Design Through Simulation: Finite Element Capabilities for Ocean Engineering

2008 ◽  
Author(s):  
Dean M. Steinke ◽  
Ryan S. Nicoll ◽  
Bradley J. Buckham
Keyword(s):  
Finite Element ◽  
Design Optimization ◽  
Early Stage ◽  
Offshore Structures ◽  
Cable Model ◽  
Ocean Engineering ◽  
Remotely Operated Vehicle ◽  
Mooring Lines ◽  
Nonlinear Simulation ◽  
Early Stage Design

Design optimization and testing of marine technology and offshore structures, such as risers, moorings, or manned and unmanned submersibles is a challenge. This is due to many factors including weather, costly ship time, and the need for experienced off-shore personnel. Nevertheless, early stage design optimization is critical to a project’s success. There is a need for simulation facilities that can capture the complexity and the non-linear dynamics of large mechanical and structural systems, and provide accurate assessment of design variations. This article outlines the development of a nonlinear simulation tool for modeling mechanical systems and structures in the ocean. The framework design and simulation set-up procedures are discussed. The main components of the simulator, a nonlinear finite element cable model and a rigid body model, are discussed. Next, this paper shows how these fundamental models are used to simulate risers, remotely operated vehicle (ROV) umbilicals, and mooring lines. In addition, a module that produces the effects of vortex induced vibration (VIV) based on recent developments on the wake oscillator model is presented. Payin and payout simulations of a ROV tether are also presented to demonstrate the use of the variable-length capabilities of the cable model. Lastly, this paper discusses how ROV instrumentation can be simulated, permitting the design and refinement of instrumentation processing algorithms, such as a Kalman filter, or controllers.

Selecting a Compressor Meridional Topology: Axial, Mixed, Radial

2021 ◽  
Author(s):  
Jonathan M. Smyth ◽  
Robert J. Miller
Keyword(s):  
Design Optimization ◽  
Early Stage ◽  
New Products ◽  
Systems Design ◽  
Blade Design ◽  
Improved Method ◽  
Stage Design ◽  
Specific Speed ◽  
Early Stage Design ◽  
Smith Chart

Abstract This paper proposes a new duty-based Smith Chart as part of an improved method of selecting the geometric topology of compressors (axial, mixed or radial) in the earliest stage of design. The method has a number of advantages over previous methods: it is based on the non-dimensional flow and the non-dimensional work, which aligns with the aerodynamic function of the compressor and is therefore more intuitive than specific speed and specific diameter. It is based on a large number of consistently designed compressor rotors which have been computationally predicted using RANS CFD. Most importantly, it provides the designer not only with a choice of topology but also with the complete meridional geometry of the compressor, its blade design and the number of blades. This fidelity of geometry at the very early stage of design allows the designer to undertake a true systems design optimization (noise, manufacturing, packaging constraints and cost). This has the major advantage of significantly reducing early stage design times and costs and allows the designer to explore completely new products more quickly.

scholarly journals Design and fabrication of a twist fixture to measure torsional stiffness of a pick up chassis

2018 ◽  
Vol 159 ◽  
pp. 02030 ◽  
Author(s):  
Ojo Kurdi ◽  
Mohd Shukri Yob ◽  
Awisqarni Haji Ishamuddin ◽  
Agus Suprihanto ◽  
Susilo Adi Widyanto ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Early Stage ◽  
Torsional Stiffness ◽  
Stage Design ◽  
Handling Performance ◽  
Simulation Results ◽  
Early Stage Design ◽  
Measured Displacement ◽  
Dial Indicator

Torsional stiffness is important parameter of chassis that affect the handling performance of chassis. Torsional stiffness can be determined using Finite Element Method (FEM) in early stage design of its. In order to validate the FEM result, experimental work needs to be done. The fixture has been design in simpler stucture, flexible for any kind of chassis and using a simple measurement’s equipment such as dial indicator and load cell. Twist fixture has been designed for measuring of torsional stiffness of TATA cab chassis indirectly. The fixture measured the deflection caused by torsion subjected to the chassis. The torsional stiffness was calculated based on measured displacement of chassis. The result of comparison shows that the experimental results in agreement with the simulation results. Therefore, the simulation results of TATA cab chassis model are valid.

Influence of Nonlinear Mooring Stiffness on Hydrodynamic Performance of Floating Bodies

2009 ◽  
Author(s):  
Huilong Ren ◽  
Jian Zhang ◽  
Guoqing Feng ◽  
Hui Li ◽  
Chenfeng Li
Keyword(s):  
Equilibrium Position ◽  
Equations Of Motion ◽  
Offshore Structures ◽  
Hydrodynamic Performance ◽  
Coupled Analysis ◽  
Mooring System ◽  
Main Function ◽  
Ocean Engineering ◽  
Mooring Lines ◽  
Floating Structures

