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Wyszukujesz frazę "resonance analysis" wg kryterium: Temat


Wyświetlanie 1-22 z 22
Tytuł:
Untypical cases and incorrect results of vibration tests
Autorzy:
Wiśniewski, W.
Powiązania:
https://bibliotekanauki.pl/articles/242412.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
vibration tests
vibration analysis
resonance tests
resonance analysis
modal analysis
Opis:
The vibration analysis is the study of the behaviour and dynamic properties of mechanical structures under actuation by harmonic vibration forces. The aim of resonance tests of the structures is the experimental delimitation of frequencies and the modes of resonance vibrations. vibration analysis, or more precisely experimental vibration analysis, is the field of measuring and analyzing the dynamic response of mechanical structures when excited by a mechanical input. The broadly applied method of research relies on the harmonic actuation of vibrations and the measurement of respective parameters. Examples would include measuring the vibration of an aircraft load bearing structure when it is attached to an electromagnetic force actuator. Current vibration testing systems are composed of actuators set with their control and powering circuits, the vibration measurement transducers (typically accelerometers), an analog-to-digital converter to digitize analog instrumentation signals) and a system host computer to analyze the data and view it. The result of researcher own accumulated experiences and those experiences knownfrom the literature create the possibility for design o f a stochastic frame model describing, what type of resonances are possible to expect in the given or other type of structure. The cases submitted below became perceived and tested in the course of research of several aircraft, glider and helicopter designs in the Resonance Tests Program of the Institute of Aviation
Źródło:
Journal of KONES; 2009, 16, 1; 591-597
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research of the dynamic properties of structures the models of interpretation
Autorzy:
Wiśniowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/243504.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transport
aviation
vibration
structure testing
resonance analysis
modal analysis
Opis:
Experimental research of the dynamic properties of structures is performed during of prototype perfectioning, current exploitation and even after the withdrawal from the exploitation for the estimation of the residual durabilities. The aim for research of the dynamic properties of structures is the assurance of its safety, reliability, economic management and comfort. Researcher records the amplitudes of vibrations in the function of the actuation frequencies. Local raise of the amplitude is qualified as resonance. From the researcher point of view, the shape of resonance curves justifies the discrimination of two types of phenomena's: „single resonance" and „close frequencies resonance". For better understanding of these occurrences „the models of interpretation" were proposed. Up to three models of interpretation were assigned to the single resonance: one-degree-of-freedom system, one-degree-of-freedom system with share of the backlashes, two one-degree-of-freedom systems with the same frequencies. From above reasoning, the conclusion results that researcher can expect that the preliminary isolated single resonance belongs to one from the three, mentioned above cases. The judgment of these occurrences, just as the disentanglement of relations in the resonance pair with close frequencies, determines next challenge for the researcher.
Źródło:
Journal of KONES; 2008, 15, 3; 561-565
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of process parameters of friction stir welded AA5082-AA7075 butt joints using resonance fatigue properties
Autorzy:
Kumar, G.
Kumar, R.
Powiązania:
https://bibliotekanauki.pl/articles/200299.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
friction stir welding
dissimilar Al welding
resonance fatigue analysis
fracture surface analysis
ANOVA
Opis:
In this work, experiments were carried out to quantify the behaviour of friction stir welded (FSW) AA5082-AA7075 butt joints under tensile loading and completely reversed fatigue loading. Different samples were prepared to identify optimum tool rotational and travel speeds to produce FSW AA5082-AA7075 butt joints with the maximum fatigue life. ANOVA was performed, which confirmed that both tool speed nad tool rotation speed affect the tensile strength of the weld. The samples exhibit a considerable difference in their fatigue life and tensile strenght. This difference can be accounted to the presence of welding defects such as surface defects and porosity. S-N curve plotted for the sample shows a significantly high fatigue life at the lower stress ranges. Fracture surfaces were also analysed under scanning electron microscope (SEM). Study of the fracture surface of the sample that failed under fatigue loading showed that the surface was mainly divided in two zones. The first zone was the area of fatigue crack growth where each stress cycle, slowly and gradually, helped in the growth of crack. The second zone was the region of fast fracture where the crack growth resulted in the failure of the joint instantaneously. The fracture surface study of the sample that failed under tensile loading showed that the mode of failure was ductile in nature.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 1; 99-108
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Using the FRAM to Understand Arctic Ship Navigation: Assessing Work Processes During the Exxon Valdez Grounding
Autorzy:
Smith, D.
Veitch, B.
Khan, F.
Taylor, R.
