@article { author = {Ranjbaran, Abdolrasoul and Ranjbaran, Mohammad and Ranjbaran, Fatema}, title = {A Reliable Fracture Mechanics}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {3}, number = {1}, pages = {1-15}, year = {2020}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/IJRRS.3.1.1}, abstract = {    A branch of human knowledge, which treats the behavior of cracked structures, is called fracture mechanics. Since there is no intact structure in the world, then the paramount importance of fracture mechanics in human life is accentuated. The main parameter of fracture mechanics is called crack compliance, which is the amount of flexibility added to the flexibility of the intact structure due to the presence of a crack with specified size. The compliance, similar to flexibility, is the sole characteristics of the cracked structure. In this way for a given structure with a specified crack, there should be a single compliance. Unfortunately, in classical fracture mechanics that is not the case! The number of crack compliances for a clacked structure is equal to the number of researchers who treated the case! This diversity in the results stems from the presence of epistemic uncertainty in the mathematical basis of classical fracture mechanics. In view of the need for remedy, the Abdolrasoul Ranjbaran Team (ART), investigated the case and proposed a reliable fracture mechanics, which is based on sound logical reasoning. The proposed reliable fracture mechanics is described in the presented paper. The paper is managed via fourteen titles as, introduction, the mathematical basis of the classical fracture mechanics, birthplace of the state based philosophy, strong form of governing equation, analytical solution by Laplace transform, the weak form equation, the finite element equation, logical basis of the state based philosophy, state functions, Persian curves, reliable crack compliance, energy release rate, stress intensity factor, and weight function for the stress intensity factor in sections one to fourteen respectively. The paper concludes with a list of cited references.  }, keywords = {Classical fracture mechanics,reliable fracture mechanics,State based philosophy,Persian Curves,flexibility,crack compliance,Stress intensity factor,energy release rate}, url = {http://www.ijrrs.com/article_109239.html}, eprint = {http://www.ijrrs.com/article_109239_09a816c5df255fab21a13c24991e4fea.pdf} } @article { author = {Singh, Vijay and Gahlot, Monika}, title = {Stochastic Analysis of Complex System with Auto Changeover Switch and Advert Environment Employing Copula Approach}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {3}, number = {1}, pages = {17-26}, year = {2020}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/IJRRS.3.1.2}, abstract = {This paper studies the reliability measures of a system consisting of two subsystems in a series configuration for different types of failure and two types of repair. The subsystem-1 has four identical units in a parallel configuration operating under 3-out-of-4: G policy and this has connected to subsystem-2 which has three identical units arranged in a parallel configuration and working under 2-out- of-3: F, scheme. The units of subsystem-1 are controlled by a controller for preventing failure effect and safety purposes. It is assumed that units of each subsystem have different types of failure and repair rates. The unsuitability of the environmental conditions such as overheating as a well-known natural cause of failure of any system and also weather conditions like heavy rain, thunderstorm, and catastrophic shakeups, etc. have treated as a complete failure of the system. This study considers the environmental causes of failure in the proposed repairable system as complete failure by which the system stops functioning. Human failure in the system is trickled as complete failure and repair employing copula (Gumbel- Hougaard family copula distribution) like another complete failed states of subsystems. To analyze the proposed system, the supplementary variable technique are used and some measures of system reliability like availability, reliability; MTTF and incurred profit function for different values of parameters are derived. Some particular cases for different values of failure rates that have explicit are also studied.}, keywords = {Environment failure,Human failure,Availability,MTTF,Reliability,Profit analysis,Gumbel-Hougaard family copula}, url = {http://www.ijrrs.com/article_109238.html}, eprint = {http://www.ijrrs.com/article_109238_106af135fc17b2d5a41dd0455338e78b.pdf} } @article { author = {Park, Sung Hyun and Tjolleng, Amir and Park, Jeong Won and Jung, Kihyo}, title = {Detecting Unsafe Conditions of a Lathe using an Artificial Neural Network with Three-axis Acceleration Data}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {3}, number = {1}, pages = {27-34}, year = {2020}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/IJRRS.3.1.3}, abstract = {Detecting unsafe conditions of a lathe is critical to prevent hazards in a workplace. This study proposed an artificial neural network (ANN) model to classify the state of a lathe into one of the nine conditions (two normal conditions and seven unsafe conditions) based on three-axis acceleration data. The two normal conditions were (1) idle and (2) normal processing. The seven unsafe conditions included unsafe states of a lathe (i.e., eccentric rotation, chipping, improper workpiece fixation, and base looseness) and a worker (i.e., glove contact, hair contact, and necklace contact). The acceleration data for each condition were measured for 30 s using a small lathe and smoothed with the moving average. The datasets were randomly divided into three different sets for training (70%), validation (15%), and testing (15%). The ANN model was trained using the training and validation sets and its performance was evaluated using the testing set. The testing results showed that the classification accuracy of the ANN model proposed in this study (100%) was better than that of a multiclass linear support vector machine model (68%). The procedure and the ANN model established in this study can be utilized to detect unsafe conditions of a lathe and other industrial machines.