Model Tests for the Validation of Extreme Roll Motion Predictions

2002 ◽  
Author(s):  
Walter L. Kuehnlein ◽  
K.-E. Brink
Keyword(s):  
Practical Knowledge ◽  
Rapid Development ◽  
Model Tests ◽  
Design Stage ◽  
Roll Motion ◽  
Ministry Of Education ◽  
Following Seas ◽  
Early Design Stage ◽  
Shaped Container ◽  
Motion Characteristics

At present common stability criteria are based on practical knowledge gained from the operation of ships. Therewith the assessment of ship safety against capsizing is partly determined by long-term statistics of accidents. Regulations like the IMO-Resolution A 167 do not rate the typical seakeeping characteristics of different hull form geometries. Therefore strictly speaking, these criteria are just applicable for ships of similar types as included in statistics. Rapid development in ship design calls for the determination of ship and cargo safety in regard of extreme roll motions or capsizing during early design stage. Within the ROLL-S project, which was founded by the German Federal Ministry of Education and Research, dynamic stability tests with a box shaped Container Ship and a RO-RO vessel have been performed. The performance of model tests, which are intended to serve for the validation of numerical simulation methods, put high demands on test and data acquisition techniques. The data of the waves encountered, course and position, as well as the response of the model had to be determined by model tests in order to use these data for the validation of numerical ship motion simulations. During the tests extreme roll motions of the two considered vessels could be observed in head seas and in following seas. Besides critical motion characteristics in following seas, like broaching, parametric induced roll motion effects were investigated in head sea condition. Remark: This paper should be read in conjunction with paper OMAE 2002-28297 which describes generation and transformation of the used waves.

Theoretical Investigation on Ice Resistance Prediction Methods for Ships in Level Ice

2014 ◽  
Author(s):  
Daniela Myland ◽  
Sören Ehlers
Keyword(s):  
Physical Nature ◽  
Model Tests ◽  
Design Stage ◽  
Prediction Methods ◽  
Sufficient Information ◽  
Early Design Stage ◽  
Level Ice ◽  
Resistance Prediction ◽  
Ship Performance ◽  
Ice Resistance

The assessment of the ship performance in ice covered waters has become more and more important in view of the increased interest in Arctic field logistics and transportation. The performance of ice-going or ice breaking ships is usually defined by their ability to proceed in uniform level ice, where good performance means low ice resistance, high propulsion efficiency and continuous ice breaking. In order to assess the ice breaking performance in an early design stage, model tests may be executed or several theoretical methods may be applied to predict the ice resistance may be applied. Due to the physical nature of model tests, all processes, i.e. forces contributing to ice resistance are considered. Thus, the execution of model tests is still the most reliable method to determine the ice resistance. But with regard to the high costs of model tests there is continued demand to gain knowledge on the reliability of theoretical prediction methods. The applicability of the method of choice depends on the underlying assumptions of the method itself and thus the method’s capability to predict and consider physical phenomena of interest. In this paper model tests are used to evaluate the influence of hull shape parameters and ice conditions on the breaking process, i.e. the ice resistance and the ship performance. Based on the knowledge gained a systematic comparison of existing, representative ice resistance prediction methods is carried out. The methods considered are state-of-the-art techniques which the original publications introduced with sufficient information to allow for their use in this comparison. It focuses on the suitability of the existing methods as engineering tools for the prediction of different components, as well as the total ice resistance itself. The incorporation of the ice resistance contributions in the different prediction methods is presented and differences are identified. On this basis an assessment of the assumptions and simplifications of these different numerical methods is outlined.

Maneuvering Predictions for Fast Monohulls in Early Design Stage

2015 ◽  
Author(s):  
F.H.H.A. Quadvlieg ◽  
F. van Walree ◽  
V. Barthelemy
Keyword(s):  
High Speed ◽  
Model Tests ◽  
Design Stage ◽  
Correct Prediction ◽  
Design Assessment ◽  
Early Design ◽  
Early Design Stage ◽  
Directional Stability ◽  
Pros And Cons ◽  
The Time Domain

The present paper discusses directional stability and course keeping of fast monohulls. Model tests and CFD were used for analysis. In itself these are great tools, but in early design stage they are often perceived as too elaborate. In comparison, design verification is often carried out during model testing., However, it is not common to use these model tests for systematic variation or multiple design variations. In addition to model tests, tools for early design assessment are also pursued. By using a 3D panel method, maneuvering coefficients and subsequently directional stability are found in an earlier stage of the design. The present paper describes which methods can be used in the design stage, and some pros and cons of these methods. A method of choice is selected and an example is elaborated. The example ship is a high speed monohull (Fn=0.8) propelled by waterjets. This paper illustrates that the forces acting on the ship while performing forced motions are predicted. A next step (not in the present paper) is to solve the equations of motions in the time domain as a system of ordinary differential equations. However, in order to correctly predict the motions and trajectories, the correct prediction of forces and moments is essential

