A Consideration on the Dynamic Behavior and the Structural Design of Large Scale Floating Structure

Collisions and grounding accidents of ships, but also the failure of the hull-integrity, can lead to oil leakage. Examples are the Rena in 2011, the Hebei Spirit in 2007 and the much known accident of the Prestige in 2002. Consequently research regarding the enhancement of the structural design to increase the safety-level of ships in case of accidents is important. In this paper the use of a rubber bag as a second barrier is presented as an alternative concept to prevent oil leakage in case of accidents. The influence of the rubber bag is investigated using the example of a ship collision. A simplified tanker side structure as well as a box shaped rubber bag are analyzed with the finite element method. The material model for the rubber bag is calibrated with tensile tests to obtain the required material parameters. The reaction forces and the associated penetration depth are analyzed. The comparison is done between the structure with and without the rubber bag. For the latter, the general behavior is compared with large-scale experimental results. Furthermore an additional increase of the survivability of the ship due to the rubber bag without changing the common structural design is discussed.

Download Full-text

Large-Scale Structural Design Optimization

Large-Scale Optimization with Applications - The IMA Volumes in Mathematics and its Applications ◽

10.1007/978-1-4612-1960-6_10 ◽

1997 ◽

pp. 235-245

Author(s):

Ulf Torbjörn Ringertz

Keyword(s):

Design Optimization ◽

Structural Design ◽

Large Scale ◽

Structural Design Optimization

Download Full-text

Design of Huge Complex Building of Two Structurally Independent Seismic Isolation Structures Coupled by Unique Expansion Joint

IABSE Congress, New York, New York 2019: The Evolving Metropolis ◽

10.2749/newyork.2019.1681 ◽

2019 ◽

Author(s):

Masaru Kokonno ◽

Tatsuhiko Maeda ◽

Keita Tahara ◽

Marina Kouda ◽

Yoshiaki Sawai ◽

...

Keyword(s):

Economic Efficiency ◽

Structural Design ◽

Seismic Isolation ◽

Large Scale ◽

Building Codes ◽

Expansion Joint ◽

Long Period ◽

Complex Building

For large‐scale complex facilities, the authors designed seismic isolation structures which were ensured the highest‐level safety in a rational and economic way.We split the building into two first, and then planned the buildings so that their spans and story heights might be optimum according to their uses, and performed the structural design of each building in pursuit of rationality and economic efficiency as well as safety. Finally, the buildings were integrated into one by connecting the two seismic isolation buildings with special expansion joint which was developed for these buildings.Additionally, we considered long‐period earthquakes and strong inland earthquakes that were larger than the reference earthquake of the Japanese Building Codes to ensure highest‐level aseismic performance.

Download Full-text

Fundamental Study on Elastic Behavior of Large-Scale Floating Coal Stockyard

Volume 6: Ocean Space Utilization; Ocean Renewable Energy ◽

10.1115/omae2016-54958 ◽

2016 ◽

Author(s):

Hiroaki Eto ◽

Chiaki Sato ◽

Koichi Masuda ◽

Tomoki Ikoma ◽

Tomoyuki Kishida ◽

...

Keyword(s):

Mass Distribution ◽

Large Scale ◽

Asia Pacific ◽

Elastic Behavior ◽

Loading Conditions ◽

Floating Structure ◽

Fundamental Study ◽

Local Rigidity ◽

East Kalimantan ◽

The Impact

This paper proposes a large-scale floating coal stockyard (LFCS) and discusses its elastic behavior. Indonesia has recently become the main country supplying coal in the Asia-Pacific region. However, there is concern that export to Japan will decrease as coal demand increases. Therefore, the trend of coal transport in Indonesia is a very important matter in ensuring the continued stable import of coal to Japan. It is difficult for bulk carriers to traverse the shallow terrain of the seabed of the Markham River in East Kalimantan to reach coastal areas. Additionally, an LFCS can be operated as a relay base for barges, and large coal carriers have been proposed for use in offshore areas. The LFCS is capable of loading, storing, and offloading coal. Installing an LFCS offshore Kalimantan is expected to improve coal transport productivity in the region. Under such circumstances, the design plan proposed in this paper can simultaneously perform independent loading and unloading without interference. The partial mass distribution and local rigidity of the LFCS varies depending on the coal loading conditions. In addition, because the structure has a planar shape, the response of the LFCS showed elastic behavior. Design example of such a huge floating structure with the great difference of the displacement is unparalleled, it is very important to clarify a design fundamental subject. The objectives of this study are to provide a preliminary LFCS design and investigate the impact of varying the mass distribution and local rigidity on not only the distribution of the distortion and internal stress but also on the dynamic hydroelastic motion of the LFCS when it is impacted by waves. Therefore, the wave response of the LFCS was analyzed under different loading conditions.

