Temat: lifetime - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Methodology of threat autonomous assessment and forecasting the lifetime of the marine structure
Autorzy:: Murawski, L.
Powiązania:: https://bibliotekanauki.pl/articles/245864.pdf
Data publikacji:: 2015
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: monitoring systems
non-destructive tests
ship structures lifetime prediction
damage identification
damage localization
lifetime forecasting
Opis:: Structural Health Monitoring (SHM) is a natural extension and supplement of Non-Distractive Tests (NDT). Structure assessment during periodical NDT tests is performed by highly trained human team. However, during long sea voyage, ship crew has no knowledge and possibility for detailed assessment and, what is more, has no knowledge lifetime predicting of ship structure. SHM systems should have good designed sensors types, distribution, and automatic recording unit. However, most important (and most difficult for designing) is autonomous and self-contained procedures for marine structures hazard assessment. In the paper, basic assumptions for numerical algorithms of signal processing, damage identification and localization, threat assessment and forecasting of structure lifetime are presented. SHM systems can be based on several different measurements techniques like: comparative vacuum monitoring, electromagnetic layer, Lamb waves, vibration based methods, acoustic emission, and fibre optics. Last three methods are most promising in the marine environment, according to the author experience. Global ship hull deformation should be monitored as quasi-continuous measurements. Optical Time-Domain Reflectometer method (OTDR) is planned by author for hull global deformation monitoring. Some local strain-stress concentration of hull structure and propulsion system bearings' reactions will be monitored by Fibre Bragg Grating (FBG) sensors. Both techniques (OTDR and FBG) have been shortly described in the paper.
Źródło:: Journal of KONES; 2015, 22, 2; 163-168
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Analysis of mileage to engine oil removing in the natural exploitation of passenger cars
Analiza przebiegów do wymiany oleju silnikowego w eksploatacji naturalnej samochodów
Autorzy:: Sitnik, L. J.
Powiązania:: https://bibliotekanauki.pl/articles/245595.pdf
Data publikacji:: 2009
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: eksploatacja
silnik pojazdu
olej silnikowy
czasokres
exploitation
car engine
engine oil
lifetime
analysis
Opis:: Leading to reformation of proecologic abilities of transport's vehicles and especially cars vehicles are connected with properly economy of the working liquids. It intakes should be optimal. This postulate is working in an activity of cars' tycoons and producers of working liquids. In this case a good example is lifetime of engines' oils. By one hand it leads to lengthen of engine's oil lifetime by improvement of its abilities, by second hand producers are limiting time of oil's change but admittedly that mileage is constantly rising. Everything it leads to constantly drop of the oil's unit consumption. There are exist extra possibilities of improving an oil consumption if oil's unit consumption treats like proecologic parameter. The base of that are changes in oil lifetime based on exploitations' terms for particular copy of vehicle. By one hand it secures of properly use car vehicle by second hand it resists the human factor in exploitation process, thanks that it excludes situations where oil will be changed to early - as a consequence of extra consumption or to late - as a probability of engines' damages. From the analysis of solid constant mileage to change engine's oil comes how big problem is it. Properly researches and conclusions presented in this publication.
Dążenie do poprawy proekologicznych właściwości środków transportu, w tym samochodów osobowych, związane jest, między innymi, z prawidłową gospodarką płynami roboczymi. Ich zużycie powinno być optymalizowane. Postulat ten jest urzeczywistniany w działalności zarówno wytwórców pojazdów jak też producentów płynów eksploatacyjnych. Dobrym przykładem jest tu kwestia zużycia olejów silnikowych. Z jednej strony dąży się do tego by oleje mogły pracować jak najdłużej - ciągle doskonaląc ich właściwości, z drugiej producenci ograniczają przebiegi do ich wymiany, ale przyznać trzeba, że przebiegi te ulegają ciągłemu wzrostowi. Wszystko to prowadzi do nieustannego „jednostkowego" obniżania zużycia oleju silnikowego. Jeśli traktować jednostkowe zużycie oleju silnikowego jako parametr o znaczeniu proekologicznym to trzeba stwierdzić, że istnieją dalsze możliwości jego poprawy. Podstawową jest wprowadzenie elastycznych przebiegów do wymian oleju, wynikających z warunków eksploatacji konkretnego egzemplarza pojazdu. Z jednej strony zabezpiecza to właściwe użytkowanie pojazdu, z drugiej natomiast, powoduje znaczne ograniczenie ingerencji „ czynnika ludzkiego " w proces eksploatacji, a zatem pozwala wykluczyć sytuacje gdzie olej silnikowy wymieniany jest przedwcześnie - co skutkuje nieuzasadnionym jego zużyciem, lub zbyt późno - co wzmaga prawdopodobieństwo uszkodzeń silnika. O tym jak ważny jest to problem można przekonać się analizują dane dotyczące „sztywnych" przebiegów do wymiany oleju silnikowego. Odpowiednie badania i wynikające stąd wnioski, przedstawiono w niniejszej publikacji.