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.

scholarly journals Multicore Early Design Stage Guaranteed Performance Estimates for the Space Domain

2019 ◽  
Author(s):  
Mikel Fernandez ◽  
Gabriel Fernandez ◽  
Jaume Abella ◽  
Francisco J. Cazorla
Keyword(s):  
Design Stage ◽  
Space Domain ◽  
Early Design ◽  
Early Design Stage ◽  
Performance Estimates

scholarly journals Macro-Modelling of Laser Micro-Joints for Understanding Joint Strength in Electric Vehicle Battery Interconnects

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3552
Author(s):  
Abhishek Das ◽  
Richard Beaumont ◽  
Iain Masters ◽  
Paul Haney
Keyword(s):  
Joint Strength ◽  
Structural Model ◽  
Design Stage ◽  
Structural Modelling ◽  
Laser Weld ◽  
Computationally Efficient ◽  
Early Design Stage ◽  
Lap Shear ◽  
Battery Module ◽  
Modelling Approach

Laser micro-welding is increasingly being used to produce electrically conductive joints within a battery module of an automotive battery pack. To understand the joint strength of these laser welds at an early design stage, micro-joints are required to be modelled. Additionally, structural modelling of the battery module along with the electrical interconnects is important for understanding the crash safety of electric vehicles. Fusion zone based micro-modelling of laser welding is not a suitable approach for structural modelling due to the computational inefficiency and the difficulty of integrating with the module model. Instead, a macro-model which computationally efficient and easy to integrate with the structural model can be useful to replicate the behaviour of the laser weld. A macro-modelling approach was adopted in this paper to model the mechanical behaviour of laser micro-weld. The simulations were based on 5 mm diameter circular laser weld and developed from the experimental data for both the lap shear and T-peel tests. This modelling approach was extended to obtain the joint strengths for 3 mm diameter circular seams, 5 mm and 10 mm linear seams. The predicted load–displacement curves showed a close agreement with the test data.

A Performance Modeling Language for Automotive Embedded Control Systems Based on UML

2012 ◽  
Vol 236-237 ◽  
pp. 344-349
Author(s):  
Xiao Feng Yin ◽  
Jing Xing Tan ◽  
Xiu Ting Wu ◽  
Zhi Jun Gong
Keyword(s):  
Performance Modeling ◽  
Resource Constraints ◽  
Timing Analysis ◽  
Unified Modeling Language ◽  
Functional Model ◽  
Design Stage ◽  
Modeling Language ◽  
Embedded Control ◽  
Early Design Stage ◽  
A Performance

To improve the timing related performance of the embedded software of automotive control system, a performance modeling language has been developed based on UML (Unified Modeling Language) using meta-modeling technique. The proposed language consists of three kinds of meta-models used to define the high-level modeling paradigms for software structure, target platform and runtime system respectively. The modeling environment configured by the proposed language and software modules of functional model importation, components allocation, task forming and timing analysis can reuse the existing functional models, add timing requirement as well as resource constraints, and fulfill formal timing analysis at an early design stage. As results, the reliability of the automotive embedded control software can be improved and the development cycle and cost can also be reduced.

A hybrid metamodel-based method for quick energy prediction in the early design stage

2021 ◽  
pp. 128825
Author(s):  
Shuyan Zhu ◽  
Yufeng Zhang ◽  
Ke Xiang ◽  
Chenlong Ma
Keyword(s):  
Design Stage ◽  
Early Design ◽  
Energy Prediction ◽  
Early Design Stage

QSHIP; Advanced Use of Hydromechanics in Early Design Stage

2009 ◽  
Author(s):  
A Bons ◽  
Keyword(s):  
Design Stage ◽  
Early Design ◽  
Early Design Stage

A Dynamic Analysis Of The Impact Of Air Pollution On The daylight Availability In An Open-plan Office In London

2021 ◽  
pp. 94-103
Author(s):  
Jiangtao Du ◽  
Steve Sharples
Keyword(s):  
Air Pollution ◽  
Urban Areas ◽  
Simulation Analysis ◽  
Design Stage ◽  
Design Strategies ◽  
Early Design Stage ◽  
Pollutant Deposition ◽  
Open Plan ◽  
Building Project ◽  
The Impact

The deposition of air pollutants on glazing can significantly affect the daylight transmittance of building fenestration systems in urban areas. This study presents a simulation analysis of the impact of air pollution and glazing visual transmittance on indoor daylight availability in an open-plan office in London. First, the direct links between glazing visual transmittance and daylighting conditions were developed and assessed. Second, several simple algorithms were established to estimate the loss of daylight availability due to the pollutant deposition at the external surface of vertical glazing. Finally, some conclusions and design strategies to support facade planning at the early design stage of an urban building project were developed.

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