}, keywords = {Artificial Neural Network,Lathe,Support Vector Machine,unsafe condition}, url = {http://www.ijrrs.com/article_109237.html}, eprint = {http://www.ijrrs.com/article_109237_8bcff38a9d44527428f3c6e8a80f95b6.pdf} } @article { author = {Poonia, Praveen and Sirohi, Anu}, title = {Cost Benefit Analysis of a k-out-of-n: G Type Warm Standby Series System Under Catastrophic Failure Using Copula Linguistics}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {3}, number = {1}, pages = {35-44}, year = {2020}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/IJRRS.3.1.4}, abstract = {This paper deals with the study of reliability measures of a complex engineering system consisting three subsystems namely L, M, and N in series configuration. The subsystem-L has three units working under 1-out-of-3: G; policy, the subsystem-M has two units working under 1-out-of-2: G policy and the subsystem-N has one unit working under 1-out-of-1: G; policy. Moreover, the system may face catastrophic failure at any time t. The failure rates of units of all subsystems are constant and assumed to follow the exponential distribution however, their repair supports two types of distribution namely general distribution and Gumbel-Hougaard family copula distribution. The system is analyzed by using the supplementary variable technique, Laplace transformation and Gumbel-Hougaard family of copula to derive the differential equations and to obtain important reliability characteristics such as availability of the system, reliability of the system, MTTF, and profit analysis. The numerical results for reliability, availability, MTTF, and profit function are obtained by taking particular values of various parameters and repair cost using maple. Tables and figures demonstrate the computed results and conclude that copula repair is more effective repair policy for better performance of repairable systems. It gives a new aspect to scientific community to adopt multi-dimension repair in form of copula. Furthermore, the results of the model are beneficial for system engineers and designers, reliability and maintenance managers.}, keywords = {k-out-of-n: G system,Availability,MTTF,Catastrophic failure,Gumbel-Hougaard family copula distribution}, url = {http://www.ijrrs.com/article_109241.html}, eprint = {http://www.ijrrs.com/article_109241_c3be6924ab5fc0e0a1096805294d25de.pdf} } @article { author = {Pourgolmohamad, Mohammad and Khayyati, Ahmad and Shiri, Saeed}, title = {Development of an Efficient Approach for Reliability Analysis Using the Comparative Study of Several Static and Dynamic Methods; Case Study of an Unmanned Aerial Vehicle}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {3}, number = {1}, pages = {45-53}, year = {2020}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/IJRRS.3.1.5}, abstract = {Unmanned Aerial Vehicles (UAV) are increasingly being popular in many applications. Their operation requires a high level of safety and reliability to accomplish successful missions. In this study, their reliability is comparatively analyzed by different available approaches to select the efficient method. Firstly, the failure model of the system is developed. Then, three different scenarios are considered to study the effect of redundancies on the reliability of the system. In the first scenario, there is no redundancy, whereas in the second scenario there is one redundant component and in the third scenario, there are three redundant components. Static reliability analysis implemented on the proposed scenarios using methods of Fault Tree Analysis (FTA), Reliability Block Diagram (RBD), Markov Chain (MC), and Bayesian Networks (BN) and the results are obtained. Also, regarding the time dependencies between redundant components, a dynamic-based methodology is developed by applying Dynamic Fault Tree (DFT) analysis. Then, the proposed static and dynamic approaches are applied to a UAV as a case study and the results are discussed. Finally, the characteristics of each methodology and the related conditions are clarified for selecting the efficient reliability analysis approach.}, keywords = {UAV,Reliability,Bayesian networks,Dynamic Fault Tree,redundancy}, url = {http://www.ijrrs.com/article_115429.html}, eprint = {http://www.ijrrs.com/article_115429_a9246097cb9855b3487846402e4310e2.pdf} } @article { author = {Labafniya, Mansourreh and Abdol, Hasan}, title = {Fault Tolerant Nanoscale Structures and Related Delay}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {3}, number = {1}, pages = {55-59}, year = {2020}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/IJRRS.3.1.6}, abstract = {Redundancy is a method in the system for designing fault tolerant structure with the Nanoscale gate in electronic systems. Until now, many ways are represented for this purpose, which increases complexity or decreases the system's reliability. In this paper, we compare two methods for designing a fault-tolerant structure with Nanoscale gates. These ways are NAND Multiplexing (NM) and Averaging Cells (AC). The results of simulation that evaluate the area cost and reliability of the gates indicates that NM based gates are more reliable than AC gates when the error probabilities of the circuit parts are lower than 0.003. However, when this value is exceeded (which is expected for electronic nanotechnologies), AC gates are more reliable at a lower area cost. In this paper, we show comparing the NM and the AC in the aspect of the delay parameter. It indicates that the AC method has a constant delay, but the NM system's delay will rise with increasing redundancy. As a result, the AC method's overhead for designing a fault-tolerant system with the Nanoscale gate is lower than the NM method in the aspect of the area and delay time with better reliability.