Powiązania:
https://bibliotekanauki.pl/articles/117308.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
Arctic shipping
vessel grounding
grounding
Exxon Valdez
Arctic navigation
accident investigation
Functional Resonance Analysis Method (FRAM)
ship navigation
Opis:
Arctic shipping involves a complex combination of inter-related factors that need to be managed correctly for operations to succeed. In this paper, the Functional Resonance Analysis Method (FRAM) is used to assess the combination of human, technical, and organizational factors that constitute a shipping operation. A methodology is presented on how to apply the FRAM to a domain, with a focus on ship navigation. The method draws on ship navigators to inform the building of the model and to learn about practical variations that must be managed to effectively navigate a ship. The Exxon Valdez case is used to illustrate the model’s utility and provide some context to the information gathered by this investigation. The functional signature of the work processes of the Exxon Valdez on the night of the grounding is presented. This shows the functional dynamics of that particular ship navigation case, and serves to illustrate how the FRAM approach can provide another perspective on the safety of complex operations.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2018, 12, 3; 447-457
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FRAM modelling of the transfer of control over aircraft
Autorzy:
Rutkowska, P.
Krzyżanowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/196813.pdf
Data publikacji:
2018
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
functional resonance analysis method
FRAM
Safety-I
Safety-II
sociotechnical system
transfer of control
metoda analizy rezonansu funkcjonalnego
system socjotechniczny
Opis:
Aviation is the fastest growing but also the safest mode of transport. International aviation organizations give the highest priority to safety while creating aviation regulations. Therefore, a safety management system (SMS) has been created. Two approaches to assuring safety in aviation may be distinguished: Safety-I and Safety-II. Safety-I is the standard approach, focused on processing the information about malfunctioning features and system elements. On the other hand, Safety-II is a new approach to safety management, based on identifying the elements or functions of the system that work properly, which enables the system to confirm resilience to undesirable effects. One of the methods utilized for the Safety-II approach in order to study complex sociotechnical systems is the FRAM (functional resonance analysis method). The method is focused on analysing daily activities in various conditions in order to create a model of work performance. The models created based on the FRAM can be used for risk analysis, accident investigations and predicting possible future events affecting aviation safety. This method allows us to simulate system constraints and uncertain states. It can also be used as support for the air traffic safety management processes based on the Safety-II approach. The following article presents a developed FRAM model for the transfer of control over aircraft. This model constitutes an example of a coordination scheme limited to basic activities of air traffic control (ATC) services, providing a general framework for the construction and operation of the FRAM model.
Źródło:
Zeszyty Naukowe. Transport / Politechnika Śląska; 2018, 101; 159-166
0209-3324
2450-1549
Pojawia się w:
Zeszyty Naukowe. Transport / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Предупреждение осложнений имплантации на этапе первичной фиксации имплантата
Prevention of complications of implantation at primary implant fixation
Autorzy:
Vakulenko, V.I.
Goncharenko, E.V.
Schneider, S.A.
Kovshar, I.P.
Powiązania:
https://bibliotekanauki.pl/articles/1032533.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Kazimierza Wielkiego w Bydgoszczy
Tematy:
ортопантомография
конусно-лучевая компьютерная томография
частотнорезонансный анализ.
ортопантомографія
конусно-променева комп'ютерна томографія
частотнорезонансний аналіз.
orthopantomography
cone-beam computer tomography
resonance-frequency analysis
Opis:
Статья посвящена оптимизации планирования имплантации с целью снижения осложнений на этапе первичной фиксации имплантата. Сравнивались такие методики диагностики в имплантологии, как ортопантомография и конусно-лучевая компьютерная томография. Для определения механической стабильности имплантата использовался частотно-резонансный анализ.
The article is devoted to optimization of implant planning in order to reduce complications in primary fixation of the implant. Such diagnostic techniques in implantology as orthopantomography and cone-beam computed tomography were compared. The resonancefrequency analysis was used to determine the mechanical stability of the implant.
Стаття присвячена оптимізації планування імплантації з метою зниження ускладнень на етапі первинної фіксації імплантату. Порівнювалися такі методики діагностики в імплантології, як ортопантомографія і конусно-променева комп'ютерна томографія. Для визначення механічної стабільності імплантату використовувався частотно-резонансний аналіз.
Źródło:
Journal of Health Sciences; 2014, 4, 1; 263-274
1429-9623
Pojawia się w:
Journal of Health Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical investigations on vibrating motion with inertial load of vibratory pile hammer stiffly coupled with excavator
Autorzy:
Osiński, J.
Miedzińska, D.
