A reliability based measure of structural robustness for coherent systems

2021 ◽  
Vol 89 ◽  
pp. 102050
Author(s):  
Baidurya Bhattacharya
Metrika ◽  
2021 ◽  
Author(s):  
Krzysztof Jasiński

AbstractIn this paper, we study the number of failed components of a coherent system. We consider the case when the component lifetimes are discrete random variables that may be dependent and non-identically distributed. Firstly, we compute the probability that there are exactly i, $$i=0,\ldots ,n-k,$$ i = 0 , … , n - k , failures in a k-out-of-n system under the condition that it is operating at time t. Next, we extend this result to other coherent systems. In addition, we show that, in the most popular model of independent and identically distributed component lifetimes, the obtained probability corresponds to the respective one derived in the continuous case and existing in the literature.


2021 ◽  
pp. 100084
Author(s):  
Yudong He ◽  
Xian Zhou ◽  
Jiahao Huo ◽  
Qun Zhang ◽  
Jinhui Yuan

Author(s):  
Qiwen Jin ◽  
Zheng Liu

In-service bridges, under long-term service operational environment, are usually accompanied by different damage types. Traditional method for the measure point arrangement of in-service bridge SHM is usually based on engineering experience. A large number of SHM sensors are usually arranged on the structure, followed by a high engineering cost and a heavy maintenance task. These sensors will also produce large amounts of data, creating a challenge for operators requiring to deal with data processing in an effective manner. This study serves as a part of the series of studies on the measure point arrangement strategy of in-service bridge SHM. In this study, the SHM sensor measure point arrangement of in-service continuous girder bridge (a common structural style of high way bridge in China) is proposed. Two-span continuous beam, three-span continuous beam, and four-span continuous beam are taken as examples. Detailed comparison and verification are also performed with consideration of numerical simulation and previous studies. Different traffic speeds and different bridge spans are considered. The effect of different damage locations and different damage degrees are analyzed in detail. This study shows that a general similar trend can be observed for the structural robustness of in-service continuous girder bridge. The elements with smaller structural robustness of this kind of bridge are basically located around the middle cross section of side spans (first span and last span), followed by the middle span. Moreover, the numerical value of structural robustness of different elements in a continuous girder bridge is significantly different from each other, due to the complexity of the joint effect of different traffic speeds and damage locations. Therefore, the measure point should be generally arranged at the side span firstly, followed by the middle span. With consideration of the specific traffic speed and damage location in engineering application, a detailed analysis is also proposed for the further optimization of SHM sensor measure point arrangement. Once the elements are arranged in order of the numerical value of structural robustness, the SHM sensor measure point arrangement of this kind of bridge can be more targeted, and the number of sensors can also be greatly reduced.


2011 ◽  
Vol 48 (03) ◽  
pp. 856-867 ◽  
Author(s):  
Jorge Navarro ◽  
Francisco J. Samaniego ◽  
N. Balakrishnan

Signature-based representations of the reliability functions of coherent systems with independent and identically distributed component lifetimes have proven very useful in studying the ageing characteristics of such systems and in comparing the performance of different systems under varied criteria. In this paper we consider extensions of these results to systems with heterogeneous components. New representation theorems are established for both the case of components with independent lifetimes and the case of component lifetimes under specific forms of dependence. These representations may be used to compare the performance of systems with homogeneous and heterogeneous components.


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