Maneuvering Model for FPSOs and Stability Analysis of the Offloading Operation

2002 ◽  
Vol 124 (4) ◽  
pp. 196-202 ◽  
Author(s):  
Sergio H. Sphaier ◽  
Antonio C. Fernandes ◽  
Sylvio H. S. Correa ◽  
Gustavo A. V. Castro
Keyword(s):  
Mathematical Model ◽  
Stability Analysis ◽  
Classical Theory ◽  
Deep Water ◽  
Experimental Test ◽  
Dynamic Systems ◽  
Scale Effects ◽  
Local Analysis ◽  
Floating System ◽  
The Stability

The discovery of new fields in deep water brought back the use of large ships such as FPSOs. This seems to be the trend toward ultra deep water units at least in offshore Brazil. At about the same time, VLCCs (very large crude carriers) have been converted to work as FPSOs. However, working as a stationary unit a VLCC presents directional stability problems. In the present paper a methodology is discussed to develop a mathematical model for the simulation and the verification of the stability of a VLCC working as a FPSO. To express the forces and moments acting on the ship hull the results of a group of experiments are described in the classical sense of the maneuverability theory, although they concern large angles of attack and low advance velocity. Besides, a procedure to determine the stability of the floating system is also presented. This is based on local analysis and follows the classical theory of dynamic systems. Further, the use of stabilization devices for a floating unit and the offloading operation are discussed. Finally, an experimental test is proposed, in order to take into account scale effects.

Walking Stability Analysis of Multi-Legged Crablike Robot over Slope

2013 ◽  
Vol 572 ◽  
pp. 636-639
Author(s):  
Xi Chen ◽  
Gang Wang
Keyword(s):  
Mathematical Model ◽  
Stability Analysis ◽  
Stability Criterion ◽  
Stability Margin ◽  
Static Stability ◽  
Matlab Simulation ◽  
And Performance ◽  
The Stability ◽  
The Mathematical Model ◽  
The Relationship

This paper deals with the walking stability analysis of a multi-legged crablike robot over slope using normalized energy stability margin (NESM) method in order to develop a common stabilization description method and achieve robust locomotion for the robot over rough terrains. The robot is simplified with its static stability being described by NESM. The mathematical model of static stability margin is built so as to carry out the simulation of walking stability over slope for the crablike robot that walks in double tetrapod gait. As a consequence, the relationship between stability margin and the height of the robots centroid, as well as its inclination relative to the ground is calculated by the stability criterion. The success and performance of the stability criterion proposed is verified through MATLAB simulation and real-world experiments using multi-legged crablike robot.

Dynamic Stability of FPSO-Shuttle Systems: An Analytical Procedure and Practical Results

2002 ◽  
Author(s):  
Ge´rson B. Matter ◽  
Joel S. Sales ◽  
Sergio H. Sphaier
Keyword(s):  
Dynamic Stability ◽  
Deep Water ◽  
Dynamic Systems ◽  
Time Domain ◽  
Equilibrium Position ◽  
Analytical Procedure ◽  
Time Domain Analysis ◽  
The Stability ◽  
The Time Domain ◽  
Floating Systems

The paper deals with the dynamics of floating systems (FPSO units) moored in deep water in the presence of currents. The offloading operation is carried out in a tandem arrangement from the FPSO to a Shuttle ship of lesser capacity. According to the classical theory of dynamic systems, a study of the behavior of floating units is performed by determining the equilibrium position and then analyzing the stability around this position. The time domain analysis is also used to compare the results. This procedure is extended to the case of systems in a spread mooring configuration and with turret.