}, keywords = {Fault-tolerance,NAND Multiplexing,Averaging Cell,delay,Reliability}, url = {http://www.ijrrs.com/article_110267.html}, eprint = {http://www.ijrrs.com/article_110267_70319dca8226ce58ff6d7fb17149ce50.pdf} } @article { author = {Karimaei, Hadiseh}, title = {Sensitive Analysis of Tuned Mass on High Cycle Fatigue Safety Factor of Crankshaft}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {3}, number = {1}, pages = {61-67}, year = {2020}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/IJRRS.3.1.7}, abstract = {Torsional vibration (TV) is one of the major issues and very important calculation for the safe running of internal combustion engines, specifically crankshaft. The properties of parts connected to the crankshaft have significant effect on vibration of the system as well as the crankshaft life. Initial selection of this part is usually specified based on engine designer experience and also the torsional vibration calculation of the crank train. In this paper, the focus is to find optimum tuned mass to connect to the crankshaft from the damper side using CAE tools. It is a mounting disk at the free end of the crankshaft named tuned mass. Therefore, the effect of tuned mass inertia on design criteria, especially crankshaft life, was investigated. The results show high sensitivity of high cycle fatigue safety factor of crankshaft to tuned mass. Therefore, adding a suitable tuned mass to the system can increase the crankshaft life, when needed. The results were presented in the paper in detail.}, keywords = {Classical Torsional vibration,Cranktrain,Tuned mass,High Cycle Fatigue,Crankshaft life}, url = {http://www.ijrrs.com/article_119377.html}, eprint = {http://www.ijrrs.com/article_119377_e5efeb20ca78943b26baa825cb52e6d4.pdf} } @article { author = {Bazeli, Shakiba and Fallahnezhad, Mohammad Saber}, title = {Clustering of Condition-Based Maintenance Considering Perfect and Imperfect actions}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {3}, number = {1}, pages = {69-76}, year = {2020}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/IJRRS.3.1.8}, abstract = {Recent developments in condition monitoring technology have delivered important opportunities for condition-based maintenance. Although condition-based maintenance allows for more effectively planned maintenance actions, its relative performance depends on the behavior of the deterioration process. The objective of this paper is to develop a clustering model of maintenance activities and analyze the effect of perfect, imperfect, and hybrid maintenance on the cost. We consider a two-component system that experiences three degradation states before a complete failure. The components are equipped with a monitoring system that signals before each state change, on which our clustering is based. Actually, we have three types of clustering aiming at cost minimization. The results provide a general insight into when and how the activities are clustered and what kind of maintenance is selected such that the cost is minimized. Moreover, The results showed that clustering with a more degree of the clusters is more appropriate and produced cost savings about 70%, if the fixed cost exceeds a certain amount.}, keywords = {Imperfect maintenance,Condition-based Maintenance,Clustering,Condition Monitoring,Prediction signal}, url = {http://www.ijrrs.com/article_119346.html}, eprint = {http://www.ijrrs.com/article_119346_07fcdf0a1d293bbbc235276d3fdc0968.pdf} } @article { author = {Nadjafi, Mohammad and Gholami, Peyman}, title = {Bayesian Inference of Reliability Growth-Oriented Weibull Distribution for Multiple Mechanical Stages Systems}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {3}, number = {1}, pages = {77-84}, year = {2020}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/IJRRS.3.1.9}, abstract = {The Duane and Crow-AMSAA reliability growth model has been traditionally used to model systems and products undergoing development testing. The Non-Homogeneous Poisson Process (NHPP) with a power intensity law has been often used as a model for describing the failure pattern of the repairable systems and the maximum likelihood (ML) estimates are used to calculate the unknown parameters widely. This study proposes the statistical analysis method of different stages and different level data based on Bayes analysis techniques. To this end, the Bayesian reliability growth model of multiple stages is coupled with the Weibull distribution product. By using the unique properties of the assumed prior distributions, the moments of the posterior distribution of the failure rate at various stages during a development test can be found. In this paper, it is assumed that the scale parameter has a Gamma prior density function, and the growth parameter has a Uniform prior distribution. Monte Carlo simulations are used to compute the Bayes estimates. Finally, the results obtained from the proposed method by implementing it on an application example are compared with Crow-AMSAA data and show that the proposed model has higher accuracy than the existing traditional methods.