Research on Reliability Analysis Method of UHP Liquid Pump Based on Degradation Simulation Algorithm

Aiming at the limitation of traditional trans-scale safety and arming device reliability analysis method, this paper presents a reliability calculation method for trans-scale safety and arming device about failure mechanism, failure process and failure mode correlation. The problem which the trans-scale safety and arming device is easy to be affected by technology, structure, gap, material and so on, the failure mechanism is complex, the reliability data is short and the reliability is difficult to predict is solved. This article estimates the system reliability of (the reliability is 0.992725), analyzes the key failure modes and influencing parameters that affect system reliability, and establishes an optimization design model based on the key reliability impact parameters, which improves the system reliability index (reliability is 0.99905) and verifies the accuracy and rationality of the reliability analysis method.

Fairing separation is an important action in rocket or missile flight process, the ability to achieve safe separation is one of the key factors which decide the success of launch. For the high cost of fairing separation exercise test, the test environment is difficult to simulate and the test samples are limited, reliability analysis based-simulation method for payload fairing separation is proposed. Considering the law motion and working conditions of the low-altitude high-speed payload fairing, the separation system's main failure modes and failure criteria are proposed, its simulation model by Aided 3D modeling software, the aerodynamic calculation software, finite element software and multi-body analysis software is established. In order to get fairing separation mission's reliability, each failure modes during separation process is analyzed combining with classic reliability analysis methods. Finally, one example demonstrates that it is feasible and practical to analyze separation system's failure mechanism and failure mode by utilizing simulation technology combining with reliability analysis methods.

In this paper, a new method is developed that can be applied efficiently in reliability analysis and design verification of structures under random vibration. This method is based on singular value decomposition of modal coordinates cross covariance matrix. Computational algorithm and relative flow chart for this method is developed and compatible reliability criterion with this algorithm has been extracted. In order to results verification, we use Miles relation and Monte Carlo simulation -that are two well known methods in reliability analysis- and all of these methods are applied to a simple finite element model. Results show that new algorithm is more efficient for reliability analysis of structures under random vibration.

This paper reviews three main methods in reliability analysis for power systems and applies them to a micro-grid with significant clean energy penetration. The approaches used are Reliability Block Diagrams (RBD), Fault Tree Analysis (FTA) and Markov Reliability Modeling (MRM). Each method is introduced and applied to a simple system to illustrate its application procedure. Reliability parameters such as the system's mean time to failure (MTTF), component structure importance, and reliability function are evaluated using simulation models. All three methods are then used to find the reliability measures of a real micro-grid which is characterized by significant clean energy penetration using solar photovoltaic panels and a fuel cell.

A new unequal-weighted sampling method for efficient reliability analysis

The probability of failure free software operation for a specified period of time in a specified environment is called Reliability, it is one of the attributes of software quality and study about it come back to 1384. Exposition and spreading of new software systems and profound effect of it to human life emphasize the importance of software reliability analysis, until it poses formal definition at 1975. First race of reliability analysis methods that we called classic methods has stochastic process approach and in this way, attempt to predict the software behavior in future. Due to the ambiguity in fruitfulness of these solutions the challenge about reliability analysis continued till now. Great tendency in applying intelligence systems at variety of applications can be seen at 90 decade, and software reliability attracts some research direction to itself. Until now variety of methods in reliability analysis on the base of intelligence systems approach exhibited. In this survey the taxonomy of these methods represented with brief description of each one. Also comparison between these methods can be seen at the end of survey.

