Simulation Based Estimation of Extreme Response of Floating Offshore Structures

2007 ◽  
Author(s):  
A. Naess ◽  
O. Gaidai ◽  
P. S. Teigen
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Saddle Point ◽  
Computation Time ◽  
Offshore Structures ◽  
Saddle Point Method ◽  
Response Level ◽  
Random Seas ◽  
The Monte Carlo Method ◽  
Extreme Response

The paper presents a study of the extreme response statistics of a tension leg platform (TLP) subjected to random seas. Two different approaches are compared: A numerical integration method based on saddle point integration and the Monte Carlo method. While the saddle point method is a mathematically attractive technique, which gives numerically very accurate results at low computational costs at any response level, the advantage of the Monte Carlo method is its simplicity and versatility. It is demonstrated in this paper that the commonly assumed obstacle against using the Monte Carlo method for estimating extreme responses, i.e. excessive CPU time, can be circumvented, bringing the computation time down to affordable levels. The agreement between the two approaches is shown to be remarkably good.

A Monte Carlo Approach to Prediction of Extreme Response Statistics of Drag Dominated Offshore Structures

2007 ◽  
Author(s):  
A. Naess ◽  
O. Gaidai
Keyword(s):  
Monte Carlo ◽  
Weather Conditions ◽  
Offshore Structures ◽  
Drag Forces ◽  
Wave Elevation ◽  
The Monte Carlo Method ◽  
Strong Current ◽  
Highly Nonlinear ◽  
Extreme Response

The focus of the present paper is the extreme response statistics of drag dominated offshore structures subjected to harsh weather conditions. More specifically, severe sea states both with and without strong current are considered. The nature of the hydrodynamic forces acting on the structure becomes highly nonlinear. Additionally to the drag forces, the so called inundation effect due to the wave elevation, corrected to include second order waves, is also taken into account. In the present paper the Monte Carlo method along with a special extrapolation technique is applied. The proposed method opens up the possibility to predict simply and efficiently long-term extreme response statistics, which is an important issue for the offshore structures design.

Equation Solving DRESOR Method for Radiative Transfer in Three-Dimensional Isotropically Scattering Media

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Zhifeng Huang ◽  
Huaichun Zhou ◽  
Guihua Wang ◽  
Pei-feng Hsu
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Computation Time ◽  
Discrete Ordinates ◽  
Distinct Advantage ◽  
Reverse Monte Carlo ◽  
Scattering Media ◽  
Equation Solving ◽  
Radiative Intensity ◽  
The Monte Carlo Method

Distributions of ratios of energy scattered or reflected (DRESOR) method is a very efficient tool used to calculate radiative intensity with high directional resolution, which is very useful for inverse analysis. The method is based on the Monte Carlo (MC) method and it can solve radiative problems of great complexity. Unfortunately, it suffers from the drawbacks of the Monte Carlo method, which are large computation time and unavoidable statistical errors. In this work, an equation solving method is applied to calculate DRESOR values instead of using the Monte Carlo sampling in the DRESOR method. The equation solving method obtains very accurate results in much shorter computation time than when using the Monte Carlo method. Radiative intensity with high directional resolution calculated by these two kinds of DRESOR method is compared with that of the reverse Monte Carlo (RMC) method. The equation solving DRESOR (ES-DRESOR) method has better accuracy and much better time efficiency than the Monte Carlo based DRESOR (original DRESOR) method. The ES-DRESOR method shows a distinct advantage for calculating radiative intensity with high directional resolution compared with the reverse Monte Carlo method and the discrete ordinates method (DOM). Heat flux comparisons are also given and the ES-DRESOR method shows very good accuracy.

Extreme Response Statistics of Fixed Offshore Structures Subjected to Ringing Loads

2009 ◽  
Author(s):  
Oleg Gaidai ◽  
Jo̸rgen Krokstad
Keyword(s):  
Monte Carlo ◽  
Structural Response ◽  
Offshore Structures ◽  
Statistical Technique ◽  
Computational Effort ◽  
Contour Method ◽  
Wave Impact ◽  
Random Seas ◽  
Extreme Response ◽  
Time Histories

Paper describes a method for prediction of extreme response statistics of fixed offshore structures subjected to random seas by Monte Carlo simulation. The nonlinear structural response know as “ringing” is studied, caused by the wave impact force on structural support units. Common challenge for design of such structures is a sound estimate of the hydrodynamic load inclusive diffraction effects. Structure is modeled as a multi-degree of freedom (MDOF) system and number of Monte Carlo simulations was performed to highlight extreme response in severe random seas. Since MDOF numerical simulation is costly, an efficient statistical technique was adopted, minimizing required computational effort. Environmental contour method was combined with accurate distribution tail extrapolation. The aim of the work was to develop specific methods which make it possible to extract the necessary information about the extreme response from relatively short time histories. The method proposed in this paper opens up the possibility to predict simply and efficiently both short-term and long-term extreme response statistics. The results presented are based on extensive simulation results for the large fixed platform operating on the Norwegian Continental Shelf. Measured response time histories were used to validate numerical results.