Influence of Nonlinearities on the Behavior of Parametrically Excited Articulated Pipes Conveying Fluid

1978 ◽  
Vol 5 (1) ◽  
pp. 31-38 ◽  
Author(s):  
J. Rousselet ◽  
G. Herrmann
Keyword(s):  
Fluid Flow ◽  
Stability Analysis ◽  
Dynamic Systems ◽  
Linear Formulation ◽  
Fluctuating Pressure ◽  
The Past ◽  
Pipes Conveying Fluid ◽  
Critical Velocities ◽  
The Stability ◽  
Conveying Fluid

This paper presents the analysis of a system of articulated pipes hanging vertically under the influence of gravity. The liquid, driven by a slightly fluctuating pressure, circulates through the pipes. Similar systems have been analysed in the past by numerous authors but a common feature of their work is that the behavior of the fluid flow is prescribed, rather than left to be determined by the laws of motion. This leads to a linear formulation of the problem which can not predict the behavior of the system for finite amplitudes of motion. A circumstance in which this behavior is important arises in the stability analysis of the system in the neighbourhood of critical velocities, that is, flow velocities at which the system starts to flutter. Hence, the purpose of the present study was to investigate in greater detail the region close to critical velocities in order to find by how much these critical velocities would be affected by the amplitudes of motion. This led to a set of three coupled-nonlinear equations, one of which represents the motion of the fluid. In the mathematical development, use is made of a scheme which permits the uncoupling of the modes of motion of damped nonconservative dynamic systems. Results are presented showing the importance of the nonlinearities considered.

scholarly journals Dynamics in Bank Crisis Model

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Tianshu Jiang ◽  
Mengzhe Zhou ◽  
Bi Shen ◽  
Wendi Xuan ◽  
Sijie Wen ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Complex Networks ◽  
Critical Point ◽  
Dynamic Systems ◽  
Degree Distribution ◽  
Equilibrium Points ◽  
Modified Model ◽  
The Past ◽  
Banking Market ◽  
The Stability

Bank crisis is grabbing more serious attention as several financial turmoils have broken out in the past several decades, which leads to a number of researches in this field. Comparing with researches carried out on basis of degree distribution in complex networks, this paper puts forward a mathematical model constructed upon dynamic systems, for which we mainly focus on the stability of critical point. After the model is constructed to describe the evolution of the banking market system, we devoted ourselves to find out the critical point and analyze its stability. However, to refine the stability of the critical point, we add some impulsive terms in the former model. And we discover that the bank crisis can be controlled according to the analysis of equilibrium points of the modified model, which implies the interference from outside may modify the robustness of the bank network.

Modeling and Stability Analysis of Hydraulic System for Wave Simulation

2013 ◽  
Vol 291-294 ◽  
pp. 1934-1939
Author(s):  
Jian Jun Peng ◽  
Yan Jun Liu ◽  
Yu Li ◽  
Ji Bin Liu
Keyword(s):  
Mathematical Model ◽  
Stability Analysis ◽  
Mathematical Models ◽  
Hydraulic System ◽  
Simulation System ◽  
Displacement Sensor ◽  
Schematic Diagram ◽  
Wave Simulation ◽  
The Stability ◽  
The Mathematical Model

This thesis put forward a hydraulic wave simulation system based on valve-controlled cylinder hydraulic system, which simulated wave movement on the land. The mathematical model of valve-controlled symmetric cylinder was deduced and the mathematical models of servo valve, displacement sensor and servo amplifier were established according to the schematic diagram of the hydraulic system designed, on the basis of which the mathematical model of hydraulic wave simulation system was obtained. Then the stability of the system was analyzed. The results indicated that the system was reliable.

A Generalized Hill’s Method for the Stability Analysis of Parametrically Excited Dynamic Systems

1982 ◽  
Vol 49 (1) ◽  
pp. 217-223 ◽  
Author(s):  
S. T. Noah ◽  
G. R. Hopkins
Keyword(s):  
Stability Analysis ◽  
Dynamic Systems ◽  
Absolute Convergence ◽  
General System ◽  
Closed Form Expression ◽  
Form Expression ◽  
Null Solution ◽  
Hill’S Method ◽  
The Stability ◽  
Pulsating Fluid

A method is described for investigating the stability of the null solution for a general system of linear second-order differential equations with periodic coefficients. The method is based on a generalization of Hill’s analysis and leads to a generalized Hill’s infinite determinant. Following a proof of its absolute convergence, a closed-form expression for the characteristic infinite determinant is obtained. Methods for the stability analysis utilizing different forms of the characteristic determinant are discussed. For cases where the instabilities are of the simple parametric type, a truncated form of the determinant may be used directly to locate the boundaries of the resonance regions in terms of appropriate system parameters. The present generalized Hill’s method is applied to a multidegree-of-freedom discretized system describing pipes conveying pulsating fluid. It is demonstrated that the method is a flexible and efficient computational tool for the stability analysis of general periodic systems.

