scholarly journals Heuristic Operator for Reliability Assessment of Frame Structures

2021 ◽  
Author(s):  
Ali Kaveh ◽  
Seyed Rohollah Hoseini Vaez ◽  
Pedram Hosseini ◽  
Mohammad Ali Fathali
Keyword(s):  
Reliability Index ◽  
Limit State ◽  
Simulation Method ◽  
Frame Structures ◽  
State Function ◽  
Limit State Function ◽  
Cross Sectional ◽  
Story Drift ◽  
Steel Frame Structures ◽  
External Loads

In structural design of steel frames, in order to achieve proper safety, the effect of uncertainties in the design and loading parameters of the structure must be considered. This approach is obtained by defining a reliability index. In this study, the Modified Dolphin Monitoring (MDM) operator was used to evaluate the reliability index of three well-known steel frame structures based on the Hasofer-Lind method. The reliability index was evaluated using the EVPS and VPS algorithms and with considering the MDM operator on them. The constraint of the last story drift is considered as limit state function. The random variables consist of external loads, modulus of elasticity, moment of inertia and cross-sectional areas. According to the number of evaluations of the limit state function, the results show the efficiency of this method in comparison to the Monte Carlo simulation method. Also, the values of the most probable point (MPP) are examined.

Inversion analysis to determine design parameters for reliability assessment in pavement structures

2014 ◽  
Vol 41 (10) ◽  
pp. 845-855 ◽  
Author(s):  
Sungho Mun
Keyword(s):  
Reliability Index ◽  
Limit State ◽  
Reliability Assessment ◽  
Pavement Performance ◽  
Design Parameters ◽  
State Function ◽  
Limit State Function ◽  
Performance Function ◽  
Pavement Structures ◽  
Inversion Analysis

Reliability assessment has been used to evaluate the performance of pavement structures. However, probabilistic inversion analysis of pavement structure design has not yet been tested to determine the design parameters of the pavement performance function, given a specified reliability index. In this study, a limit state function numerical calculation and the inversion technique of the Nelder–Mead simplex algorithm were used to determine the design parameters for the pavement performance function. The method of moments was used to develop the forward limit state function, which was then compared to Monte Carlo simulations; the comparison indicated good agreement between the two methods. Additionally, several cases were studied to determine the design parameters of the pavement performance function for the reliability index specified in this study. The case studies indicated that the structure number significantly affected the pavement performance function.

scholarly journals High Dimension Model Representation-Based Response Surface for Reliability Analysis of Tunnel

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Hongbo Zhao
Keyword(s):  
Reliability Analysis ◽  
Response Surface ◽  
Reliability Index ◽  
Limit State ◽  
State Function ◽  
Limit State Function ◽  
Implicit Function ◽  
Surface Method ◽  
Reliability Method ◽  
Rock Tunnel

Uncertainty is an important prosperity to rock tunnel. Reliability analysis is widely used to deal with the uncertainty. But it is difficult to be adopted in rock tunnel using the traditional reliability method because the limit state function is an implicit function. High dimension model representation (HDMR) can approximate the high dimensional, nonlinear, and implicit function using the low dimensional function. In this study, the HDMR method was adapted to approximate the limit state function through combining with response surface method (RSM). A new reliability analysis approach of HDMR-based response surface method, combined with the first-order reliability method (FORM), is developed to calculate the reliability index of tunnel, and implementation of the method is explained briefly. A circular tunnel with analytical solution and horseshoe tunnel with numerical solution are used to demonstrate the proposed method. The obtained reliability index is in excellent agreement with Low and Tang’s (2007) method and traditional RSM. It shows that HDMR-based response surface can approximate well the limit state function, and the proposed method is an efficient and effective approach for reliability analysis in tunnel engineering. It is very useful for reliability analysis of practical large-scale rock engineering.

scholarly journals Spoke Model for Calculating Reliability Index and Safety Factor of Slopes

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Ping Wang ◽  
Dongyan Liu ◽  
Haibin Huang ◽  
Dongsheng Liu
Keyword(s):  
Reliability Analysis ◽  
Safety Factor ◽  
Reliability Index ◽  
Slip Surface ◽  
Limit State ◽  
Iterative Solution ◽  
Practical Method ◽  
State Function ◽  
Limit State Function ◽  
Searching Method