Powiązania:
https://bibliotekanauki.pl/articles/247648.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
elastomer
vibrations
simulation
resonance
numerical analysis
Opis:
A vibratory pile hammer (VPH) is a mechanical device used to drive steel piles as well as tube piles into soil to provide foundation support for buildings or other structures. In order to increase the stability and the efficiency of the VPH work in the over-resonance frequency, a new VPH construction was developed in the Military University of Technology. The new VPH contains a system of counter-rotating eccentric weights, powered by hydraulic motors, and designed in such a way that horizontal vibrations cancel out, while vertical vibrations are transmitted into the pile. This system is suspended in the static parts by the adaptive variable stiffness pillows based on a smart material, magnetorheological elastomer (MRE), which rheological and mechanical properties can be reversibly and rapidly controlled by an external magnetic field. The work presented in the paper is a part of the modified VPH construction design process. It concerns the development of the numerical model of the VPH and soil interaction that will describe resonance conditions, resonance frequencies with consideration of soil susceptibility, coupling phenomenon and elastomer changeable stiffness. On the base of developed theoretical equations, the frequency of VPH piling will be regulated to assure the over-resonance work.
Źródło:
Journal of KONES; 2014, 21, 1; 189-195
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Modal Behaviour of Resonance Spruce Wood Samples (Picea abies L.)
Autorzy:
Mania, P.
Fabisiak, E.
Skrodzka, E.
Powiązania:
https://bibliotekanauki.pl/articles/177109.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
resonance wood
spruce wood
modal analysis
Opis:
Results of experimental modal analysis of a resonance and non-resonance spruce wood (Picea abies L.) are presented. The resonance wood came from a tree from Poland and Bosnia and Herzegovina, while the non-resonance wood came from the vicinity of Olsztyn from the north-eastern Poland. The modal parameters (modal frequency, modal damping and mode shapes) of the wood samples were determined for the samples of 8 mm in thickness. Modal analysis was made by pulse excitation. The resonance and non-resonance wood differ in the fundamental modal parameters as well as in the number of potential modes. Additionally, calculated values of damping factor are presented. The values are much bigger for a non-resonance wood than for good quality resonance spruce.
Źródło:
Archives of Acoustics; 2017, 42, 1; 23-28
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vibrations resonance estimation in marine structures
Autorzy:
Murawski, L.
Powiązania:
https://bibliotekanauki.pl/articles/247863.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
vibration
dynamic analysis
marine structures
propulsion system
crankshaft
resonance
Opis:
Dynamic analyses of marine structures are one of the most important during design process as well as during exploitation. Typically, two parts of vibrations calculations are performed. Firstly, natural vibrations frequencies and modes are determined. Forced vibrations analysis is the second step of calculations. Natural vibrations give us information about possibility (e.g. at which main engine speed) of dangerous vibrations amplitudes (resonances threat). Exact values of vibrations amplitudes are results of forced vibrations analysis. Confidence level (error value) of forced vibration calculations is much lower in comparison to uncertainty of natural vibration analysis. What is more, form engineering practice point of view, natural vibrations frequencies estimation (resonance avoidance) is the most important during dynamic analysis of marine structures with propulsion systems. In the paper some examples of dynamic characteristics estimation and their changing methods (possibility) was presented. Utility of relatively simple models, with low degree of freedom number, was discussed. Modelling methods depending on the analysis target of marine slow-speed crankshafts was presented. Advantages and disadvantages of subcritical and supercritical design of marine propulsion system were discussed. An example of propulsion system natural torsional vibrations simplified analysis was presented. Location of the main torsional resonance is one of the most important decisions during design process of the marine propulsion system. Methods of fast and easy estimation as well as changing possibility of natural vibrations frequencies of marine structures is the main objective of presented paper.
Źródło:
Journal of KONES; 2014, 21, 1; 175-182
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and analytical research on resonance phenomena of vibrating head with MRE regulating element
Autorzy:
Miedzińska, D.
Gieleta, R.
Osiński, J.
Powiązania:
https://bibliotekanauki.pl/articles/265035.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
vibratory pile hammer
resonance
vibrations
Fourier analysis
analiza Fouriera
wibracje
rezonans
Opis:
A vibratory pile hammer (VPH) is a mechanical device used to drive steel piles as well as tube piles into soil to provide foundation support for buildings or other structures. In order to increase the stability and the efficiency of the VPH work in the over-resonance frequency, a new VPH construction was developed at the Military University of Technology. The new VPH contains a system of counter-rotating eccentric weights, powered by hydraulic motors, and designed in such a way that horizontal vibrations cancel out, while vertical vibrations are transmitted into the pile. This system is suspended in the static parts by the adaptive variable stiffness pillows based on a smart material, magnetorheological elastomer (MRE), whose rheological and mechanical properties can be reversibly and rapidly controlled by an external magnetic field. The work presented in the paper is a part of the modified VPH construction design process. It concerns the experimental research on the vibrations during the piling process and the analytical analyses of the gained signal. The results will be applied in the VPH control system.