scholarly journals A Mathematical Model of the Transition from the Normal Hematopoiesis to the Chronic and Accelerated Acute Stages in Myeloid Leukemia

2020 ◽  
Author(s):  
Lorand Gabriel Parajdi ◽  
Radu Precup ◽  
Eduard Alexandru Bonci ◽  
Ciprian Tomuleasa
Keyword(s):  
Mathematical Model ◽  
Stem Cells ◽  
Bone Marrow ◽  
Stability Analysis ◽  
Myeloid Leukemia ◽  
Transition Process ◽  
Two Dimensional ◽  
The Stability ◽  
Theoretical Results

A mathematical model given by a two - dimensional differential system is introduced in order to understand the transition process from the normal hematopoiesis to the chronic and accelerated acute stages in chronic myeloid leukemia. A previous model of Dingli and Michor is refined by introducing a new parameter in order to differentiate the bone marrow microenvironment sensitivities of normal and mutant stem cells. In the light of the new parameter, the system now has three distinct equilibria corresponding to the normal hematopoietic state, to the chronic state, and to the accelerated acute phase of the disease. A characterization of the three hematopoietic states is obtained based on the stability analysis. Numerical simulations are included to illustrate the theoretical results.

scholarly journals Instability of Liquid-Film Flows With Temperature-Dependent properties Down A Heated Incline

2021 ◽  
Author(s):  
Syeda Rubaida Zafar
Keyword(s):  
Mathematical Model ◽  
Free Surface ◽  
Stability Analysis ◽  
Marangoni Effect ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Temperature Dependent ◽  
The Stability ◽  
Temperature Dependent Properties ◽  
Film Flows

In this thesis we investigate the stability of free-surface flow on a heated incline. We develop a complete mathematical model for the flow which captures the Marangoni effect and also accounts for changes in the properties of the fluid with temperature. We apply a linear stability analysis to determine the stability of the steady and uniform flow. The associated eigenvalue problem is solved numerically by means of a spectral colocation method.

Concept Of The Decomposition And Aggregation Method With Example: Part 1

1988 ◽  
pp. 27-40
Author(s):  
Dr. Zainol Anuar Mohd. Sharif ◽  
Ng Boon Choong
Keyword(s):  
Stability Analysis ◽  
Dynamic Systems ◽  
Basic Concept ◽  
Large Scale ◽  
Direct Method ◽  
Aggregation Method ◽  
Control Engineering ◽  
Large Scale Systems ◽  
Engineering Economics ◽  
The Stability

This paper describes the basic concept of the decomposition and aggregation method. It shows the feasibility of the method and its advantages when applied, particularly to large scale systems. This method is extensively used in solving problems related to control engineering, economics, optimization and stability. This paper also illustrates specifically the application of the method of decomposition and aggregation in the analysis of dynamic systems. It is divided into two important parts, namely; the decomposition part which involves breaking up a large system into subsystems and the aggregation part which is obtained through a reformulation of the Liapunov's second method (direct method). The relation between the decomposition and the aggregation methods is also shown. The procedure for checking the stability based on this concept is also outlined.For further illustration, an example of a dynamic system has been included. It shows how the system is decomposed and aggregated to suit the requirement for stability analysis.

CONVENTIONAL MODELLING APPROACH TO PREDICT THE DYNAMICS OF COVID-19

2021 ◽  
Vol 5 (2) ◽  
pp. 470-476
Author(s):  
S Bashir ◽  
I. Z. Shehu ◽  
N. Chinenye
Keyword(s):  
Mathematical Model ◽  
Stability Analysis ◽  
Basic Reproduction Number ◽  
Reproduction Number ◽  
Transmission Dynamics ◽  
The Stability ◽  
Modelling Approach

The study examined transmission dynamics of COVID-19 with conventional modelling approach. We developed a mathematical model for COVID-19 pandemic as SEQIR where I, the infected compartment is partitioned in to  and for reported and unreported group of infected individuals. Basic reproduction number has been obtained and the stability analysis was carried out. The results revealed that the disease may die out in time

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