Considering the disadvantages of the slice method commonly employed in reliability analysis of slopes, a novel method (Spoke model) was proposed for reliability analysis and safety factor calculation of slopes in this work based on geometrical relationship among slices. The safety factor and the coefficients of limit state function of slopes could be achieved with the Gaussian integral method. The minimum safety factor and the minimum reliability index, as well as their corresponding coordinates on the slip surface, can be calculated with the improved JC method and the searching method. A novel and practical method for reliability analysis of slopes has been achieved. With this method the slice process could be avoided, which helps to eliminate some calculation errors caused by oversimplified assumption. Moreover, the explicit expression of safety factor in this method requires no repeated iterative solution, which is employed in traditional slice methods, as well as can be developed into a limit state function required by calculation of the reliability index. It is demonstrated that this method works efficiently and succinctly in evaluation of reliability index and safety factor for soil slopes.

scholarly journals An Energy-Based Limit State Function for Estimation of Structural Reliability in Shock Environments

2013 ◽  
Vol 20 (5) ◽  
pp. 933-950 ◽  
Author(s):  
Michael A. Guthrie
Keyword(s):  
Reliability Index ◽  
Structural Reliability ◽  
Limit State ◽  
Element Model ◽  
Monte Carlo Analysis ◽  
State Function ◽  
Limit State Function ◽  
Qualitative Comparison ◽  
Structural Capacity ◽  
Mass Spring

limit state function is developed for the estimation of structural reliability in shock environments. This limit state function uses peak modal strain energies to characterize environmental severity and modal strain energies at failure to characterize the structural capacity. The Hasofer-Lind reliability index is briefly reviewed and its computation for the energy-based limit state function is discussed. Applications to two degree of freedom mass-spring systems and to a simple finite element model are considered. For these examples, computation of the reliability index requires little effort beyond a modal analysis, but still accounts for relevant uncertainties in both the structure and environment. For both examples, the reliability index is observed to agree well with the results of Monte Carlo analysis. In situations where fast, qualitative comparison of several candidate designs is required, the reliability index based on the proposed limit state function provides an attractive metric which can be used to compare and control reliability.

Reliability Research of Building Fire Based on Numerical Simulation and Uniform Design

2011 ◽  
Vol 368-373 ◽  
pp. 665-672
Author(s):  
Su Fen Huang ◽  
Zhi Gang Song ◽  
Bin Li
Keyword(s):  
Numerical Simulation ◽  
Response Surface ◽  
Response Surface Method ◽  
Reliability Index ◽  
Limit State ◽  
Uniform Design ◽  
State Function ◽  
Limit State Function ◽  
Building Fire ◽  
Surface Method

Existing safety study of building fire is mainly based on the ISO834 temperature-time curve, which is a theoretical curve and not fully reflect the influencing factors of fire such as the distribution of fuel and ventilation of the building. Secondly, the reliability analysis of building fire lacks explicit limit state function, especially when the reliability calculation considers the internal force redistribution of the structure. Direct Monte Carlo simulation has no requirement of explicit limit state function, but it needs huge calculation efforts. To solve these two problems, the response surface method is proposed from the view point of numerical simulation and experiment design. Using the fire modeling software CFAST the actual result of temperature and thickness of smoke layer can be obtained. On this basis, the reliability index can be calculated with the response surface method，which can solve the problem of lacking explicit limit state function by regressing multi-variable function based on the inputs and outputs. Uniform design (UD) method can allocate more parameters without greatly increasing the calculation efforts. Using a case the calculation process is explained with. The results show that this method can quickly obtain the reliability index in the premise of less calculation.

scholarly journals RPCM: a strategy to perform reliability analysis using polynomial chaos and resampling

2010 ◽  
pp. 795-830
Author(s):  
Alban Notin ◽  
Nicolas Gayton ◽  
Jean Luc Dulong ◽  
Maurice Lemaire ◽  
Pierre Villon ◽  
...  
Keyword(s):  
Reliability Analysis ◽  
Reliability Index ◽  
Polynomial Chaos ◽  
Limit State ◽  
State Function ◽  
Limit State Function ◽  
New Approach ◽  
Stochastic Finite Elements ◽  
Polynomial Chaos Expansions ◽  
Computational Purpose