Źródło:
International Journal of Applied Mechanics and Engineering; 2015, 20, 1; 201-208
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The assessment of the technical condition of SO-3 engine turbine blades using an impulse test
Autorzy:
Milewicz, Julia
Mokrzan, Daniel
Szymański, Grzegorz M.
Powiązania:
https://bibliotekanauki.pl/articles/2097507.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Naukowe Silników Spalinowych
Tematy:
jet engine
turbine
modal analysis
resonance
silnik odrzutowy
turbina
analiza modalna
rezonans
Opis:
The paper presents the effects of the application of an experimental impulse test as a method of diagnosis of the technical condition of an SO-3 engine turbine blade fitted in a TS-11 Iskra aircraft. The aim of the test was to investigate the frequency characteristics of the blades and discuss differences between the frequency spectrum of the investigated component before and after its damage. The acoustic response measurements were performed to the signal generated by an impact hammer on the fully functional and intentionally damaged blades. The recorded signals were converted from the domain of time to the domain of frequency using the Fast Fourier Transform (FFT). The results of the FFT were the Frequency Response Functions (FRF) of the sound of the blades, based on which the statistical analysis of the resonance frequencies was carried out. The influence of the mechanical damage of the blade on the shape and characteristics of the frequency spectrum was confirmed, which substantiated the effectiveness of the impulse test in the diagnostic assessment of jet engine components.
Źródło:
Combustion Engines; 2021, 60, 1; 24--29
2300-9896
2658-1442
Pojawia się w:
Combustion Engines
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An integrated study for solving high vibration problem of a deep well turbine pump
Autorzy:
El-Gazzar, Dalia M.
Powiązania:
https://bibliotekanauki.pl/articles/2203638.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
vibration analysis
finite element analysis
modal analysis
resonance
vertical turbine pump
analiza drgań
analiza elementów skończonych
analiza modalna
rezonans
Opis:
Mechanical vibrations are a common problem encountered in many machines, especially for vertical turbine pumps. These pumps are generally difficult to stiffen or damp, but the effective diagnosis must begin with an understanding of the underlying vibratory sources. In the present work, a deep well vertical turbine pump experienced extremely high vibrations for a long time although it still being new. It hasn't been in operation for over 6 months. The pump system suffers from extremely high vibration levels relative to the rotational speed (1X motor dominant frequency). An efficient strategy was implemented by using well-conceived techniques. The experimental modal analysis confirmed a presence of a natural frequency. Modifications were carried out to overcome resonance. Finite element analysis was done to determine the reed critical frequencies as a powerful tool to identify and mitigate vibration issues. On-site motor balancing was done to remove vibrations due to the residual imbalance. Results revealed decreasing vibration level by about 66% after solving all problems.
Źródło:
Diagnostyka; 2023, 24, 2; art. no. 2023209
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Clamped Bar Model for the Sompoton Vibrator
Autorzy:
Wong, T. H.
Dayou, J.
Ngu, M. C. D.
Hang, J. H. W.
Liew, W. Z. H.
Powiązania:
https://bibliotekanauki.pl/articles/176855.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
vibrator
clamped bar
single degree of freedom system
exact analysis
resonance frequency
Opis:
The sompoton is one of famous traditional musical instruments in Sabah. This instrument consists of several parts with the vibrator being the most important one. In this paper, the vibrator is modeled as a clamped bar with a uniformly distributed mass. By means of this model, the fundamental frequency is analyzed with the use of an equivalent single degree of freedom system (SDOF) and exact analysis. The vibrator is made of aluminum in different sizes and is excited using a constant air jet to obtain its fundamental resonance frequency. The fundamental frequency obtained from the experimental measurement is compared with the theoretical values calculated based on the equivalent SDOF and exact analysis theories. It is found that the exact analysis gives a closer value to the experimental results as compared to the SDOF system. Although both the experimental and theoretical results exhibit the same trend, they are different in magnitude. To overcome the differences in both theories, a correction factor is added to account for the production errors.
Źródło:
Archives of Acoustics; 2013, 38, 3; 425-432
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of the parameters of multi-mass direct drive system
Autorzy:
Łuczak, D.
Powiązania:
https://bibliotekanauki.pl/articles/1811899.pdf
Data publikacji:
2012
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
identification of the mechanical
resonance frequencies
spectral analysis
Fourier transform
chirp signal
sine signal
Opis:
This paper presents methods for the identification of mechanical resonance of multi mass direct drive system. Methods have been applied in the field of digital signal processing. Was used spectral analysis to identify the mechanical resonance frequencies of direct drive with elastic connection. Discussed methods of identification have been verified by simulation and real system. Two different input signal was presented: sine and chirp wave. Both input signals gave good result for determine mechanical resonance frequencies, however sine wave with variable frequency determined only for the number of frequency corresponding to the input signal frequency gave better result for determine mechanical antyresonance frequencies.
