Fatigue Damage Prediction as a Part of Technical Systems Reliability Assessment

2017 ◽  
Vol 755 ◽  
pp. 131-138 ◽  
Author(s):  
Bohuš Leitner ◽  
Mária Lusková ◽  
Zdeněk Dvořák ◽  
Eva Sventekova
Keyword(s):  
Fatigue Damage ◽  
Operating Conditions ◽  
Practical Application ◽  
Civil Structures ◽  
Damage Prediction ◽  
Damage Level ◽  
Material Fatigue ◽  
Boundary States ◽  
Technical Systems ◽  
Damage Processes

Material fatigue of different technical systems parts belongs to the most frequent causes of boundary states occurrence and relating operation breakdowns. An extraordinary attention is dedicated to the prediction of fatigue damage processes in structures elements all over the world because breakdowns, caused by a fatigue failure, have often a character of catastrophe. There should be a dominant effort to bring conditions of calculation or experimental measures near to the working conditions in which the investigated system is exploited. A modern way of calculation of any technical systems (e.g. large mechanical or civil structures) therefore demands to respect dynamic and stochastic nature of all influencing working factors and related working loads. The main reason for it is prevention from their working breakdowns. The objective of the paper is general formulation of reliability of technical systems assessment, brief characteristic of basic areas to be taken into account as input into calculated prediction of technical systems fatigue damage level and analysis of risk items by its practical application in real operating conditions.

Analysis of risk concept for technical systems using digital twins

2020 ◽  
pp. 99-113
Author(s):  
Анатолий Михайлович Лепихин ◽  
Николай Андреевич Махутов ◽  
Юрий Иванович Шокин ◽  
Андрей Васильевич Юрченко
Keyword(s):  
Risk Management ◽  
Risk Analysis ◽  
Risk Model ◽  
Computer Modelling ◽  
Product Lifecycle Management ◽  
Operating Conditions ◽  
Digital Twins ◽  
Real Objects ◽  
Technical Systems ◽  
Active Research

Рассмотрены основные методологические аспекты анализа рисков технических систем с использованием цифровых двойников. Сформулирована концепция рисканализа и предложена базовая модель для ее реализации. Рассмотрены информационные аспекты анализа неопределенностей модели риска. Показано, что технологии цифровых двойников позволяют эффективно сочетать результаты компьютерного моделирования с данными мониторинга реальных объектов, обеспечивая более глубокий анализ объектов, с учетом множества вариантов конструкции, технологий и условий эксплуатации Development of technology and technical systems significantly increases in the volume of information. Traditional methods for designing, manufacturing and operating of technical systems do not allow processing such volumes of information. In this regard, the modern strategy for creating technical systems is based on the use of digital twins. Solving the problems of risk analysis and risk management for technical systems at all stages of the life cycle appears to be one of the promising areas for application of the digital twins technology. Despite of active research, using digital twins in risk analysis currently do not have appropriate methodological justifications and technical solutions in a number of key aspects. In particular, effective reductions of the order of risk models and quantifying uncertainty factors of various types have not been solved. The concept of the risk-informed decision making in product lifecycle management has not been implemented. In fact, there are very few publications on the risk analysis and risk management methodology using digital twins. The article discusses the main methodological aspects of risk analysis of technical systems using digital twins. The concept of risk analysis is formulated and a basic model for its implementation is proposed. The informational aspects of the analysis of uncertainties of the risk model are considered. It is shown that digital twin technologies allow effective combination of the results of computer modelling with the data monitoring of real objects, providing a deeper analysis of objects, taking into account a variety of design options, technologies and operating conditions.

Analysis of Fatigue Mechanical Behaviors of Welding Conformations in Orthotropic Steel Bridge Deck

2015 ◽  
Vol 1096 ◽  
pp. 562-566 ◽  
Author(s):  
Bo Yu ◽  
Tao Hong ◽  
Jian Zhang ◽  
Qing Yu Liang
Keyword(s):  
Fatigue Damage ◽  
Bridge Deck ◽  
Fatigue Tests ◽  
Steel Bridge ◽  
Test Results ◽  
Practical Application ◽  
Mechanical Behaviors ◽  
Homogeneous Test ◽  
Orthotropic Steel Bridge Deck ◽  
Damage Theory

Due to the superior structure style, orthotropic steel bridge deck has been getting more and more widely practical application. The static and fatigue tests of the orthotropic steel bridge deck models were carried out in this research paper, which presented the fatigue damage developing laws, compared the test results with homogeneous test results in existing documents, and according to the relative fatigue accumulative damage theory, the fatigue accumulative damage equations of the sectional specimen and the whole specimen are respectively studied.