Źródło:: Journal of KONES; 2009, 16, 3; 367-373
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Outline of the method for prediction of lifetime achieved by ayionic hydraulic drives operated under real field conditions
Autorzy:: Ułanowicz, L.
Powiązania:: https://bibliotekanauki.pl/articles/242145.pdf
Data publikacji:: 2009
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: lifetime
probability density function
hydraulic drive
pump delivery
structural parameter
deterioration rate
wear and tear
Opis:: The presented approach to predict lifetime of avionic hydraulic drives belongs to a priori (accelerated) methods as by its nature it does not reeuire to continue tests until a hydraulic subassembly or drive reaches its boundary value of a structural parameter. The method uses distributions of a random variable with time-dependent variance as models for lifetime prediction. Variations of structural parameters over a discretional period of time are described with use of the Gaussian distribution with the assumption that the course of the process when the structural parameters are subject to deterioration comprises the entire probabilistic characteristic that defines resistance of the hydraulic drive to a wear and tear process. In that context distributions of characteristics for variations of structural parameters were determined for a selected period of time and it served as a basis to find out parameters for the distribution of the defect-free operation time. The completed functional and design decomposition of an example avionic hydraulic drive made it possible to obtain a hierarchical description of the hydraulic drive, to identify its structural parameters that are available during the drive operation as well as to define a set of measurable out put parameters of a system, a module (a hydraulic system) and a block (a hydraulic subassembly). The set of measurable output parameters attributable to the hydraulic system in question is described with use of mathematic equations that result from fundamental equations for hydraulic systems dynamics, i.e. the mass conservation law, the principle of momentum and angular momentum conservation as well as the energy conservation law.
Źródło:: Journal of KONES; 2009, 16, 2; 473-484
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Examination of hydraulic amplifiers in the aspect of lifetime prediction
Autorzy:: Jastrzębski, G.
Ułanowicz, L.
Powiązania:: https://bibliotekanauki.pl/articles/244003.pdf
Data publikacji:: 2010
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: hydraulic amplifier
distributing slider
hydrodynamic radial force
insensitivity (dead) zone of a hydraulic amplifier
durability (lifetime)
Opis:: The paper presents the lifetime analysis for a hydraulic amplifier and considers two types of the flow distributing devices, i.e. a linear distributings lider and a rotarys lider. Description of essential properties associated with operation of distributing devices in hydraulic amplifiers is included with particular attention to analysis of processes that affect wear and tear of hydraulic amplifiers and influence quality of their operation. In that context a set of parameters that determine operation quality of hydraulic amplifiers was found out where mutual independence of the parameters, their unambiguousness and measurability served as the criteria for selection there of two methods of analysis were used that took account for the foregoing assumption, i.e. the method of maximum informative capacity of the parameter and the method that assumes maximum alteration of the technical condition due to execution of the test. The completed examinations made it possible to find out characteristic curves for hydraulic amplifiers with a linear distributing slider as well as with a rotary slider with regard to their accumulated operation time. Further predictions of the hydraulic amplifier lifetime take advantage of the assumption that the deterioration effect of functional parameters attributable to hydraulic amplifiers is represented by a series of time-related values (y1,y2.....yn)i.e. a set of discrete observations {y1=ksi(teta)} associated with an unsteady stochastic process ksi(teta). The relationships how functional parameters o f a hydraulic amplifier vary in pace with its operation time t are described by means of the Gaussian distribution with the assumption that the course of a functional parameter deterioration corresponds to its aggregated characteristic curve that represents resistance of a distributing device embedded into a hydraulic amplifier to wear and tear processes. Wear of crucial parts within a hydraulic amplifier is measured in terms how functional parameters of that part associated with its accuracy, sensitivity and switching speed are getting worse and worse as time goes by.
Źródło:: Journal of KONES; 2010, 17, 3; 165-172
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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