Źródło:
Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej. Studia i Materiały; 2012, 66, 32; 62-66
1733-0718
Pojawia się w:
Prace Naukowe Instytutu Maszyn, Napędów i Pomiarów Elektrycznych Politechniki Wrocławskiej. Studia i Materiały
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zagrożenia rezonansowe maszyn podstawowych górnictwa odkrywkowego
Resonance risk to machines working in mining of lignite coal
Autorzy:
Pietrusiak, D.
Powiązania:
https://bibliotekanauki.pl/articles/348283.pdf
Data publikacji:
2011
Wydawca:
Akademia Wojsk Lądowych imienia generała Tadeusza Kościuszki
Tematy:
maszyny górnictwa odkrywkowego
analiza modalna
drgania
zagrożenia rezonansowe
opencast mining machines
modal analysis
vibrations
resonance risk
Opis:
Do kategorii maszyn podstawowych górnictwa odkrywkowego zalicza się wielonaczyniowe koparki kołowe oraz zwałowarki. Ich budowa oraz charakter pracy powodują, że są one silnie narażone na obciążenia dynamiczne. W artykule przedstawiono możliwości wystąpienia zagrożenia zjawiskiem rezonansu, w zależności od obiektu i jego warunków pracy. Wskazano możliwe sposoby badania charakterystyk dynamicznych metodami eksperymentalnymi oraz numerycznymi.
Bucket wheel excavators and stackers are basic machines working in open pit mines. Those machines are highly exposed to dynamic load due to operational conditions and their construction. The article presents the possibility and conditions of resonance occurrence. Furthermore, the author discusses possible methods of modal models identification with the use of numerical and experimental methods.
Źródło:
Zeszyty Naukowe / Wyższa Szkoła Oficerska Wojsk Lądowych im. gen. T. Kościuszki; 2011, 4; 238-245
1731-8157
Pojawia się w:
Zeszyty Naukowe / Wyższa Szkoła Oficerska Wojsk Lądowych im. gen. T. Kościuszki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of the frequency response of the ERC 1400 Bucket Wheel Excavator boom, during the excavation process
Autorzy:
Popescu, Florin Dumitru
Radu, Sorin Mihai
Andraș, Andrei
Kertesz (Brînaș), Ildiko
Powiązania:
https://bibliotekanauki.pl/articles/2064395.pdf
Data publikacji:
2019
Wydawca:
STE GROUP
Tematy:
bucket wheel excavator
damping
frequency response
modal analysis
resonance
wielonaczyniowa koparka kołowa
tłumienie
pasmo przenoszenia
analiza modalna
rezonans
Opis:
The paper deals with the modal analysis and frequency response analysis of a bucket wheel excavator (BWE) boom, obtained by simulation, based on a virtual model of an existing BWE boom. The boom, which generally is realized as a spatial truss, is the most vulnerable subsystem of the BWE, being submitted to severe operational loads characterized by very pronounced cyclical, dynamic and stochastic variability. This vulnerability is the consequence of its shape and constructive parameters and the nature, source and character of the external exciting loads to which it is exposed. The classical approach recommended by standards and norms cannot predict the occurrence of failures caused by vibration, which produces fatigue due to the load’s cyclical variability and the deformation produced by resonant vibration of some constitutive elements. As exciting load we considered the operational forces acting on the bucket wheel. In this manner we can take into account the constructive features - with modal analysis, and the vibration regime - with frequency response analysis. The proposed method is useful both in the design phase of new load-bearing structures of truss type subjected to high-variability forces, and also in refurbishment or improvement phases of the existing structures of this kind.
Źródło:
New Trends in Production Engineering; 2019, 2, 1; 153--167
2545-2843
Pojawia się w:
New Trends in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametric Sensitivity Analysis of Factors Affecting Sound Transmission Loss of Multi-Layered Building Elements Using Taguchi Method
Autorzy:
Garg, N.
Kumar, A.
Maji, S.
Powiązania:
https://bibliotekanauki.pl/articles/178151.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
spectrum adaptation terms
weighted sound reduction index
orthogonal array
OA
analysis of variance
ANOVA
mass-air-mass resonance
Opis:
The paper presents application of Taguchi method in optimizing the sound transmission loss through sandwich gypsum constructions and those comprising of masonry concrete blocks and gypsum boards in order to investigate the relative influence of the various parameters affecting the sound transmission loss. The application of Taguchi method for optimizing sound transmission loss has been rarely reported. The present work uses the results analytically predicted on “Insul” software for various sandwich material configurations as desired by each experimental run in an L8 orthogonal array. The relative importance of the parameters on single-number rating, Rw (C, Ctr) is evaluated in terms of percentage contribu- tion using Analysis of Variance (ANOVA). The ANOVA method reveals that type of studs, steel stud frame and number of gypsum layers attached are the key factors controlling the sound transmission loss characteristics of sandwich multi-layered constructions.