Download Full-text

Dynamic Behavior of a Novel Heave-Compensated Floating Platform for Well Interventions

Volume 11: Petroleum Technology ◽

10.1115/omae2020-18472 ◽

2020 ◽

Author(s):

Marcelo A. Jaculli ◽

Bernt J. Leira ◽

Sigbjørn Sangesland ◽

Celso K. Morooka ◽

José Ricardo P. Mendes

Keyword(s):

Dynamic Behavior ◽

Small Diameter ◽

Floating Platform ◽

Floating Structure ◽

Cross Sectional ◽

Platform Design ◽

The North ◽

The North Sea ◽

Heave Motion ◽

Intervention Costs

Abstract A new type of floating platform design has been investigated. It consists of a relatively small semi-submersible floating structure with an air chamber that aims to keep a constant buoyancy, thus effectively reducing heave motion and enabling its use under harsh environmental conditions such as in the North Sea. It aims to provide an alternative solution compared to large floating structures, such as drillships and semi-submersible platforms, in terms of time availability, drilling costs and operational flexibility. One recent focus has been on the application of this platform for reducing well intervention costs. A small diameter (workover) riser may be used for installing the well control stack on the wet Christmas tree and for performing well intervention through the riser using a wireline cable. Alternatively, the operation can take place without a riser; this operation is termed riserless well intervention (RLWI). In this work, we investigate the dynamic behavior of this system, which is attached either to a wireline — for RLWI — or to a small-sized riser for well service through the riser. By modeling this system — which acts similarly to a passive heave compensation system — we have verified that this new platform indeed experiences smaller displacements when compared to conventional platform. The reduction observed varies depending on the platform design; in some cases, it reduces the displacement by a factor of two. A relatively heavier platform with a small cross sectional water plane area is found to be the best design option, but a lighter platform might be preferable for increased flexibility, as long as its dynamic behavior is satisfactory for safe operations.

Download Full-text

ANALYZING DYNAMIC BEHAVIOR OF LARGE-SCALE SYSTEMS THROUGH MODEL TRANSFORMATION

International Journal of Software Engineering and Knowledge Engineering ◽

10.1142/s0218194005001896 ◽

2005 ◽

Vol 15 (01) ◽

pp. 35-60 ◽

Cited By ~ 3

Author(s):

MICHAEL E. SHIN ◽

ALEXANDER H. LEVIS ◽

LEE W. WAGENHALS ◽

DAE-SIK KIM

Keyword(s):

Dynamic Behavior ◽

Model Transformation ◽

Large Scale ◽

System Model ◽

Use Case ◽

Class Model ◽

Large Scale Systems ◽

Collaboration Model ◽

Model Class ◽

Use Case Model

This paper describes model transformation for analyzing dynamic behavior of large-scale systems. The Unified Modeling Language (UML) based system model is transformed into the Colored Petri Nets (CPN) model, which is used for analyzing the scenarios of the use cases of a system and checking freedom of system deadlock at an early stage of software development. The CPN model that is executable is hierarchically structured on the basis of the functional decomposition of a large-scale system. The UML-based system model consisting of the use case model, class model and collaboration model is not executable so that the dynamic behavior of the system cannot be analyzed until implementation of the system. However, the UML-based system model has no hierarchical structure to be transformed into the hierarchical CPN model as well. The discrepancies of dynamic and structural views in the two models are resolved by transformation of the UML model into the layered, executable CPN model with three layers — the use case layer, object layer and operation layer. The model transformation is carried out using relationships among the use case model, class model, and collaboration model of the UML. With the executable CPN model transformed, the dynamic properties of the system are analyzed using the simulation technique, occurrence graph, and state space report provided by the Design/CPN tool. The approach in this paper is validated through two case studies — the gas station system and the distributed factory automation system.

Download Full-text