Non-Probabilistic Structural Reliability Model Based on Ellipsoidal-Bound Model with Restricted Expansion

2011 ◽  
Vol 230-232 ◽  
pp. 920-924
Author(s):  
Kun Feng Li ◽  
Zi Chun Yang ◽  
Gui Feng Liu
Keyword(s):  
Reliability Index ◽  
Structural Reliability ◽  
Insufficient Data ◽  
Reliability Model ◽  
Gap Model ◽  
New Model ◽  
Model Based ◽  
Information Gap ◽  
Reliability Method

When insufficient data are available, probabilistic reliability method is invalid, but the non-probabilistic reliability method based on I-G (information-gap) model is a valid alternative. The most common I-G model, ellipsoidal-bound model, has been updated in this paper by acquiring information about span restrictions of uncertainty quantities and a corresponding non-probabilistic reliability index was proposed. The method for computing the reliability index was also given. The new model can reveal the influence of the span restriction of uncertainty quantities on structural reliability.

Non-Probabilistic Structural Reliability Model Based on Ellipsoidal-Bound Model with Nonlinear Expansion

2011 ◽  
Vol 65 ◽  
pp. 264-267
Author(s):  
Kun Feng Li ◽  
Zi Chun Yang ◽  
Wen Cai Sun
Keyword(s):  
Calculation Method ◽  
Reliability Index ◽  
Structural Reliability ◽  
Reliability Model ◽  
Gap Model ◽  
Model Based

Info-gap model is the foundation of the non-probabilistic reliability model. In this paper, ellipsoidal-bound model which is the most common Info-gap model has been updated by acquiring restriction information about uncertain quantities. The initial ellipsoidal-bound model can be degenerated from the updated model. A non-probabilistic structural reliability model based on the updated ellipsoidal-bound model was established. A non-probabilistic reliability index was proposed and the calculation method was also given. The example shows that the introduction of restriction information is valid, and the new non-probabilistic reliability model can reveal the influence of the span restriction of uncertain quantities on structural reliability.

System Reliability of Existing Jacket Platform in Malaysian Water (Failure Path and System Reliability Index)

2014 ◽  
Vol 567 ◽  
pp. 307-312 ◽  
Author(s):  
V. John Kurian ◽  
Mohamed Mubarak Abdul Wahab ◽  
T.S. Kheang ◽  
Mohd Shahir Liew
Keyword(s):  
System Reliability ◽  
Reliability Index ◽  
Structural Reliability ◽  
Pushover Analysis ◽  
Probability Of Failure ◽  
Jacket Platform ◽  
First Order ◽  
Failure Path ◽  
Reliability Method ◽  
Two Parameters

The objective of this work is to determine the structural reliability of an existing jacket platform in Malaysia, by determining the system probability of failure and its corresponding reliability index. These two parameters are important indicators for assessing the integrity and reliability of the platform, and will point out whether the platform is suitable for continued operation. In this study, pushover analysis is used to determine possible failure paths of the structure, while First Order Reliability Method (FORM) and Simple Bound Formula are used to determine the failure probability and reliability index. Three failure paths of the platform are established. The reliability index of these paths is found with the highest Reliability Indexto be 18.82 from the 315-degree path, while the system reliability index is 9.23. This illustrates that the platform is robust and the chances of collapse is very small.

Neural network approach to model the limit state surface for reliability analysis

2003 ◽  
Vol 40 (6) ◽  
pp. 1235-1244 ◽  
Author(s):  
Anthony TC Goh ◽  
Fred H Kulhawy
Keyword(s):  
Neural Network ◽  
Reliability Index ◽  
Structural Reliability ◽  
Limit State ◽  
Random Variables ◽  
First Order Reliability Method ◽  
First Order ◽  
The Neural Network ◽  
Reliability Method ◽  
Geotechnical Structures

Structural reliability methods are often used to evaluate the failure performance of geotechnical structures. A common approach is to use the first-order reliability method. Its popularity results from the mathematical simplicity of the method, since only second moment information (mean and coefficient of variation) on the random variables is required. The probability of failure is then assessed by an index known commonly as the reliability index. One critical aspect in determining the reliability index is the explicit definition of the limit state surface of the system. In a problem involving multi-dimensional random variables, the limit state surface is the boundary separating the safe domain from the "failure" (or lack of serviceability) domain. In many complicated and nonlinear problems where the analyses involve the use of numerical procedures such as the finite element method, this surface may be difficult to determine explicitly in terms of the random variables, and therefore the limit state can only be expressed implicitly rather than in a closed-form solution. It is proposed in this paper to use an artificial intelligence technique known as the back-propagation neural network algorithm to model the limit state surface. First, the failure domain is found through repeated point-by-point numerical analyses with different input values. The neural network is then trained on this set of data. Using the optimal weights of the neural network connections, it is possible to develop a mathematical expression relating the input and output variables that approximates the limit state surface. Some examples are given to illustrate the application and accuracy of the proposed approach.Key words: first-order reliability method, geotechnical structures, limit state surface, neural networks, reliability.