Źródło:
Archives of Acoustics; 2014, 39, 2; 165-176
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Harmonic analysis of the wind-loaded bar dome at the Satellite Services Centre in Psary
Analiza harmoniczna kopuły prętowej Centrum Usług Satelitarnych w Psarach obciążonej wiatrem
Autorzy:
Szaniec, W.
Zielińska, K.
Powiązania:
https://bibliotekanauki.pl/articles/231008.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
obciążenie wiatrem
analiza harmoniczna
rezonans
drgania własne
drgania wymuszone
wind load
harmonic analysis
resonance
natural vibrations
forced vibrations
Opis:
The research paper presents the results of the dynamic analysis of an existing bar dome subjected to wind loads. The calculation model of the structure was constructed using the finite element method. The dome was subjected to the standard wind pressure, assuming that it is operates in a harmonic manner. The numerical analyses were performed with the application of Autodesk Robot and MES3D. The analysis focused on the impact of selected factors such as the frequency of forcing, wind gustiness coefficient and structural damping on the behaviour of structures.
Kopuły prętowe to obiekty inżynierskie charakteryzujące się dużymi rozmiarami przy stosunkowo niewielkich przekrojach elementów i jednocześnie dużej lekkości całej konstrukcji. Ustroje te, ze wzglądu na swoją małą sztywność, są wrażliwe na działanie czynników atmosferycznych, w szczególności wiatru. Obciążenie to charakteryzuje się dużą zmiennością, jest w znacznym stopniu czynnikiem losowym, co w sposób istotny utrudnia wykonywanie obliczeń. W przypadku projektowania takich obiektów, na podstawie geometrii obiektu, położenia i charakterystyki terenu przyjmuje się obciążenie w postaci parcia wiatru i na tej podstawie wykonuje obliczenia statyczne. W przypadku rozpatrywanych konstrukcji takie podejście nie zawsze wydaje się uzasadnione, niekiedy wskazane jest wykonywanie analiz dynamicznych. Nawet przy niewielkich siłach wymuszających, czasem trudno zauważalnych, istnieje niebezpieczeństwo wystąpienia zjawiska rezonansu, zarówno całej konstrukcji, jak i jej poszczególnych elementów. Obciążenie wiatrem może być przedstawione jako iloczyn statycznego parcia wiatru oraz funkcji zmieniającej tę wartość w czasie. W pracy przyjęto ją w postaci harmonicznej. Ze względu na brak rzeczywistych charakterystyk wiatrowych przyjęto dość szeroki zakres parametrów opisujących to obciążenie (częstość wymuszenia, współczynniki porywistości, prędkość bazowa).
Źródło:
Archives of Civil Engineering; 2016, 62, 1; 37-50
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vibration analysis of a bucket wheel excavator boom using rayleigh’s damping model
Autorzy:
Popescu, Florin Dumitru
Radu, Sorin Mihai
Kotwica, Krzysztof
Andraș, Andrei
Kertesz (Brînaș), Ildiko
Dinescu, Stela
Powiązania:
https://bibliotekanauki.pl/articles/2064357.pdf
Data publikacji:
2019
Wydawca:
STE GROUP
Tematy:
bucket wheel excavator
damping
frequency response
modal analysis
resonance
wielonaczyniowa koparka kołowa
tłumienie
pasmo przenoszenia
analiza modalna
rezonans
Opis:
For the ERc 1400-30/7 type bucket wheel excavator (BWE) used in various Romanian open pit mines, a virtual model of the boom was constructed in SolidWorks. On this model, the variable in time forces acting during the excavation process were simulated, and the time history analysis (time response) was performed. This dynamic time response analysis was performed for excavation of homogenous material only, considering the damping as being of Rayleigh’s type, where the damping matrix is a linear combination of the mass and stiffness matrices. Based on the conducted analysis, the displacements of the boom during excavation were observed.
Źródło:
New Trends in Production Engineering; 2019, 2, 1; 233--241
2545-2843
Pojawia się w:
New Trends in Production Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metody określania struktury polisacharydów
Methods for determining polysaccharides structure
Autorzy:
Samaszko-Fiertek, J.
Kuźma, M.
Dmochowska, B.
Ślusarz, R.
Madaj, J.