Using stochastic finite elements, the response quantity can be written as a series expansion which allows an approximation of the limit state function. For computational purpose, the series must be truncated in order to retain only a finite number of terms. In the context of reliability analysis, we propose a new approach coupling polynomial chaos expansions and confidence intervals on the generalized reliability index as truncating criterion.

scholarly journals Probabilistic Optimum Design of Aircraft Structures

2000 ◽  
Author(s):  
Landon Onyebueke ◽  
Ikechukwu Nnamani
Keyword(s):  
Optimum Design ◽  
Limit State ◽  
Simulation Method ◽  
Sensitivity Analyses ◽  
State Function ◽  
Limit State Function ◽  
Approximate Methods ◽  
Aircraft Structures ◽  
Stochastic Data ◽  
Search Approach

Abstract This paper discusses the application of probabilistic design methodology for the optimum design of aircraft structures. Material properties and loads are considered as stochastic data in formulating the optimization model for the design. The procedure accommodates various types of sensitivity analyses. Attention is focused on studies in which both the aerodynamic and structural designs are optimized simultaneously. Tradeoffs between drag and structural weight for aircraft wings are affected by two aerodynamic-structural interactions. First, structural weight affects the required lift and, thus drag. Second, structural deformations change the aerodynamic shape. Design results obtained using the Monte Carlo simulation method, and the limit state function approach, are presented. The limit state function method applies the Most Probable Point (MPP) search approach. Some of the approximate methods that have been applied for the search are FORM, AMV, AIS, etc.

An Efficient Response Surface Method Using Givens Transformation for Structural Reliability Analysis

2012 ◽  
Vol 532-533 ◽  
pp. 408-411
Author(s):  
Wei Tao Zhao ◽  
Yi Yang ◽  
Tian Jun Yu
Keyword(s):  
Response Surface ◽  
Response Surface Method ◽  
Structural Reliability ◽  
Limit State ◽  
State Function ◽  
Limit State Function ◽  
Surface Method ◽  
Mathematical Techniques ◽  
Input Variables ◽  
Improved Accuracy

The response surface method was proposed as a collection of statistical and mathematical techniques that are useful for modeling and analyzing a system which is influenced by several input variables. This method gives an explicit approximation of the implicit limit state function of the structure through a number of deterministic structural analyses. However, the position of the experimental points is very important to improve the accuracy of the evaluation of failure probability. In the paper, the experimental points are obtained by using Givens transformation in such way these experimental points nearly close to limit state function. A Numerical example is presented to demonstrate the improved accuracy and computational efficiency of the proposed method compared to the classical response surface method. As seen from the result of the example, the proposed method leads to a better approximation of the limit state function over a large region of the design space, and the number of experimental points using the proposed method is less than that of classical response surface method.

Development of Ultimate Strength Evaluation Method for Piping Subjected to Seismic Loads

2013 ◽  
Author(s):  
Hideo Machida ◽  
Hiromasa Chitose ◽  
Tatsuhiro Yamazaki
Keyword(s):  
Power Plants ◽  
Evaluation Method ◽  
Failure Modes ◽  
Limit State ◽  
Seismic Loading ◽  
Earthquake Resistance ◽  
State Function ◽  
Limit State Function ◽  
Input Acceleration ◽  
Resistance Tests

This paper reports the results of the study on the failure modes and limit loads of piping in nuclear power plants subjected to cyclic seismic loading. By investigating the past fracture tests and earthquake resistance tests, it became clear that dominant failure mode of piping was fatigue, and the effect of ratchet strain was negligible. Until now, the stress generated with the acceleration of an earthquake was classified into the primary stress. However, the relationship between the input acceleration and the seismic response displacement of the pipe observed from earthquake resistance tests is non-linear, and increasing rate of displacement is lower than that of input acceleration in elastic-plastic stress condition. Therefore, the seismic loading can be treated as displacement controlled loading. To evaluate the reliability-based critical acceleration, a limit state function was defined taking the variations in the fatigue strength or some parameters into consideration. By using the limit state function, the reliability was evaluated for the typical piping of boiling water reactor (BWR) plants subjected to cyclic seismic loading, and a partial safety factors were calculated. Based on these results, a fatigue curve corresponding to the target reliability was proposed.

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