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.

scholarly journals Time-Dependent Reliability Analysis of Reinforced Concrete Beams Subjected to Uniform and Pitting Corrosion and Brittle Fracture

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1820
Author(s):  
Mohamed El Amine Ben Seghier ◽  
Behrooz Keshtegar ◽  
Hussam Mahmoud
Keyword(s):  
Reinforced Concrete ◽  
Brittle Fracture ◽  
Reliability Analysis ◽  
Pitting Corrosion ◽  
Structural Reliability ◽  
Time Dependent ◽  
State Function ◽  
Rc Beams ◽  
Highly Nonlinear ◽  
Reliability Method

Reinforced concrete (RC) beams are basic elements used in the construction of various structures and infrastructural systems. When exposed to harsh environmental conditions, the integrity of RC beams could be compromised as a result of various deterioration mechanisms. One of the most common deterioration mechanisms is the formation of different types of corrosion in the steel reinforcements of the beams, which could impact the overall reliability of the beam. Existing classical reliability analysis methods have shown unstable results when used for the assessment of highly nonlinear problems, such as corroded RC beams. To that end, the main purpose of this paper is to explore the use of a structural reliability method for the multi-state assessment of corroded RC beams. To do so, an improved reliability method, namely the three-term conjugate map (TCM) based on the first order reliability method (FORM), is used. The application of the TCM method to identify the multi-state failure of RC beams is validated against various well-known structural reliability-based FORM formulations. The limit state function (LSF) for corroded RC beams is formulated in accordance with two corrosion types, namely uniform and pitting corrosion, and with consideration of brittle fracture due to the pit-to-crack transition probability. The time-dependent reliability analyses conducted in this study are also used to assess the influence of various parameters on the resulting failure probability of the corroded beams. The results show that the nominal bar diameter, corrosion initiation rate, and the external loads have an important influence on the safety of these structures. In addition, the proposed method is shown to outperform other reliability-based FORM formulations in predicting the level of reliability in RC beams.

scholarly journals DEVELOPED PROBABILISTIC REDUCTION FACTORS FOR LOPHIRA ALATA (EKKI) TIMBER JOISTS SUBJECTED TO CREEP-RUPTURE

2016 ◽  
Vol 36 (1) ◽  
pp. 39-44
Author(s):  
JM Kaura ◽  
A Lawan ◽  
AA Salihu
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Significant Loss ◽  
Creep Rupture ◽  
Time Dependent ◽  
Load Duration ◽  
Design Variables ◽  
Reliability Method ◽  
Load Carrying ◽  
Strength And Stiffness

Wood experiences a significant loss of strength and stiffness when loaded over period of time. This phenomenon is known as creep-rupture. Several models were developed for the estimation of the reduction of load carrying capacity of timber with time. In this paper, the results of time dependent structural reliability analysis of timber joist produced with Lophiraalata (Ekki) timber specie was presented. Three load duration models were considered in the study, namely: The Model proposed by Wood, Gerhards model, and Nielsen. The timber joist was designed in accordance with the Eurocode 5. The uncertainties in all the basic design variables were fully accommodated in the time dependent reliability analysis. The entire process was implemented using a developed MATLAB program employing First Order Reliability Method (FORM). Time dependent mathematical models for modification of safety index to account for the effect of load duration were proposed. The use of both Gerhards and Nielsen model, for the design of Lophiraalata timber members was recommended.  http://dx.doi.org/10.4314/njt.v36i1.6

Ship Hull Ultimate Strength Reliability Considering Corrosion

1998 ◽  
Vol 42 (02) ◽  
pp. 154-165
Author(s):  
Jeom Kee Paik ◽  
Anil K. Thayamballi ◽  
Sung Kyu Kim ◽  
Soo Hong Yang
Keyword(s):  
Ultimate Strength ◽  
Reliability Index ◽  
Failure Modes ◽  
Ship Hull ◽  
Time Dependent ◽  
General Corrosion ◽  
Wave Load ◽  
Hull Girder ◽  
Corrosion Rates ◽  
Reliability Method

The aim of the present paper is to develop and demonstrate a procedure for assessment of ship hull girder ultimate strength reliability taking into account the degradation of primary members due to general corrosion. The probabilistic model for ultimate hull girder strength is established on the basis of an analytical formula that considers corrosion related time dependent strength degradation in the various failure modes. Corrosion rates and their probabilistic characterization are based on available studies using gauging data. Applicable extreme hull girder loads are calculated using a simplified direct method for wave load calculation together with the IACS design guidance formula for stillwater bending moment. The variability in strength, corrosion rates and loads are accounted for in the second order reliability method (SORM) based on calculations of the time dependent reliability index. The procedure developed is illustrated by application to both tankers and bulk carriers. For a given set of renewal criteria, apart from trends of hull girder section modulus, ultimate strength and the reliability index as a function of vessel age, the probability of steel renewal due to corrosion is also predicted.