Powiązania:
https://bibliotekanauki.pl/articles/172410.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
polisacharydy
monosacharydy
degradacja oksydacyjna
analiza metylacyjna
acetoliza
NMR
magnetyczny rezonans jądrowy
MS
polysaccharides
monosaccharides
oxidative degradation
methylation analysis
acetolysis
nuclear magnetic resonance (NMR)
Opis:
Sequencing of polysaccharides is difficult to achieve because of the heterogeneous nature of the polysaccharide structure, high molecular weight (the size of a polysaccharide varies between approximately 16,000 and 16,000,000 daltons (Da)), and polydispersity of the polymer chains. The following information is essential to determine the primary structure of a polysaccharide: • monosaccharide composition: nature and molar ratios of the monosaccharide building blocks; • relative configuration of monosaccharides: d or l; • anomeric configuration: α- or β-configuration of the glycosidic linkage; • ring size: presence and distinction of furanosidic and pyranosidic rings; • linkage patterns: linkage positions between the monosugars and branches; • sequences of monosaccharide residues in the repeating units; • substitutions: position and nature of OH–modifications, such as O–phosphorylation, acetylation, O-sulfation, etc.; • molecular weight and molecular weight distribution. A polysaccharide extracted from plant materials or food products is usually purified before being subjected to structural analysis. The first step of characterizing a polysaccharide is the determination of its purity, which is reflected by its chemical composition, including total sugar content, level of uronic acids, proteins, ash, and moisture of the preparation. The second step is the determination of monosaccharide composition, which will unveil structural information such as the number of monosaccharides present in the polysaccharide and how many of each sugar unit. NMR spectroscopy has become the most powerful and noninvasive physicochemical technique for determining polysaccharide structures. It can provide detailed structural information of carbohydrates, including identification of monosaccharide composition, elucidation of α- or β-anomeric configurations, establishment of linkage patterns, and sequences of the sugar units in oligosaccharides and/or polysaccharides. Monosaccharide composition can be determined also by analysis of totally acid hydrolyzed polysacharide using high performance liquid chromatography (HPLC) or gas chromatography (GC). The ring size and glycosidic linkage positions of sugar units in a polysaccharide could be established by methylation analysis and/or cleavage reduction. The anomeric configuration is conventionally determined by oxidation, and this method can be combined with mass spectrometry to obtain more structural information.
Źródło:
Wiadomości Chemiczne; 2016, 70, 5-6; 299-318
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metody trójwymiarowej analizy ruchu człowieka
The methods of three dimensional human motion analysis
Autorzy:
Sacha, E.
Powiązania:
https://bibliotekanauki.pl/articles/99214.pdf
Data publikacji:
2008
Wydawca:
Politechnika Śląska. Katedra Biomechatroniki
Tematy:
biomechanika
analiza chodu
pomiar ruchu
system IDEEA
system Aurora
system Moven
system CMS-HS
rezonans magnetyczny
3D
biomechanics
gait analysis
motion capture
IDEEA system
Aurora system
Moven system
CMS-HS system
magnetic resonance
Opis:
W artykule przedstawione zostały główne techniki pomiarowe, stosowane w trójwymiarowej analizie ruchu człowieka, jako alternatywa dla systemów optoelektronicznych. Artykuł ma charakter poglądowy, przedstawia ogólną charakterystykę i zasadę działania metod badawczych.
This paper is a general demonstration of the newest, non-optical method, used in 3D motion analysis. It contains a few main measuring techniques, like electromagnetic tracking system, accelerometer system, ultrasound method and the other, which are the alternatives for video-based optical method of human motion analysis. There is also a notice about using the Magnetic Resonance Imaging for kinematic analysis in the future.