Coupled dynamic analysis between floating marine structures and flexible members such as mooring lines and risers, is a challenging work in the ocean engineering field. Coupled analysis on mooring-buoy interactions has been paid more and more concern for recent years. For floating offshore structures at sea, the motions driven by environmental loads are inevitable. The movement of mooring lines occurs due to the excitation on the top by floating structures. Meanwhile the lines restrict the buoy’s motion by forces acting on the fareleads. Positioning is the main function of mooring system, its orientation effects can’t be ignored for floating structures such as semi-submersible, FPS, and TLP, especially when the buoy’s equilibrium position shifting to another place. Similar as hydrostatic restoring forces, mooring force related with the buoy’s displacement can be transformed into mooring stiffness and can be added in the differential equations of motion, which is calculated at its equilibrium point. For linear hydrodynamic analysis in frequency domain, any physical quantity should be linear or be linearized, however mooring stiffness is nonlinear in essence, so the tangent or differential stiffness is used. Steel chains are widely used in catenary mooring system. An explicit formulation of catenary mooring stiffness is derived in this article, which consists of coupled relations between horizontal and vertical mooring forces. The effects of changing stiffness due to the shift of equilibrium position on the buoy’s hydrodynamic performance are investigated.

scholarly journals A DISCRETE-EVENT SIMULATION MODEL FOR DRIVER PERFORMANCE ASSESSMENT: APPLICATION TO AUTONOMOUS VEHICLE COCKPIT DESIGN OPTIMIZATION

2020 ◽  
Vol 1 ◽  
pp. 2521-2530
Author(s):  
I. Iuskevich ◽  
A. M. Hein ◽  
K. Amokrane-Ferka ◽  
A. Doufene ◽  
M. Jankovic
Keyword(s):  
Design Optimization ◽  
Discrete Event Simulation ◽  
Situation Awareness ◽  
Early Stage ◽  
Autonomous Vehicle ◽  
Discrete Event ◽  
Event Simulation ◽  
Architecture Evaluation ◽  
Early Stage Design ◽  
Cockpit Design

AbstractThe latest advances in the design of vehicles with the adaptive level of automation pose new challenges in the vehicle-driver interaction. Safety requirements underline the need to explore optimal cockpit architectures with regard to driver cognitive and perceptual workload, eyes-off-the-road time and situation awareness. We propose to integrate existing task analysis approaches into system architecture evaluation for the early-stage design optimization. We built the discrete-event simulation tool and applied it within the multi-sensory (sight, sound, touch) cockpit design industrial project.

Evaluation of Loads During a Free-Fall Lifeboat Drop

2013 ◽  
Author(s):  
Andrea Califano ◽  
Kristoffer Brinchmann
Keyword(s):  
Finite Element ◽  
Structural Integrity ◽  
Early Stage ◽  
Free Fall ◽  
Element Model ◽  
Emergency Evacuation ◽  
Offshore Structures ◽  
Element Analysis ◽  
Safety Requirements ◽  
Structural Capacity

A new Offshore Standard (DNV-OS-E406) [1] has been developed for the design of Free Fall Lifeboats (FFLB) used for emergency evacuation from offshore structures. This standard aims at ensuring safe evacuation, focusing on the design at an early stage. Load (CFD) and structural (FE) analyses are used to assist in determining whether or not the free fall lifeboats comply with the Target Safety requirements as set forth by the Standard. The present paper describes the methodology used when assessing the structural capacity of FFLB. The structural integrity is established throughout every phase of a lifeboat drop, linking computational fluid dynamics (CFD) and finite element analysis (FEA). Loads computed from CFD on a finite volume mesh are interpolated to a finite element model where the structural analysis can be performed in order to obtain stresses, strains and deflections, and finally assess the structural capacity of the lifeboat. Emphasis in this work is given to the hydrodynamic model and loads, while structural analyses are discussed more in depth by Brinchmann et al. [2].

scholarly journals Effect of Roughness of Mussels on Cylinder Forces from a Realistic Shape Modelling

2021 ◽  
Vol 9 (6) ◽  
pp. 598
Author(s):  
Antoine Marty ◽  
Franck Schoefs ◽  
Thomas Soulard ◽  
Christian Berhault ◽  
Jean-Valery Facq ◽  
...  
Keyword(s):  
Marine Species ◽  
Offshore Structures ◽  
Offshore Wind ◽  
Mooring Lines ◽  
Shape Modelling ◽  
Offshore Wind Turbines ◽  
Specific Effects ◽  
Hydrodynamic Loading ◽  
Floating Offshore Wind Turbines ◽  
Realistic Shape

After a few weeks, underwater components of offshore structures are colonized by marine species and after few years this marine growth can be significant. It has been shown that it affects the hydrodynamic loading of cylinder components such as legs and braces for jackets, risers and mooring lines for floating units. Over a decade, the development of Floating Offshore Wind Turbines highlighted specific effects due to the smaller size of their components. The effect of the roughness of hard marine growth on cylinders with smaller diameter increased and the shape should be representative of a real pattern. This paper first describes the two realistic shapes of a mature colonization by mussels and then presents the tests of these roughnesses in a hydrodynamic tank where three conditions are analyzed: current, wave and current with wave. Results are compared to the literature with a similar roughness and other shapes. The results highlight the fact that, for these realistic roughnesses, the behavior of the rough cylinders is mainly governed by the flow and not by their motions.

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