scholarly journals A Probabilistic Physics of Failure Approach for Structure Corrosion Reliability Analysis

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Chaoyang Xie ◽  
Hong-Zhong Huang
Keyword(s):  
Reliability Analysis ◽  
Pitting Corrosion ◽  
Structural Reliability ◽  
Corrosion Damage ◽  
Failure Model ◽  
Metallic Structures ◽  
Corrosion Failure ◽  
Physics Of Failure ◽  
Reliability Method ◽  
Safety Operation

Corrosion is recognized as one of the most important degradation mechanisms that affect the long-term reliability and integrity of metallic structures. Studying the structural reliability with pitting corrosion damage is useful for risk control and safety operation for the corroded structure. This paper proposed a structure corrosion reliability analysis approach based on the physics-based failure model of pitting corrosion, where the states of pitting growth, pit-to-crack, and cracking propagation are included in failure model. Then different probabilistic analysis methods such as Monte-Carlo Simulation (MCS), First-Order Reliability Method (FORM), Second-Order Reliability Method (SORM), and response surface method are employed to calculate the reliability. At last, an example is presented to demonstrate the capability of the proposed structural reliability model and calculating methods for structural corrosion failure analysis.

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.

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.

Time-Dependent Reliability Analysis Through Response Surface Method

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Dequan Zhang ◽  
Xu Han ◽  
Chao Jiang ◽  
Jie Liu ◽  
Qing Li
Keyword(s):  
Reliability Analysis ◽  
Response Surface ◽  
Structural Reliability ◽  
Time Dependent ◽  
Gaussian Stochastic Process ◽  
Reliability Indices ◽  
Novel Approach ◽  
Reliability Method ◽  
Optimal Linear ◽  
Uncertain Structures

In time-dependent reliability analysis, the first-passage method has been extensively used to evaluate structural reliability under time-variant service circumstances. To avoid computing the outcrossing rate in this method, surrogate modeling may provide an effective alternative for calculating the time-dependent reliability indices in structural analysis. A novel approach, namely time-dependent reliability analysis with response surface (TRARS), is thus introduced in this paper to estimate the time-dependent reliability for nondeterministic structures under stochastic loads. A Gaussian stochastic process is generated by using the expansion optimal linear estimation (EOLE) method which has proven to be more accurate and efficient than some series expansion discretization techniques. The random variables and maximum responses of uncertain structures are treated as the input and output parameters, respectively. Through introducing the response surface (RS) model, a novel iterative procedure is proposed in this study. A Bucher strategy is adopted to generate the initial sample points, and a gradient projection technique is used to generate new sampling points for updating the RS model in each iteration. The time-dependent reliability indices and probabilities of failure are thus obtained efficiently using the first-order reliability method (FORM) over a certain design lifetime. In this study, four demonstrative examples are provided for illustrating the accuracy and efficiency of the proposed method.

Some Important Issues on First-Order Reliability Analysis With Nonprobabilistic Convex Models

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
C. Jiang ◽  
G. Y. Lu ◽  
X. Han ◽  
R. G. Bi
Keyword(s):  
Reliability Analysis ◽  
Reliability Index ◽  
Probability Model ◽  
Mean Value ◽  
Convex Model ◽  
First Order ◽  
Reliability Method ◽  
Complex Engineering ◽  
Mean Value Method ◽  
Form Type

Compared with the probability model, the convex model approach only requires the bound information on the uncertainty, and can make it possible to conduct the reliability analysis for many complex engineering problems with limited samples. Presently, by introducing the well-established techniques in probability-based reliability analysis, some methods have been successfully developed for convex model reliability. This paper aims to reveal some different phenomena and furthermore some severe paradoxes when extending the widely used first-order reliability method (FORM) into the convex model problems, and whereby provide some useful suggestions and guidelines for convex-model-based reliability analysis. Two FORM-type approximations, namely, the mean-value method and the design-point method, are formulated to efficiently compute the nonprobabilistic reliability index. A comparison is then conducted between these two methods, and some important phenomena different from the traditional FORMs are summarized. The nonprobabilistic reliability index is also extended to treat the system reliability, and some unexpected paradoxes are found through two numerical examples.

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