Źródło:
Aktualne Problemy Biomechaniki; 2008, 2; 141-146
1898-763X
Pojawia się w:
Aktualne Problemy Biomechaniki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ procedury termostatowania oraz sposobu przeprowadzenia pomiaru na wyniki oceny zawartości fazy stałej w wybranych tłuszczach
Autorzy:
Pawlowicz, R
Powiązania:
https://bibliotekanauki.pl/articles/828448.pdf
Data publikacji:
2004
Wydawca:
Polskie Towarzystwo Technologów Żywności
Tematy:
tluszcz mlekowy
olej palmowy
loj wolowy
maslo kakaowe
tluszcze
faza stala
oznaczanie
metody analizy
rezonans magnetyczny jadrowy
milk fat
palm oil
beef suet
cocoa butter
fat
solid state
determination
analysis method
nuclear magnetic resonance
Opis:
Pulsacyjny magnetyczny rezonans jądrowy jest metodą zalecaną przez normy międzynarodowe do oznaczania zawartości fazy stałej w tłuszczach. Przed wykonaniem tego oznaczenia tłuszcze poddaje się termostatowaniu. Procedury termostatowania uwzględniają różnice w sposobie krystalizacji tłuszczów. Czynnik ten był podstawą podziału tłuszczów na grupy. Zgodnie z normą ISO 8292, dotyczącą oznaczania zawartości fazy stałej, tłuszcze podzielono na cztery grupy: (1) masło kakaowe i jego równoważniki, (2) olej palmowy, (3) łój i jego frakcje oraz (4) inne tłuszcze. W innych normach (IUPAC, AOCS, PORIM) tłuszcze podzielono na dwie grupy: (1) masło kakaowe i jego równoważniki oraz (2) inne tłuszcze. W przypadku oleju palmowego oraz łoju istnieją zatem dwie różne procedury termostatowania. Norma ISO zaleca wielogodzinne termostatowanie tych tłuszczów, natomiast pozostałe normy tylko jednogodzinne chłodzenie w temp. 0°C. W niniejszej pracy oznaczono zawartość fazy stałej w tłuszczach należących, zgodnie z normą ISO, do czterech różnych grup, tj. w tłuszczu kakaowym, oleju palmowym, łoju wołowym oraz tłuszczu mlecznym. W każdym z badanych tłuszczów zawartość fazy stałej oznaczono po zastosowaniu jednogodzinnego chłodzenia oraz po wielogodzinnym termostatowaniu. Tłuszcz kakaowy, olej palmowy oraz łój termostatowano zgodnie z normą ISO. Do tłuszczu mlecznego zastosowano metodę jak do tłuszczu kakaowego. Wielogodzinne termostatowanie tłuszczu ma na celu przeprowadzenie go w trwałą formę krystaliczną. W przypadku tłuszczów, w których taka przemiana zachodzi, tzn. tłuszczu kakaowego, oleju palmowego oraz łoju, temperowanie powoduje wzrost zawartości fazy stałej. W tłuszczach niewymagających temperowania, np. w tłuszczu mlecznym, etap ten powoduje obniżenie zawartości fazy stałej poniżej temperatury, w której tłuszcz był stabilizowany. Zgodnie z normą ISO, oznaczając zawartość fazy stałej, wykonuje się pomiar równoległy. Niektóre normy (IUPAC, PORIM) przewidują również możliwość wykonania pomiarów szeregowych. Gdy zastosowana procedura nie jest odpowiednia dla danego tłuszczu, tzn. nie umożliwia przeprowadzenia tłuszczu w trwałą formę krystaliczną, wówczas stosując pomiar szeregowy otrzymuje się wyższe wyniki zawartości fazy stałej. Spowodowane to jest zachodzeniem przemian polimorficznych w trakcie termostatowania badanego tłuszczu w kolejnej, coraz wyższej temperaturze. W przypadku zastosowania prawidłowej procedury pomiar równoległy i szeregowy daje takie same wyniki.
Pulsed NMR is a method recommended by international standards for determination of solid fat content (SFC). Fats are thermostated before SFC are determined. Fats are divided into several groups owing to differences in their crystallization processes. Different thermostating procedures have been worked out for each group. According to the ISO 8292 standard on the determination of SFC, fats are divided into four groups: (1) cocoa butter and its equivalents, (2) palm oil, (3) tallow and its fractions, and (4) other fats. According to other standards (IUPAC, AOCS, PORIM), fats are divided into two groups: (1) cocoa butter and its equivalents, and (2) other fats. Therefore, two different procedures are used to thermostate palm oil and tallow. The ISO 8292 standard recommends that these fats are tempered for many hours, whereas other standards recommend only 1 hr cooling at 0°C. In this study, SFC in fats that, according to ISO 8292, belong to four different groups (cocoa butter, palm oil, tallow, and milk fat) were determined. Solid fat contents in samples were determined after a 1 hr cooling and many hr lasting tempering processes. With regard to cocoa butter, palm oil and tallow, ISO procedures specifically designed for these fats were used. Milk fat was tempered in a similar way as cocoa butter. Fats are tempered in order to change them into a stable crystalline form. In case of fats in which such changes occur, i.e. cocoa butter, palm oil and tallow, tempering causes an increase in SFC. In fats not requiring tempering, e.g., milk fat, this step causes a decrease in SFC at a temperature appearing lower as the temperature at which the fat was tempered. Additionally, some standards (IUPAC, PORIM) include a possibility of taking serial measurements. When procedure applied is not suitable for a given fat, i.e. when it is not possible to change the fat into a stable crystalline form, then, a higher SFC is obtained while taking series measurements. This effect is caused by polymorphic transformations occurring during the process of thermostating samples at successively increasing temperatures. If a procedure applied is fitting, both the parallel and serial measurements supply the same results.
Źródło:
Żywność Nauka Technologia Jakość; 2004, 11, 2; 69-80
1425-6959
Pojawia się w:
Żywność Nauka Technologia Jakość
Dostawca treści:
Biblioteka Nauki
Artykuł
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