Monte Carlo Simulation of Radiation in Gases With a Narrow-Band Model and a Net-Exchange Formulation

1996 ◽  
Vol 118 (2) ◽  
pp. 401-407 ◽  
Author(s):  
M. Cherkaoui ◽  
J.-L. Dufresne ◽  
R. Fournier ◽  
J.-Y. Grandpeix ◽  
A. Lahellec
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Radiative Heat ◽  
Computation Time ◽  
Band Model ◽  
One Dimensional ◽  
The Monte Carlo Method ◽  
Reflecting Surfaces ◽  
Heat Transfers ◽  
Narrow Band Model

The Monte Carlo method is used for simulation of radiative heat transfers in nongray gases. The proposed procedure is based on a Net-Exchange Formulation (NEF). Such a formulation provides an efficient way of systematically fulfilling the reciprocity principle, which avoids some of the major problems usually associated with the Monte Carlo method: Numerical efficiency becomes independent of optical thickness, strongly nonuniform grid sizes can be used with no increase in computation time, and configurations with small temperature differences can be addressed with very good accuracy. The Exchange Monte Carlo Method (EMCM) is detailed for a one-dimensional slab with diffusely or specularly reflecting surfaces.

A Monte Carlo Approach to Prediction of Extreme Response Statistics of Drag Dominated Offshore Structures

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Arvid Naess ◽  
Oleg Gaidai
Keyword(s):  
Monte Carlo ◽  
Weather Conditions ◽  
Offshore Structures ◽  
Drag Forces ◽  
Wave Elevation ◽  
The Monte Carlo Method ◽  
Strong Current ◽  
Highly Nonlinear ◽  
Extreme Response

The focus of the present paper is the extreme response statistics of drag dominated offshore structures subjected to harsh weather conditions. More specifically, severe sea states both with and without strong current are considered. The nature of the hydrodynamic forces acting on the structure becomes highly nonlinear. In addition to the drag forces, the so called inundation effect due to the wave elevation, corrected to include second order waves, is also taken into account. In the present paper, the Monte Carlo method along with a special extrapolation technique is applied. The proposed method opens up for the possibility to predict simply and efficiently long-term extreme response statistics, which is an important issue for the design of offshore structures.

UGR CALCULATION BASED ON THE LUMINANCE SPATIAL-ANGULAR DISTRIBUTION

2020 ◽  
Vol 2020 (4) ◽  
pp. 25-32
Author(s):  
Viktor Zheltov ◽  
Viktor Chembaev
Keyword(s):  
Monte Carlo ◽  
Angular Distribution ◽  
Monte Carlo Method ◽  
Visual Task ◽  
New Method ◽  
Lighting System ◽  
Preliminary Assessment ◽  
System A ◽  
The Monte Carlo Method

The article has considered the calculation of the unified glare rating (UGR) based on the luminance spatial-angular distribution (LSAD). The method of local estimations of the Monte Carlo method is proposed as a method for modeling LSAD. On the basis of LSAD, it becomes possible to evaluate the quality of lighting by many criteria, including the generally accepted UGR. UGR allows preliminary assessment of the level of comfort for performing a visual task in a lighting system. A new method of "pixel-by-pixel" calculation of UGR based on LSAD is proposed.

PSHA software review based on the Monte Carlo method

2020 ◽  
pp. 14-24
Author(s):  
V.A. Mironov ◽  
S.A. Peretokin ◽  
K.V. Simonov
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Seismic Hazard ◽  
Hazard Analysis ◽  
Software Review ◽  
Seismic Hazard Analysis ◽  
Probabilistic Seismic Hazard ◽  
Test Calculation ◽  
Seismic Surveys ◽  
The Monte Carlo Method

The article is a continuation of the software research to perform probabilistic seismic hazard analysis (PSHA) as one of the main stages in engineering seismic surveys. The article provides an overview of modern software for PSHA based on the Monte Carlo method, describes in detail the work of foreign programs OpenQuake Engine and EqHaz. A test calculation of seismic hazard was carried out to compare the functionality of domestic and foreign software.

Application of the Monte Carlo Method for the Prediction of Behavior of Peptides

2019 ◽  
Vol 20 (12) ◽  
pp. 1151-1157 ◽  
Author(s):  
Alla P. Toropova ◽  
Andrey A. Toropov
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Natural Sciences ◽  
Monte Carlo Technique ◽  
Quantitative Structure ◽  
Structure Property ◽  
The Monte Carlo Method ◽  
Modern Natural

Prediction of physicochemical and biochemical behavior of peptides is an important and attractive task of the modern natural sciences, since these substances have a key role in life processes. The Monte Carlo technique is a possible way to solve the above task. The Monte Carlo method is a tool with different applications relative to the study of peptides: (i) analysis of the 3D configurations (conformers); (ii) establishment of quantitative structure – property / activity relationships (QSPRs/QSARs); and (iii) development of databases on the biopolymers. Current ideas related to application of the Monte Carlo technique for studying peptides and biopolymers have been discussed in this review.

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