scholarly journals A Sensitivity-Based Approach for Reliability Analysis of Randomly Excited Structures With Interval Axial Stiffness

2020 ◽  
Vol 6 (4) ◽  
Author(s):  
Alba Sofi ◽  
Giuseppe Muscolino ◽  
Filippo Giunta
Keyword(s):  
Reliability Analysis ◽  
Interval Analysis ◽  
Structural Reliability ◽  
Reliability Function ◽  
Extreme Value ◽  
Axial Stiffness ◽  
Engineering Practice ◽  
Stress Process ◽  
Rational Series ◽  
Interval Reliability

Abstract Reliability assessment of linear discretized structures with interval parameters subjected to stationary Gaussian multicorrelated random excitation is addressed. The interval reliability function for the extreme value stress process is evaluated under the Poisson assumption of independent up-crossing of a critical threshold. Within the interval framework, the range of stress-related quantities may be significantly overestimated as a consequence of the so-called dependency phenomenon, which arises due to the inability of the classical interval analysis to treat multiple occurrences of the same interval variables as dependent ones. To limit undesirable conservatism in the context of interval reliability analysis, a novel sensitivity-based procedure relying on a combination of the interval rational series expansion and the improved interval analysis via extra unitary interval is proposed. This procedure allows us to detect suitable combinations of the endpoints of the uncertain parameters which yield accurate estimates of the lower bound and upper bound of the interval reliability function for the extreme value stress process. Furthermore, sensitivity analysis enables to identify the most influential parameters on structural reliability. A numerical application is presented to demonstrate the accuracy and efficiency of the proposed method as well as its usefulness in view of decision-making in engineering practice.

Reliability analysis for a hypersonic aircraft’s wing spar

2019 ◽  
Vol 91 (4) ◽  
pp. 549-557
Author(s):  
Yuhui Wang ◽  
Peng Shao ◽  
Qingxian Wu ◽  
Mou Chen
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Strength Degradation ◽  
Structural Safety ◽  
Engineering Practice ◽  
Flight Safety ◽  
Content Type ◽  
Hypersonic Aircraft ◽  
Analysis Scheme ◽  
Wing Spar

Purpose This paper aims to present a novel structural reliability analysis scheme with considering the structural strength degradation for the wing spar of a generic hypersonic aircraft to guarantee flight safety and structural reliability. Design/methodology/approach A logarithmic model with strength degradation for the wing spar is constructed, and a reliability model of the wing spar is established based on stress-strength interference theory and total probability theorem. Findings It is demonstrated that the proposed reliability analysis scheme can obtain more accurate structural reliability and failure results for the wing spar, and the strength degradation cannot be neglected. Furthermore, the obtained results will provide an important reference for the structural safety of hypersonic aircraft. Research limitations/implications The proposed reliability analysis scheme has not implemented in actual flight, as all the simulations are conducted according to the actual experiment data. Practical implications The proposed reliability analysis scheme can solve the structural life problem of the wing spar for hypersonic aircraft and meet engineering practice requirements, and it also provides an important reference to guarantee the flight safety and structural reliability for hypersonic aircraft. Originality/value To describe the damage evolution more accurately, with consideration of strength degradation, flight dynamics and material characteristics of the hypersonic aircraft, the stress-strength interference method is first applied to analyze the structural reliability of the wing spar for the hypersonic aircraft. The proposed analysis scheme is implemented on the dynamic model of the hypersonic aircraft, and the simulation demonstrates that a more reasonable reliability result can be achieved.

Structural Reliability Analysis with Uncertainty-but-Bounded Parameters Based on Meshless Method

2010 ◽  
Vol 163-167 ◽  
pp. 3034-3041
Author(s):  
Wei Zhao ◽  
J.K. Liu ◽  
Qiu Wei Yang
Keyword(s):  
Reliability Analysis ◽  
Meshless Method ◽  
Reliability Index ◽  
Structural Reliability ◽  
Strain Analysis ◽  
Optimization Theory ◽  
Upper And Lower Bounds ◽  
Probability Method ◽  
Structural Reliability Analysis ◽  
Interval Reliability

The structural reliability analysis with uncertainty-but-bounded parameters is considered in this paper. Each uncertain-but-bounded parameter is represented as an interval number or vector, an interval reliability index is defined and discussed. Due to the wide application of the Meshless method, it is used in structural stress and strain analysis. The target variable of requiring reliability analysis is estimated via Taylor expansion. Based on optimization theory and vertex solution theorem, the upper and lower bounds of the target variables are obtained, and also the interval reliability index. A typical elastostatics example is presented to illustrate the computational aspects of interval reliability analysis in comparison with the traditional probability method, it can be seen that the result calculated by the vertex solution theorem is consistent with that calculated by probability method.

A new method for structural non-probabilistic reliability analysis based on interval analysis

2016 ◽  
Vol 12 (1) ◽  
pp. 73-79
Author(s):  
Xing-wang Gou ◽  
Ai-jun Li ◽  
La-quan Luo ◽  
Chang-qing Wang
Keyword(s):  
Reliability Analysis ◽  
Lower Limit ◽  
Reliability Index ◽  
Structural Reliability ◽  
Solution Method ◽  
Interval Length ◽  
Structural Safety ◽  
Structural Uncertainty ◽  
Content Type ◽  
Interval Reliability

Purpose – The purpose of this paper is to propose a robust reliability index to characterize the structural safety degree. Design/methodology/approach – On the basis of the interval theory, a new interval reliability analysis method that the structural basic variables are described by the interval lower limit and interval length to characterize the structural uncertainty is proposed in this paper. Findings – A novel structural reliability index solution method is proposed. Besides, both linear and non-linear problem of solving interval non-probabilistic reliability are further discussed in this paper. Originality/value – Based on interval theory, variables are described by interval lower limit and interval length to characterize the structural uncertainty. A novel structural reliability index solution method is proposed.

STRUCTURAL RELIABILITY ANALYSIS BASED ON P-BOXES

2020 ◽  
Vol 92 (6) ◽  
pp. 51-58
Author(s):  
S.A. SOLOVYEV ◽  
Keyword(s):  
Probability Distribution ◽  
Reliability Analysis ◽  
Structural Reliability ◽  
Epistemic Uncertainty ◽  
Random Variable ◽  
Strength Criterion ◽  
Structural Elements ◽  
Structural Element ◽  
Limit States ◽  
Distribution Shape

The article describes a method for reliability (probability of non-failure) analysis of structural elements based on p-boxes. An algorithm for constructing two p-blocks is shown. First p-box is used in the absence of information about the probability distribution shape of a random variable. Second p-box is used for a certain probability distribution function but with inaccurate (interval) function parameters. The algorithm for reliability analysis is presented on a numerical example of the reliability analysis for a flexural wooden beam by wood strength criterion. The result of the reliability analysis is an interval of the non-failure probability boundaries. Recommendations are given for narrowing the reliability boundaries which can reduce epistemic uncertainty. On the basis of the proposed approach, particular methods for reliability analysis for any structural elements can be developed. Design equations are given for a comprehensive assessment of the structural element reliability as a system taking into account all the criteria of limit states.

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.

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