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A study of the Inverse Gaussian Process with hazard rate functions-based drifts applied to degradation modellingDOI: 10.17531/ein.2022.3.20 Issue: Article citation info: Rodríguez-Picón LA, Méndez-González LC, Pérez-Olguín IJC, Hernández-Hernández JI. A study of the Inverse Gaussian Process with hazard rate functions-based drifts applied to degradation modelling. Eksploatacja i Niezawodnosc – Maintenance and Reliability 2022; 24 (3): 590–602, http://doi.org/10.17531/ein.2022.3.20.
Abstract: The stochastic modelling of degradation processes requires different characteristics to be considered, such that it is possible to capture all the possible information about a phenomenon under study. An important characteristic is what is known as the drift in some stochastic processes; specifically, the drift allows to obtain information about the growth degradation rate of the characteristic of interest. In some phenomenon’s the growth rate cannot be considered as a constant parameter, which means that the rate may vary from trajectory to trajectory. Given this, it is important to study alternative strategies that allow to model this variation in the drift. In this paper, several hazard rate functions are integrated in the inverse Gaussian process to describe its drift in the aims of individually characterize degradation trajectories. The proposed modelling scheme is illustrated in two case studies, from which the best fitting model is selected via information criteria, a discussion of the flexibility of the proposed models is provided according to the obtained results. |
Experimental testing of the influence of the operating loading on the flow characteristics of hydraulic pumpDOI: 10.17531/ein.2022.3.19 Issue: Article citation info: Kosiba J, Tkáč Z, Jablonický J, Shcherbak V, Ganushchak-Yefimenko L, Paumer M, Bukoros T, Čurgaliová G, Zachar M. Experimental testing of the influence of the operating loading on the flow characteristics of hydraulic pump. Eksploatacja i Niezawodnosc – Maintenance and Reliability 2022; 24 (3): 583–589, http://doi.org/10.17531/ein.2022.3.19.
Abstract: The contribution deals with the influence of the operating loading on the flow characteristics of the hydraulic pump under laboratory conditions. In the test, a new toothed hydraulic pump and hydraulic oil with kinematic viscosity at 40°C, ν = 64.2 mm2.s-1 were used. The operational loading was measured during the most difficult agrotechnical operation – ploughing, at which the loading of the hydraulic pump is the greatest. Laboratory testing was determined for 200 hours, and the flow characteristics had been detected at 50 hours intervals. Measurement of the flow characteristics was performed at rated speed n = 1,000 rpm. Measurement of the flow characteristics was carried out in dependence on the loading pressure from p = 0 MPa to p = 20 MPa. When p = 0 MPa, the value reached n = 91.70% and when p = 20 MPa, n = 86.68%. Running-in of the hydraulic pump lasted 150 hours, with an increase of the flow characteristics Δηvol = 1.36% (p = 10 MPa) compared to the initial state. After working for 200 hours, the flow rate of the hydraulic pump decreases compared to 150 hours. |
Research on reliability allocation strategy for gear transmission system of high-speed trainDOI: 10.17531/ein.2022.3.18 Issue: Article citation info: Ai Y, Cui P, Li Y, Zhang W. Research on reliability allocation strategy for gear transmission system of high-speed train. Eksploatacja i Niezawodnosc – Maintenance and Reliability 2022; 24 (3): 574–582, http://doi.org/10.17531/ein.2022.3.18.
Abstract: High-speed train industry is in the stage of rapid development, and the reliability allocation strategy is helpful to improve the reliability of the system and reduce the economic cost of components. In this paper, the reliability allocation of gearbox transmission system of highspeed train is studied. Combining AGREE allocation method and reliability allocation method based on cost function, the reliability allocation of high-speed train gear transmission system is carried out. Considering the quantity, importance, cost and complexity of various parts of high-speed train gear transmission system, the feasibility factor of improving reliability based on the cost function allocation method was improved to acquire the improved cost function, and the reliability optimization allocation model based on the improved cost function was established. Compared with AGREE allocation method and the traditional allocation method based on cost function, the improved optimization allocation strategy proposed in this paper is more suitable for high-speed train gear transmission system. |
A method for obtaining the preventive maintenance interval in the absence of failure time dataDOI: 10.17531/ein.2022.3.17 Issue: Article citation info: Sánchez-Herguedas A, Mena-Nieto A, Rodrigo-Muñoz F. A method for obtaining the preventive maintenance interval in the absence of failure time data. Eksploatacja i Niezawodnosc – Maintenance and Reliability 2022; 24 (3): 564–573, http://doi.org/10.17531/ein.2022.3.17.
Abstract: One of the ways to reduce greenhouse gas emissions and other polluting gases caused by ships is to improve their maintenance operations through their life cycle. The maintenance manager usually does not modify the preventive intervals that the equipment manufacturer has designed to reduce the failure. Conditions of use and maintenance often change from design conditions. In these cases, continuing using the manufacturer's preventive intervals can lead to non-optimal management situations. This article proposes a new method to calculate the preventive interval when the hours of failure of the assets are unavailable. Two scenarios were created to test the effectiveness and usefulness of this new method, one without the failure hours and the other with the failure hours corresponding to a bypass valve installed in the engine of a maritime transport surveillance vessel. In an easy and fast way, the proposed method allows the maintenance manager to calculate the preventive interval of equipment that does not have installed an instrument for measuring operating hours installed. |
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