PurposeAs a clean and renewable energy source, wind energy will become one of the main sources of new energy supply in the future. Relying on the stable and strong wind resources at sea, wind energy has great potential to become the primary energy. As a critical part of the wind turbine, the gearbox of a wind turbine often bears a large external load. Especially at sea, due to the effects of ocean corrosion, waves and wind, the burden of the wind turbine gearbox is greater, which brings great challenges to its reliability analysis. This study aims to systematically review the reliability research in wind turbine gearboxes and guide future research directions and challenges.Design/methodology/approachThis study systematically reviews some design requirements and reliability analysis methods for wind turbine gearboxes. Then, it summarizes previous studies on wind load uncertainty modeling methods, including the processing of wind measurement data and the summary of three different classifications of random wind speed prediction models. Finally, existing reliability analysis studies on two major parts of the gearbox are described and summarized.FindingsFirst, the basic knowledge of wind turbine gearboxes and their reliability analysis is introduced. The requirements and reliability analysis methods of wind turbine gearboxes are explained. Then, the processing methods of wind measurement data and three different random wind speed prediction models are described in detail. Furthermore, existing reliability analysis studies on two common parts of wind turbine gearboxes, gears and bearings, are summarized and classified, including a summary of bearing failure modes. Finally, three possible future research directions for wind turbine gearbox reliability analysis are discussed, namely, reliability research under the influence of multiple factors on gears, damage indicators of bearing failure modes and quantitative evaluation criteria for the overall dynamic characteristics of offshore wind turbine gearboxes and a summary is also given.Originality/valueThis paper aims to systematically introduce the relevant contents of wind turbine gearboxes and their reliability analysis. The contents of wind speed data processing, predictive modeling and reliability analysis of major components are also comprehensively reviewed, including the classification and principle introduction of these contents.

Fuzzy reliability analysis can be implemented using two discrete optimization maps in the processes of reliability and fuzzy analysis. Actually, the efficiency and robustness of the iterative reliability methods are two main factors in the fuzzy-based reliability analysis due to the huge computational burdens and unstable results. In the structural fuzzy reliability analysis, the first-order reliability method (FORM) using discrete nonlinear map can provide a C membership function. In this paper, a discrete nonlinear conjugate map is proposed using a relaxed-finite step size method for fuzzy structural reliability analysis, namely Fuzzy conjugate relaxed-finite step size method fuzzy CRS. A discrete conjugate map is stabilized using two adaptive factors to compute the relaxed factor and step size in FORM. The framework of the proposed fuzzy structural reliability method is established using two linked iterative discrete maps as an outer loop, which constructs the membership function of the response using alpha level set optimization based on genetic operator, and the inner loop, implemented for reliability analysis using proposed conjugate relaxed-finite step size method. The fuzzy CRS and fuzzy HL-RF methods are compared to evaluate the membership functions of five structural problems with highly nonlinear limit state functions. Results demonstrated that the fuzzy CRS method is computationally more efficient and is strongly more robust than the HL-RF for fuzzy-based reliability analysis of the nonlinear structural reliability problems.

In recent years, time‐variant reliability issues have garnered widespread attention, particularly due to their consideration of the cumulative effects of material degradation and the time dependency of stochastic process loads. Methods based on the outcrossing rate are typically employed for time‐variant reliability analysis. However, they fail to effectively capture the correlations among multiple failure modes. To address this limitation, this paper proposes a time‐variant reliability analysis method that accounts for the correlation of multiple failure modes by integrating copula and PHI2. The method first utilizes Copula to analyze the correlations among various failure modes, followed by applying the PHI2 method for the time‐dependent reliability analysis of each individual failure mode. Ultimately, case studies confirm that the proposed method proficiently evaluates the time‐variant reliability of systems with multiple failure modes, yielding a maximum relative error below 5% compared to MCS and significant performance enhancements.