Study of Computation for Structural Reliability Index Based on Penalty Function Method

2014 ◽  
Vol 635-637 ◽  
pp. 443-446 ◽  
Author(s):  
Hai Tao Lu ◽  
Yu Ge Dong ◽  
Fang Ying Wu
Keyword(s):  
Unconstrained Optimization ◽  
Penalty Function ◽  
Reliability Index ◽  
Function Method ◽  
Structural Reliability ◽  
Limit State ◽  
State Function ◽  
Penalty Function Method ◽  
Design Point ◽  
Reliability Method

According to the geometric meaning of the structural reliability index, an unconstrained optimization model with structural reliability index and design point is obtained by exterior penalty function method. The Powell method, golden section method and extrapolation method are used to solve the unconstrained optimization problem. The proposed method not has to deal with the any derivative of the limited state function, and can been used to obtain structural reliability index and design point of the strong nonlinear limit state function, which first-order reliability method (FORM) may fail to converge. Three examples are given to compare penalty function method with the difference methods. The results show that the given method is simply, effective and precise enough.

scholarly journals Time-Dependent Reliability Analysis of Plate-Stiffened Prismatic Pressure Vessel with Corrosion

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1544
Author(s):  
Younseok Choi ◽  
Junkeon Ahn ◽  
Daejun Chang
Keyword(s):  
Reliability Analysis ◽  
Pitting Corrosion ◽  
Pressure Vessel ◽  
Reliability Index ◽  
Structural Reliability ◽  
Pressure Vessels ◽  
Outer Shell ◽  
Time Dependent ◽  
General Corrosion ◽  
Reliability Method

In this study, the structural reliability of plate-stiffened prismatic pressure vessels was analyzed over time. A reliability analysis was performed using a time-dependent structural reliability method based on the response surface method (RSM). The plate-stiffened prismatic pressure vessel had a rectangular cross-section with repeated internal load-bearing structures. For the structural analysis, this repeated structure was modeled as a strip, and a structural reliability analysis was performed to identify changes in the reliability index when general corrosion and pitting corrosion occurred in the outer shell. Pitting corrosion was assumed to be randomly distributed on the outer shell, and the reliability index according to the degree of pit (DOP) and time was analyzed. Analysis results confirmed that the change in the reliability index was larger when pitting corrosion was applied compared with when only general corrosion was applied. Additionally, it was confirmed that above a certain DOP, the reliability index was affected.

Structural Reliability Applications in Design and Maintenance Planning of Ships Subjected to Fatigue and Corrosion

2012 ◽  
Author(s):  
Marcos Corrêa Câmara ◽  
Júlio C. Ramalho Cyrino
Keyword(s):  
Reliability Index ◽  
Structural Reliability ◽  
Time Dependent ◽  
Maintenance Planning ◽  
Inspection Planning ◽  
Utilization Factor ◽  
Hull Girder ◽  
Target Reliability Index ◽  
Hull Structure ◽  
Reliability Method

This paper presents structural reliability applications in design and maintenance planning for ships hull structures. For the assessment of structural strength, the model developed consists in an ultimate limit-state of hull-girder considering degradation by corrosion based in a statistical investigation of time-variant hull girder strength made by ABS (American Bureau of Shipping) on 2007. The time dependent reliability index obtained with the minimum elastic section modulus required by the rules of the classification society American Bureau of shipping (ABS), of two ship designs are compared against the results obtained from the target reliability index based design. The target reliability index assessment for corroded hulls is also showed. The monte-carlo simulation reliability method is used to calculate the time-dependent reliability of the primary hull structure. Two approaches of fatigue and corrosion-enhanced fatigue time dependent reliability are developed. A long term stress range applied to a detail is fitted to a weibull distribution based in a known design life. A utilization factor is introduced in order to consider the fraction of time at sea. A risk-based inspection planning is discussed for commercial and naval vessels Both S-N curve and fracture mechanics based reliability methods are used and the results are compared. An example of reliability updating after a inspection result is showed.

