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1

Niezawodność podmiotów tworzenia i eksploatacji obiektów technicznych a niezawodność tych obiektów w świetle kategorii systemu wartości

Czajgucki Z.

Mechanik

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2011

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R. 84, nr 7(CD)

123-136

PL

W pracy przedstawiono punkt widzenia zagadnień niezawodności podmiotów tworzenia (badań, projektowania i wytwarzania) oraz eksploatacji obiektów technicznych, a także niezawodności tych obiektów, przez pryzmat etycznych, poznawczych i estetycznych kategorii. Scharakteryzowano relacje między wybranymi kategoriami a niezawodnością człowieka. Opisano zagadnienia: zawodność podmiotów (człowieka – osób) wyróżnionych procesów a niezawodność obiektów technicznych. Dokonano rozważań w tym zakresie.

EN

In this paper the author presents the point of view of reliability problems of subjects of creation (researches, designing and production) and exploitation of technical objects, and reliability of these objects, through ethical, cognitive and aesthetic categories. The relations between selected categories and reliability of human are characterized in the paper. Problems: unreliability of subjects ( human – individuals of distinguished processes and reliability of technical are being described. Considerations are made in this sphere. Their ending is constituted by a conclusion.

2

Methodology of maintainability and reliability prediction of technical objects

Kasprzyk Z.

Archives of Transport System Telematics

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2010

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Vol. 3, iss. 2

18-23

EN

In recent times, an avalanche increase in the importance of reliability in the engineering design can be seen. The main reason is a permanent competition on the market and a competition for the customer resulting in increasing continually the efficiency of technological processes. The need to achieve a high level of reliability and maintainability is particularly important, where a safe and rapid transportation of people and goods is of high importance. The above-presented state of affairs has inspired the author to present a paper on the methodology and tools to support the estimation of maintainability and reliability of technical objects, together with practical examples.

3

Wybrane zagadnienia niezawodności obiektów technicznych

Jachowicz T.

Przetwórstwo Tworzyw

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2009

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[R.] 15, nr 2

34-45

PL

W artykule przedstawiono podstawowe zagadnienia związane z niezawodnością obiektów technicznych. Scharakteryzowano definicje niezawodności oraz pojęć z nią związanych, takich jak trwałość, awaryjność czy nieuszkadzalność, ujęte w kategoriach ilościowych i jakościowych, a także wymieniono kryteria niezawodności. Przedstawiono miary niezawodności i funkcje niezawodności wraz z przykładami z różnych dziedzin techniki, a także sposoby zwiększania niezawodności. Scharakteryzowano podstawowe pojęcia opisujące niezawodność w ujęciu statystycznym oraz zagadnienia związane z prognozowaniem niezawodności obiektów technicznych.

EN

Basic problems related to a reliability of technical objects were presented in the article. The definitions of reliability and the ideas concerning the reliability like: durability, failure frequency, the lack of defects presented in the quantity and quality terms were described. Moreover the criteria of reliability were mentioned. The measure and the functions of reliability together with the examples coming from various fields of technique as well as the ways of increasing the reliability were presented. Basic problems describing the reliability from the statistical point of view as well as problems related to the prognosis of reliability of technical objects were presented.

4

Wielokryterialna optymalizacja niezawodnościowa oraz szacowanie stanu technicznego konstrukcji prętowych z zastosowaniem teorii zbiorów rozmytych

Niczyj J.

Prace Naukowe Politechniki Szczecińskiej. Katedra Teorii Konstrukcji

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2003

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Nr 581 (3)