scholarly journals THE MAIN TEST RESULTS OF THE MI-2MSB HELICOPTER EQUIPPED WITH THE EXPERIMENTAL SYSTEM OF SMALL ARMS AND SERIES-PRODUCED SYSTEM OF UNGUIDED MISSILE ARMAMENT

2020 ◽  
pp. 26-32
Author(s):  
A. Berezniak ◽  
Т. Dudnik ◽  
O. Zakutko
Keyword(s):  
Experimental System ◽  
Operating Conditions ◽  
Test Results ◽  
Practical Application ◽  
Flight Crew ◽  
Small Arms ◽  
Functional Capabilities ◽  
Actual Volume ◽  
Type C ◽  
Missile System

The summarized results of special tests of the Mi-2MSB helicopter equipped with the experimental system of 12,7 mm small arms (as a part with series-produced machine guns NSVT-12,7) and the serial system of unguided missile armament (NAR type C-8) are presented. The actual volume of assessments of inspections and work performed during the tests is given. According to the results of processing the test materials, it was determined that the tactical range of the Mi-2MSB helicopter with the installed weapons system and boxes for collecting spent units (in the design provided for testing) at a takeoff mass of 3700 kg, at an altitude of not more than 300 m during combat mission in the area of the target for 5 minutes and the remaining fuel on the landing of 100 liters is (not less): version of combat equipment 2 × B8V8MSB (payload - 16 NAR) - 190 km; version of combat equipment 2 × NSVT-12.7 (payload - 600 rounds) - 200 km; version of combat equipment 2 × B8V8MSB + 2 × NSVT-12.7 (payload - 16 NAR and 600 rounds) - 155 The results of special tests practically showed that the Mi-2MSB helicopter, equipped with an aviation weapon system, in addition to the functional tasks defined for the basic Mi-2MSB helicopter, is able to provide: training and maintenance of skills for flight crew in the practical application of unguided aviation weapons and gun armaments in all types of maneuvering, defined by the tactics of army aviation; accomplishment of certain tasks on air support of columns of troops on the march and fire missions on destruction of enemy manpower, single unarmored and lightly armored targets such as car, armored personnel carrier, infantry fighting vehicle, boat, The main combat and functional capabilities in the actual operating conditions confirmed by the results of special tests as well as their validation of specified requirements make it possible (after eliminating the shortcomings identified in the test), to allow operation of Mi-2MSB helicopter in the entire operating range of heights and speeds equipped with aircraft weapons as part of the unguided missile system (NAR type C-8) and small arms system (as part of the series-produced machine guns NSVT-12.7)).

scholarly journals Prognostics-based adaptive control strategy for lifetime control of wind turbines

2021 ◽  
Author(s):  
Edwin Kipchirchir ◽  
Manh Hung Do ◽  
Jackson Githu Njiri ◽  
Dirk Söffker
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Control Strategy ◽  
Fatigue Loading ◽  
Operational Reliability ◽  
Operating Conditions ◽  
Rotor Blades ◽  
Time Step ◽  
Damage Level ◽  
Structural Loading

Abstract. Variability of wind profiles in both space and time is responsible for fatigue loading in wind turbine components. Advanced control methods for mitigating structural loading in these components have been proposed in previous works. These also incorporate other objectives like speed and power regulation for above-rated wind speed operation. In recent years, lifetime control and extension strategies have been proposed to guaranty power supply and operational reliability of wind turbines. These control strategies typically rely on a fatigue load evaluation criteria to determine the consumed lifetime of these components, subsequently varying the control set-point to guaranty a desired lifetime of the components. Most of these methods focus on controlling the lifetime of specific structural components of a wind turbine, typically the rotor blade or tower. Additionally, controllers are often designed to be valid about specific operating points, hence exhibit deteriorating performance in varying operating conditions. Therefore, they are not able to guaranty a desired lifetime in varying wind conditions. In this paper an adaptive lifetime control strategy is proposed for controlled ageing of rotor blades to guaranty a desired lifetime, while considering damage accumulation level in the tower. The method relies on an online structural health monitoring system to vary the lifetime controller gains based on a State of Health (SoH) measure by considering the desired lifetime at every time-step. For demonstration, a 1.5 MW National Renewable Energy Laboratory (NREL) reference wind turbine is used. The proposed adaptive lifetime controller regulates structural loading in the rotor blades to guaranty a predefined damage level at the desired lifetime without sacrificing on the speed regulation performance of the wind turbine. Additionally, significant reduction in the tower fatigue damage is observed.

