bock ◽  
Ivo Classen ◽  
Marco De Baar
Keyword(s):  
Large Scale ◽  
Fusion Reactor ◽  
Design Stage ◽  
Engineering Model ◽  
Design Problems ◽  
Nuclear Fusion Reactor ◽  
Early Design Stage ◽  
Iterative Design ◽  
Problems And Solutions ◽  
Emergent Design

AbstractThe design of ITER, a large-scale nuclear fusion reactor, is intertwined with profound research and development efforts. Tough problems call for novel solutions, but the low maturity of those solutions can lead to unexpected problems. If designers keep solving such emergent problems in iterative design cycles, the complexity of the resulting design is bound to increase. Instead, we want to show designers the sources of emergent design problems, so they may be dealt with more effectively. We propose to model the interplay between multiple problems and solutions in a problem network. Each problem and solution is then connected to a dynamically changing engineering model, a graph of physical components. By analysing the problem network and the engineering model, we can (1) derive which problem has emerged from which solution and (2) compute the contribution of each design effort to the complexity of the evolving engineering model. The method is demonstrated for a sequence of problems and solutions that characterized the early design stage of an optical subsystem of ITER.

scholarly journals Hospital Construction Cost Affecting Their Lifecycle: An Italian Overview

Healthcare ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 888
Author(s):  
Leopoldo Sdino ◽  
Andrea Brambilla ◽  
Marta Dell’Ovo ◽  
Benedetta Sdino ◽  
Stefano Capolongo
Keyword(s):  
Healthcare Services ◽  
Construction Cost ◽  
Design Stage ◽  
Quality Healthcare ◽  
Healthcare Facilities ◽  
Early Design Stage ◽  
Hospital Facility ◽  
Italian Context ◽  
The Cost ◽  
Cost Components

The need for 24/7 operation, and the increasing requests of high-quality healthcare services contribute to framing healthcare facilities as a complex topic, also due to the changing and challenging environment and huge impact on the community. Due to its complexity, it is difficult to properly estimate the construction cost in a preliminary phase where easy-to-use parameters are often necessary. Therefore, this paper aims to provide an overview of the issue with reference to the Italian context and proposes an estimation framework for analyzing hospital facilities’ construction cost. First, contributions from literature reviews and 14 case studies were analyzed to identify specific cost components. Then, a questionnaire was administered to construction companies and experts in the field to obtain data coming from practical and real cases. The results obtained from all of the contributions are an overview of the construction cost components. Starting from the data collected and analyzed, a preliminary estimation tool is proposed to identify the minimum and maximum variation in the cost when programming the construction of a hospital, starting from the feasibility phase or the early design stage. The framework involves different factors, such as the number of beds, complexity, typology, localization, technology degree and the type of maintenance and management techniques. This study explores the several elements that compose the cost of a hospital facility and highlights future developments including maintenance and management costs during hospital facilities’ lifecycle.

Sign in / Sign up

Export Citation Format

Share Document