International Journal of Reliability and Safety (6 papers in press)

Regular Issues

• Pre-chamber spark ignition: a reliability analysis of pre-chamber valve functions  
  by Faraz Akbar, Sarah Zaki 
  Abstract: A pre-chamber ignition allows spark-ignition engines to operate in lean air-fuel settings. It improves fuel efficiency and reduces emissions. In this study, a reliability analysis of a single GE Jenbacher J620 natural gas engine was done. It was operational on continuous load in the power generation sector in Karachi, Pakistan. A bathtub curve of the GE J620 pre-chamber gas valve (PCV) was generated. The three-year industrial data comprised PCV failures that occurred between two overhauls. During infant mortality, the curve revealed 7 failures during 1000 hours. This decreased to a failure for the next two cycles of thousand hours each. There was a 40% decrease in reliability after 1500 hours. Exponential distribution revealed that the mean time-to-failure (MTTF) was 545.5 hours. This study was the first of its kind in the facility. Previously, much time was lost in breakdown maintenance. Thus, it helped to increase the systems reliability.
  Keywords: bathtub curve; exponential distribution; failure rate; fuel injection; gas engine; pre-chamber combustion; pre-chamber spark ignition; pre-chamber valve; probability density function; reliability.
  
  
• A comparative study of M5P, ANN, and RENB models for prediction of vulnerable road accident frequency  
  by Saurabh Jaglan, Praveen Aggarwal, Sunita Kumari 
  Abstract: The present investigation aims to evaluate the performance of different models to calculate the vulnerable road user accident frequency (VRUAF). Nine different road stretches were chosen to measure the road geometry and other similar characteristics. Field studies were conducted to gather information about road geometry, traffic surveys, and accident characteristics. A total 17 number of input parameters were collected for accident frequency analysis, and three prediction approaches were applied: Fixed/Random Effect Negative Binomial (FENB/RENB) regression models, Artificial Neural Network (ANN), and M5P model tree. The variation in models' performance was observed in terms of the coefficient of correlation (0.943-0.981), root mean square error (2.274-1.655), and mean absolute error (1.746-1.351). The result suggests that the ANN model is the most accurate model where values of CC, MAE, and RMSE vary from 0.981,1.351 and 1.655, respectively. Thus, this model can predict VRUAF without accident data under similar geometric conditions synthetically.
  Keywords: vulnerable road user; accident frequency; artificial neural network; random effect negative binomial model; M5P model tree.
  DOI: 10.1504/IJRS.2024.10061554
   
  
• Influence of safety culture on Chinese oversea hydropower project workers safety performance: a case study in Cameroon  
  by Bouba Oumarou Aboubakar, Hongxia Li 
  Abstract: This paper attempts to evaluate the influence of safety culture on the safety performance of Chinese international hydropower projects in Cameroon. It addresses the intrinsic influence of external hazards management, National culture, workers safety knowledge and attitudes, Chinese managers’ commitment on safety behaviors and motivation using a Structural model analyzed by Lisrel. The data were collected via questionnaires from 566 workers in hydropower projects in Cameroon. The results revealed that (1) External hazards management positively influence safety motivation of both Chinese and local workers, but does not have a significant influence on their safety behaviors;(2)National culture sharing positively influences safety behaviors and safety motivation of workers;(3)It was established that workers safety knowledge slightly positively influences safety behavior but not the safety motivation of workers;(4)Workers safety attitude positively influences safety behaviors;(5)higher safety commitment from Chinese management were associated with higher positive safety behavior and safety motivation of workers. In the end, theoretical as well as useful implications were proposed and suggestions for future work were also given based on the results in this study.
  Keywords: safety culture; safety performance; hydropower projects; structural equation modelling; Chinese contractors.
  DOI: 10.1504/IJRS.2024.10063286
   
  
• Reliability analysis of three state linear consecutive 2-out-of-4:F system by continuous time Markov model  
  by J. Madhumitha, G. Vijayalakshmi 
  Abstract: In this paper, the continuous time Markov model for the L(cons/2-4:F) system is described. Each component of the system has three states (good state, degraded state, and failed state). The failure and repair times follow an exponential distribution. The dependability measures such as availability and reliability are obtained. The effect of failure and repair rates on system availability and system reliability are presented. The mathematical consequences of the reliability measures will be of incredible assistance to the system engineers and decision-makers in improving and future designing the system. The proposed system can be used in nuclear power plants and telecommunication systems.
  Keywords: linear consecutive 2-out-of-4:F system; continuous time Markov model; multi-state system; reliability; availability.
  DOI: 10.1504/IJRS.2024.10064125
   
  
• Human-caused accident evaluation of coal mine safety relying on ant colony clustering algorithm  
  by Wenzhe Lai 
  Abstract: Through the analysis of numerous case samples, it is easy to find that the numerous reasons for the frequent occurrence of coal mine accidents are all human factors, and human-caused accidents have become the main cause of coal mine safety The causes of human-caused accidents are very complex, and the characteristic mechanisms of accidents are difficult to extract and carry out accurate data measurement, so the traditional engineering safety measurement methods have great limitations and cannot accurately evaluate the causes of human-caused accidents in coal mines in the problem of high-dimensional pattern recognition Based on this, the main work of the study focused on: selecting the algorithm with good performance of simulated evolution-ant colony clustering algorithm as the technical support for the evaluation work, combining with the current mine production practice, four categories of factors from individual worker factors, environmental factors, life event factors and biological rhythm factors were clustered
  Keywords: ant colony clustering knowledge recognition algorithm; coal mine safety; human accidents; individual factors.
  DOI: 10.1504/IJRS.2024.10064200
   
  
• Fuzzy fault tree analysis method of denitration system in thermal power plant  
  by Xiong Wei, Teng Wang, Xu Wang, Jiajun Ma, Guangjie Li, Qiang Zhan, Dandan Wu, Jiancun Zuo 
  Abstract: Denitration system (DS) is an important part of the production of thermal power plants, and any failure that occurs during its operation will seriously affect the productivity and safety of thermal power plants. Therefore, this paper proposes a fuzzy fault tree (FFT) analysis method for DS of thermal power plant. Firstly, the theory of FFT is described, then the process flow of DS is introduced, the main faults in the operation of the system are analysed, and the FFT is established for the main faults. The ambiguity of the basic event probability is solved by fuzzy set theory and expert judgement. After qualitative and quantitative analysis, the weak parts of the system and the degree of importance of the basic events are evaluated, so that it is of great significance to formulate protective measures in advance for the weak links of the system.
  Keywords: fuzzy fault tree; denitration system of thermal power plant; fuzzy number; language variables; expert evaluation; industrial safety.
  DOI: 10.1504/IJRS.2024.10064874