3-229

EN

Optimum design as well as assessment of technical states of already civil existing structures are ones of the most important issues in engineering activities. Taking a decision on the effort state of the whole structure stands for a complicated problem, since it is difficult to proceed research related to an effort state or/and system damage. Information about the effort state of a structural member is often obtained on the basis of a visual evaluation or specialist's experiences. More frequently, in giving an opinion a verbal form is used. Such a linguistic qualification is defined as a qualitative valuation. In a decision problem, involved in expert computer codes for instance, linguistic information has to be expressed in terms of numerical data. Theory of fuzzy sets enables one to processing that linguistic information in order to make a decision that should be taken in complicated situations. Reliability-based multicriterion optimization is one of the more interesting engineering problems regarding structural designing and optimum decisions. This is because system properties and behaviour cannot be precisely observed, and statistical data related to uncertainties and imprecision data, related to, say, loading that the structure is subjected, are as a whole unavailable. A large number of optimum design problems define a set of constraints that are in conflict each other. On the other hand, the design constraints included in those problems are assumed as fuzzy (blurred) data. In many cases the values of required data can be given only in terms of their ranges, known as interval values. Also, their influences on taking a decision are expressed in the linguistic way only. Results followed from that interval analysis may be useful in qualitative assessments and taking decisions in order to improve utility states of the entire structure. It is shown in many examples of complex structures that the fuzzy sets may effectively be applied in a combination with the system reliability theory to estimate failure states. An original aspect of the work is thus the presentation of fuzzy failure probabilities with the help of fuzzy linguistic variables and interval analysis of fuzzy numbers. Operations on the intervals for each from the alpha-level of the fuzzy numbers are used. The alpha-level method allows one to calculate the probability of structural failure on various levels of uncertainties (fuzziness) of the system parameters. Descriptions of those uncertainties (inaccuracy) of the states of structural member damages in terms of the fuzzy sets enables one to estimate reliability of the existing structures in the case of insufficient system-parameter data. The alpha-levels method gives a parametric presentation of fuzzy design information and an evaluation of solutions on various levels in fuzzy analysis. An optimum solution depends on the value of the parameter alpha that denotes the achievement level through the allowable fuzzy quantities, as well as on the maximized value of the parameter lambda, which leads to general compromise solutions. In these solutions all the fuzzy objective functions and the fuzzy constraints are considered. Assessment of structural states is connected with the qualitative and quantitative evaluating. The fact that the last two evaluations are coupled is significant. An attempt to deal with the coupling aspect is introduced in Chapter 4 in the context of an original method, in which experimental research and expert evaluations of the structural effort states are combined to get various forms of a set of membership of function for appropriate visual evaluations. The expert evaluations are performed by questionnaire. To achieve agreement in those evaluations the method of fuzzy analysis of consensus in small groups is efficiently applied. As a result unique supports of linguistic values describing the technical state of structural members are given. These obtained evaluations are then assumed as a date-base in the next step of analysis. Effectiveness of the numerical algorithms worked-out is illustrated with the help of an optimum design problem of statically determinate and indeterminate trusses. Two conflict criteria defined for mass and displacement minima are defined in the objective functions. The system is subject to the stress and reliability constraints. It is assumed that the values of loading, admissible stresses and the probability of failure are described as fuzzy quantities. Chapter 9 shows reliability-based fuzzy multicriterion analysis of well-known aluminium 10-bar truss. An reliability scheme and same possible capacity forms of the truss are discussed. The probability of failure is computed basing upon a few dominant paths of failure that related to the margin of safety. The optimization techniques introduced in Chapters 8 and 9 stand for a new approach to optimum design analysis of truss systems. In this approach insufficient information taken into account can be leading to a more safe design point. All the solutions are obtained in these two chapters in the framework of the non-linear fuzzy programming. As shown by the author the calculations of the probability of failure and the determination of technical state of structure are based on visual assessments of the expert during the inspection process the problem formulated and solving algorithms presented in Chapters 10 are thus ones of the original aspects. A comparison of an technical state assessment of a structure through a long-time in intervals of repeated inspections is seemingly - by the author's knowledge - nonexisting in the literature. Moreover, it is particularity interesting when such a review is as most as specific the assessments were carried out for 7132 bars surfaces of the total length about 25000 m. More, the review is performed in the context of visual assessments, i.e. by linguistic values that are ones of the fuzzy variables. A comparison was made for the wooden roof of a hall in the 30-year interval, Chapter 11. The linguistic values followed from specific roofs trusses and obtained between two inspections, in 1964 and 1994, are compared via a number of histograms presented in this chapter. In author's opinion these histograms may stand for an inherent certification of the time state of either structural members or the entire structure whore at hand. These valuable data, when included in the recent data-base of structural states, and by periodical revives and comparisons (against previous states), enable the use in making proper decision.

5

Określanie i zastosowanie prawdopodobieństw występowania rozróżnialnych stanów wadliwego funkcjonowania obiektu

Szczepański P.

Biuletyn Wojskowej Akademii Technicznej

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2001

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Vol. 50, nr 8

25-40

PL

Przedstawiono sposób określania bezwarunkowych prawdopodobieństw występowania rozróżnialnych stanów wadliwego funkcjonowania złożonego obiektu technicznego. Algorytm postępowania uwzględnia funkcjonalną strukturę obiektu przy założeniu wzajemnej niezależności niezdatności jego elementów. Poniechano przyjęcia założenia o możliwości występowania w obiekcie co najwyżej jednego niezdatnego elementu. Wskazano na możliwość wykorzystania wyników pracy dla potrzeb diagnozowania obiektów bez tradycyjnego podziału tego diagnozowania na kontrolę zdatności i lokalizację uszkodzeń.

EN

It is presented the method for definition of unconditional probabilities of appearance of distinguishable states of errorous operation of complex technical object. The algorithm takes into account the functional structure of the object at assumption of the mutual independence of unserviceability of its elements. The possibility of appearance in the object at most a single unserviceable element was eliminated. It was pointed out the possibility of application the results of this work for the needs of the object diagnostics without traditional departing the diagnose on aptitude control and the damage localization.