Assessment of the structural reliability of loadbearing concrete masonry designed to the Canadian Standard S304.1

2014 ◽  
Vol 41 (12) ◽  
pp. 1046-1053
Author(s):  
Hadi Moosavi ◽  
Yasser Korany
Keyword(s):  
Reliability Analysis ◽  
Reliability Index ◽  
Structural Reliability ◽  
Resistance Factor ◽  
Dead Load ◽  
Design Standard ◽  
Concrete Masonry ◽  
Reliability Method ◽  
Masonry Material ◽  
Acceptable Reliability

A structural reliability analysis was performed on concrete masonry under axial compression using the First Order Reliability Method (FORM) to assess the reliability levels under the current (2004) and preceding (1994) editions of the Canadian masonry design standard S304.1. The Hasofer–Lind reliability index was evaluated at different live-to-dead load and snow-to-dead load ratios using the Rackwitz–Fiessler procedure. The reliability analysis revealed that neither the masonry material resistance factor of 0.6 adopted in the current Canadian masonry design standard (S304.1-04) nor the previous value of 0.55 in its predecessor (S304.1-94) achieve acceptable reliability levels for masonry in compression under combined dead and live or snow loads. Reliability levels close to the target reliability index recommended by the Canadian standard S408-11 and the levels evaluated for concrete in compression designed to the Canadian standard A23.3-04 were achieved when a masonry material resistance factor of 0.5 was used.

The Solution of the Structural Reliability Index Based on SAPSO

2011 ◽  
Vol 138-139 ◽  
pp. 410-415
Author(s):  
Ke Tong Liu ◽  
Ai Ping Tang
Keyword(s):  
Simulated Annealing ◽  
Optimization Algorithm ◽  
Reliability Index ◽  
Structural Reliability ◽  
Complex Structure ◽  
Particle Swarm ◽  
Particle Swarm Algorithm ◽  
Local Optimum ◽  
Reliability Method ◽  
Swarm Algorithm

In view of the shortcoming of the existing structural reliability calculation method, this paper establishes optimization model of the structural reliability index from the geometric meaning of the structural reliability index. Then, the authors propose a method based on improved particle swarm optimization algorithm for solving the reliability method. Particle swarm algorithm is easy to fall into local optimum. So, the authors construct simulated annealing particle swarm algorithm which has the strong local search ability .simulated annealing particle swarm algorithm is a global optimization algorithm. Using it to solve the reliability index can avoid doing partial derivatives to the structural performance function and the deficiency of traditional method is effectively overcomed which is easily being trapped in local optima. Therefore, it is a very effective method to solving the structural reliability index of the complex structure. In the end, some examples demonstrate the validity of this method.

Improved bat algorithm for structural reliability assessment: application and challenges

2016 ◽  
Vol 12 (2) ◽  
pp. 218-253 ◽  
Author(s):  
Asma Chakri ◽  
Rabia Khelif ◽  
Mohamed Benouaret
Keyword(s):  
Reliability Analysis ◽  
Reliability Index ◽  
Structural Reliability ◽  
Limit State ◽  
Computing Time ◽  
Bat Algorithm ◽  
Normal Space ◽  
Content Type ◽  
Reliability Method ◽  
Adaptive Penalty

Purpose – The first order reliability method requires optimization algorithms to find the minimum distance from the origin to the limit state surface in the normal space. The purpose of this paper is to develop an improved version of the new metaheuristic algorithm inspired from echolocation behaviour of bats, namely, the bat algorithm (BA) dedicated to perform structural reliability analysis. Design/methodology/approach – Modifications have been embedded to the standard BA to enhance its efficiency, robustness and reliability. In addition, a new adaptive penalty equation dedicated to solve the problem of the determination of the reliability index and a proposition on the limit state formulation are presented. Findings – The comparisons between the improved bat algorithm (iBA) presented in this paper and other standard algorithms on benchmark functions show that the iBA is highly efficient, and the application to structural reliability problems such as the reliability analysis of overhead crane girder proves that results obtained with iBA are highly reliable. Originality/value – A new iBA and an adaptive penalty equation for handling equality constraint are developed to determine the reliability index. In addition, the low computing time and the ease implementation of this method present great advantages from the engineering viewpoint.

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