High-loaded sub-6 nm Pt1Co1 intermetallic compounds with high-efficient performance expression in PEMFCs

2021 ◽  
Author(s):  
Qingqing Cheng ◽  
Shuai Yang ◽  
Cehuang Fu ◽  
Liang-Liang Zou ◽  
Zhi-Qing Zou ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Intermetallic Compounds ◽  
High Performance ◽  
Reduction Reaction ◽  
Operating Conditions ◽  
Practical Application ◽  
Efficient Performance ◽  
High Efficient ◽  
High Metal

High-loaded oxygen reduction reaction (ORR) Pt intermetallic compounds with high performance expression under PEMFC operating conditions are prerequisite for practical application. Nevertheless, high metal-loading would lead to the severe agglomeration...

A Method for Fatigue Evaluation of Trimaran Cross Structure With the Influence of Slamming

2017 ◽  
Author(s):  
Zhe Li ◽  
Huilong Ren ◽  
Kai Jin
Keyword(s):  
Stress Response ◽  
Fatigue Strength ◽  
Fatigue Damage ◽  
Linear Response ◽  
Operating Conditions ◽  
Wave Load ◽  
Hull Structure ◽  
Non Linear ◽  
Slamming Load ◽  
Cross Structure

Slamming is a highly non-linear phenomenon between hull structure and wave. Due to the special structure of trimaran, the slamming mode is extremely different from that of traditional vessel. Besides bow emergence and enter, the slamming phenomenon of the out shell at the cross structure is also obvious. In conventional hull structure fatigue strength evaluation, the slamming load is usually not considered. However, the slamming problem is unavoidable at danger load cases, and the stress concentration of the trimaran cross structure is serious. So it is dangerous to ignore the existence of slamming in serious load cases when evaluating the structural fatigue strength. Therefore, it is necessary to study the contribution of slamming load to fatigue damage. In this paper, a practical method for calculating and analyzing is presented to consider the effect of slamming on the fatigue strength of the trimaran cross structure to ensure that the fatigue life of the structure is closer to the true value. According to the linear theory, the relative motion and relative speed of the hull in wave and the stress response of the wave load on the structure are calculated firstly. Then, the stress response of the non-linear out shell slamming force is calculated. The linear response and non-linear response are combined. And the stress response time history under the combined action of slamming and wave load are obtained. Finally, the fatigue damage of the structure under dangerous operating conditions is calculated by the rain flow counting method. And the contribution value of the slamming load to the structural damage degree is calculated. The paper will put forward some reference suggestions for fatigue study calculation and evaluation of Trimaran cross structure with the influence of slamming.

scholarly journals Activated persulfate by iron-based materials used for refractory organics degradation: a review

2020 ◽  
Vol 81 (5) ◽  
pp. 853-875 ◽  
Author(s):  
Yanjiao Gao ◽  
Pascale Champagne ◽  
David Blair ◽  
Ouwen He ◽  
Tiehong Song
Keyword(s):  
Transition Metals ◽  
Advanced Oxidation Processes ◽  
Ferric Iron ◽  
Operating Conditions ◽  
Zero Valent Iron ◽  
Practical Application ◽  
Treatment Research ◽  
Iron Based ◽  
Materials Used ◽  
Refractory Organics

Abstract Recently, the advanced oxidation processes (AOPs) based on sulfate radicals (SRs) for organics degradation have become the focus of water treatment research as the oxidation ability of SRs are higher than that of hydroxyl radicals (HRs). Since the AOP-SRs can effectively mineralize organics into carbon dioxide and water under the optimized operating conditions, they are used in the degradation of refractory organics such as dyes, pesticides, pharmaceuticals, and industrial additives. SRs can be produced by activating persulfate (PS) with ultraviolet, heat, ultrasound, microwave, transition metals, and carbon. The activation of PS in iron-based transition metals is widely studied because iron is an environmentally friendly and inexpensive material. This article reviews the mechanism and application of several iron-based materials, including ferrous iron (Fe2+), ferric iron (Fe3+), zero-valent iron (Fe0), nano-sized zero-valent iron (nFe0), materials-supported nFe0, and iron-containing compounds for PS activation to degrade refractory organics. In addition, the current challenges and perspectives of the practical application of PS activated by iron-based systems in wastewater treatment are analyzed and prospected.

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