}, keywords = {reliability growth,Non-homogeneous Poisson process (NHPP),Bayes Analysis,Weibull distribution,Monte Carlo}, url = {http://www.ijrrs.com/article_119347.html}, eprint = {http://www.ijrrs.com/article_119347_446f802257d119ef9c3c4a599548d0fc.pdf} } @article { author = {Jadidi, Nasim and Bazdar, Ali Asghar}, title = {Safety Risk Management in Production Process: A case study in the automotive supplier industry}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {3}, number = {1}, pages = {85-95}, year = {2020}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/IJRRS.3.1.10}, abstract = {This paper deals with the study of reliability measures of a complex engineering system consisting three subsystems namely L, M, and N in series configuration. The subsystem-L has three units working under 1-out-of-3: G; policy, the subsystem-M has two units working under 1-out-of-2: G policy and the subsystem-N has one unit working under 1-out-of-1: G; policy. Moreover, the system may face catastrophic failure at any time t. The failure rates of units of all subsystems are constant and assumed to follow the exponential distribution however, their repair supports two types of distribution namely general distribution and Gumbel-Hougaard family copula distribution. The system is analyzed by using the supplementary variable technique, Laplace transformation and Gumbel-Hougaard family of copula to derive the differential equations and to obtain important reliability characteristics such as availability of the system, reliability of the system, MTTF, and profit analysis. The numerical results for reliability, availability, MTTF, and profit function are obtained by taking particular values of various parameters and repair cost using maple. Tables and figures demonstrate the computed results and conclude that copula repair is more effective repair policy for better performance of repairable systems. It gives a new aspect to scientific community to adopt multi-dimension repair in form of copula. Furthermore, the results of the model are beneficial for system engineers and designers, reliability and maintenance managers.}, keywords = {K-out-of-n,G system,Availability,MTTF,Catastrophic failure,Gumbel-Hougaard family copula distribution}, url = {http://www.ijrrs.com/article_117690.html}, eprint = {http://www.ijrrs.com/article_117690_52a7094b56d88708b2cb0cc18403a239.pdf} } @article { author = {Habibirad, Arezou and kazempoor, Jaber}, title = {The Conditional Estimation for related Weibull parameters Under Type-II Censoring}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {3}, number = {1}, pages = {97-101}, year = {2020}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/IJRRS.3.1.11}, abstract = {In this paper, the conditional estimation of the Weibull and its related parameters are introduced. Some interesting properties of this estimator in contrast with the well-known maximum likelihood estimators have been investigated. This task is done under the famous sampling plan type-ii censoring scheme. Because of the complex behavior in the calculation of the likelihood function of the presented scheme in this situation without loss of generality, this problem fixed with the Gumbel (log-Weibull) model. The one to one transformation between these models and satisfying in their parameters enabling us for utilizing this alternative model. Finally, the comparison of this method and maximum likelihood estimation are provided through some numerical results.}, keywords = {Conditional estimation,Gumbel distribution,Weibull mode}, url = {http://www.ijrrs.com/article_109236.html}, eprint = {http://www.ijrrs.com/article_109236_562037d83206b9896c122266a255631d.pdf} } @article { author = {Yusuf, Ibrahim and Sani, Baffa and Umar, Surajo}, title = {Reliability Enhancement of Computer Network System with Server Replication}, journal = {International Journal of Reliability, Risk and Safety: Theory and Application}, volume = {3}, number = {1}, pages = {103-112}, year = {2020}, publisher = {Aerospace Research Institute, Ministry of Science, Research and Technology, IRAN}, issn = {2676-3346}, eissn = {2676-3346}, doi = {10.30699/IJRRS.3.1.12}, abstract = {Reliability is a performance factor applied to multi-computer network system consisting of devices such as active parallel or redundant hosts (clients), distributed database servers with replication, anda central server. For reliability evaluation and performance of such a system, this study analyzed a computer network system consisting of hosts (clients) connected to two distributed database servers in replication to each other. The system is configured as a series-parallel system consisting of two subsystems, namely A and B. Subsystem A consists of three clients in active parallel while subsystem B consists od two distributed database servers in replication to each order. Both clients and server failure and repair time are to be exponentially distributed The system is analyzed using first-order differential-difference equations to derive the expressions for the availability, mean time to failure, probability of a busy period of repairman due to partial or complete failure. The results are presented in tables and graphs. Reliability characteristics such as availability, MTTF, profit function as well as sensitivity analysis have been discussed. The computed results are demonstrated by tables and graphs. From the analysis of reliability characteristics, it is evident that availability,   profit , and mean time to failure can be enhanced by adding more servers in replication to each other.}, keywords = {Availability,Mean time to failure,network,Reliability}, url = {http://www.ijrrs.com/article_115430.html}, eprint = {http://www.ijrrs.com/article_115430_935753243ab428ba15bc041aa8277240.pdf} }