This paper demonstrates how the ISO/TC67/WG4 standards portfolio, and in particular ISO 20815, can be used to support decision- making for sustainable technology development for oil and gas and lower-carbon energy. The paper also outlines the business value of applying these standards in industry and to energy transition activities. ISO/TC67/WG4 is responsible for developing reliability and cost related standards for the oil and gas industry, including lower-carbon energy. This paper presents the ISO 20815 standardized approach for the production assurance and reliability management needed to support energy transition within the subsea and electrification domains. Operators are undertaking technology development that relocates traditionally topside systems to the seafloor to reduce costs and risks. The concept of a subsea chemical storage and injection system (SCSIS) versus a traditional topside system was assessed. Special performance measures for comparison purposes were addressed. System availability and production availability of offshore and onshore facilities affected by electrification, in terms of power supply and configuration of processing and utility functions, will also benefit from the use of production assurance and reliability management. To support the technology development process for the SCSIS concept, a comparative availability analysis of the topside versus subsea concept was undertaken in conformance with ISO 20815 and ISO 14224. This analysis provided conclusions and recommendations that supported the technology development process. The analysis demonstrated successful use of the reliability technology methodology outlined in ISO 20815 and ISO 14224 and how this methodology is key to understanding technological risk. Reliability and availability analyses enabled differentiation of technical and operational factors and alternative operating and maintenance strategies and potential system design changes aimed at improving performance. Brownfield projects associated with the electrification of onshore facilities can derive significant benefits from equipment reliability and system availability analysis using ISO 20815. The paper illustrates how the implementation of the standards in the ISO/TC67/WG4 portfolio can support decision-making during technology and project development processes. Furthermore, it provides general awareness of the standards that have the potential to underpin the industry's ability to overcome present and future challenges. The third edition of ISO 20815 is currently under development, and this paper will provide examples of how ISO 20815 can be used to compare traditional and new subsea technology. The use of ISO 20815 to assess offshore electrification availability can help operators select affordable energy transition solutions. The paper will also provide insights into the use of reliability and availability analysis methods and techniques for different life cycle phases.

Engineering fuzzy heat conduction problem with subjective uncertainties in input parameters constitutes a significant challenge. Based on fuzzy and interval theory, this paper presents novel numerical methods to efficiently identify the effect of fuzzy uncertainty on the system reliability analysis and optimization design. Firstly using the interval ranking strategy, the interval safety possibility in the transition state can be precisely quantified, and the eventual fuzzy safety possibility is calculated by integral operation. Then a fuzzy reliability-based optimization model is established with considerable computational cost caused by the two-layer nested loop. In order to improve the computational efficiency, a subinterval perturbation method based on the first-order Taylor series is presented to replace the inner loop. Comparing numerical results with traditional reliability model, two numerical examples are provided to evidence the superiority of proposed model and method for fuzzy reliability analysis and optimization in practical engineering.

Mechanism reliability includes structural reliability of mechanism components and kinematic reliability of the mechanism. In fact, in practice mechanism reliability usually considers only kinematic reliability of the mechanism. Strength degradation including fatigue, wear, corrosion, and motion error, etc., are major failure mechanism of systems, sub-systems or components. In this paper, it is based on mechanism synthesis. In addition, the paper considers time dependence of strength degradation and fuzziness of the state in mechanism reliability analysis. Strength degradation mainly includes motion error and wear. Fuzzy time-dependent mathematical model of reliability is established based on fuzzy time-dependent methods, such as PHI2\MCS, and combined with traditional mechanical reliability analysis methods, such as FORM\SORM. The paper considers fuzziness of the state at the same time. Thus, fuzzy time-dependent failure probability is able to compute. Two examples demonstrate the practicality and feasibility of the method.

Although an accurate reliability assessment is essential to build a resilient infrastructure, it usually requires time-consuming computation. To reduce the computational burden, machine learning-based surrogate models have been used extensively to predict the probability of failure for structural designs. Nevertheless, the surrogate model still needs to compute and assess a certain number of training samples to achieve sufficient prediction accuracy. This paper proposes a new surrogate method for reliability analysis called Adaptive Hyperball Kriging Reliability Analysis (AHKRA). The AHKRA method revolves around using a hyperball-based sampling region. The radius of the hyperball represents the precision of reliability analysis. It is iteratively adjusted based on the number of samples required to evaluate the probability of failure with a target coefficient of variation. AHKRA adopts samples in a hyperball instead of an n-sigma rule-based sampling region to avoid the curse of dimensionality. The application of AHKRA in ten mathematical and two practical cases verifies its accuracy, efficiency, and robustness as it outperforms previous Kriging-based methods.

Reliability analysis based on a novel density estimation method for structures with correlations

Reliability analysis method based on determination of the performance function’s PDF using the univariate dimension reduction method