PL
 |
EN
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 11

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  mode
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available Analysis of the Influencing Factors of the Acoustic Performance of the Muffler Considering Acoustic-structural Coupling
Zhao Bo, Li He
Archives of Acoustics
|
2022
|
Vol. 47, No. 4
479--490
EN
In the calculation of the acoustic performance of mufflers, the walls of mufflers are usually treated rigidly without considering the acoustic-structural coupling, but the results so calculated differ significantly from the actual situation. Based on the basic equations, the article derives the finite element equations of the muffler system while considering the acoustic-structural coupling effect and theoretically analyses the connection between the acoustic-structural coupling system and the structural and acoustic modes. The structural and acoustic modes of the muffler are calculated and the reasons for the mutation of the transmission loss curve of the muffler when the acoustic-structural coupling is considered are analysed. The results show that the acoustic-structural coupling is the result of the interaction between the structure and the air inside the expansion chamber under acoustic excitation, which manifests mutations in the sound pressure inside the muffler in some frequency bands. Then, using a single-chamber muffler as an example, the transmission loss is used to characterise the performance of the muffler. The effects of different factors such as shell thickness, structure, porous media material lining, and restraint method on the acoustic-structural coupling effect of the muffler are analysed, and the structure of a double-chamber muffler is successfully optimised according to the conclusions.
2
Content available Dynamic modeling and parametric analysis of differential gearbox used in electric vehicle
Ullah Najeeb, Song Chaosheng, Zhu Caichao, Ou Zhuxiang, Tan Cong
Journal of Theoretical and Applied Mechanics
|
2020
|
Vol. 58 nr 1
73--85
EN
The aim of this study is to perform the modeling and parametric analysis of dynamic mesh force in the light of resonance modes. Firstly, dynamic modeling of a differential gearbox has been performed by using the lumped parameter method. Then, the resonant points from Campbell diagrams were studied for the first three critical harmonic orders. Furthermore, two case studies were proposed in order to investigate the impact of radial clearance and face width on the dynamic mesh force along with resonance. Simultaneously, resonance identification and elimination were studied for two working conditions. Results show that the influence of lowering face width of pinions is more effective on mesh force reduction and resonance elimination as opposed to the first case study by enhancing wheel side mesh stiffness.
3
Content available remote Construction schedule of works as combinatorial optimization problem
Dytczak M., Ginda G.
Czasopismo Techniczne. Budownictwo
|
2014
|
R. 111, z. 2-B
283--289
EN
Construction schedule optimization generally deals with the identification of the feasible sequence of activities and allocation of modes that provide the most efficient construction performance according to the assumed evaluation criteria. The specific technological order of activities results in the numerous feasible sequences of activities and availability of alternative modes results in the numerous mode combinations. Construction scheduling becomes, therefore, a difficult combinatorial problem that is usually underestimated by the planners. This is the main reason for obtaining schedules that result in construction implementation lasting too long and costing too much. It is, nevertheless, possible to identify the construction schedules that provide excellent results. A simple, simulationbased approach is presented in this paper. Its originality results from nature of applied model and a way the calculations are made. The effectiveness of the approach is illustrated by means of a sample analysis based on data provided by [1]. The approach also proved useful for solving scheduling problems in engineering practice.
PL
Optymalizacja harmonogramu przedsięwzięcia polega na doborze takiej dopuszczalnej kolejności wykonywania prac oraz przydzieleniu takich sposobów wykonania operacjom, które zapewnią najlepsze możliwe, zgodnie z przyjętymi kryteriami oceny harmonogramu, wykonanie przedsięwzięcia. Z technologicznego porządku prac wynika zwykle duża, a często nawet astronomiczna liczba ich dopuszczalnych uporządkowań. Złożoność procesu harmonogramowania dodatkowo podwyższa dostępność alternatywnych sposobów wykonania prac. Harmonogramowanie przedsięwzięć stanowi więc w istocie trudne, a przy tym niedoceniane przez planistów, zagadnienie kombinatoryczne. W rezultacie otrzymujemy harmonogramy odpowiadające nadmiernie czaso- i kosztochłonnej realizacji przedsięwzięcia. Przy odrobinie wysiłku można jednak uzyskać harmonogramy, które odpowiadają krótkiej i taniej realizacji przedsięwzięcia. Temu celowi służy również autorskie narzędzie symulacyjne przedstawione w pracy. Stanowi ono oryginalne podejście zarówno w zakresie modelu, jak i sposobu wykonywania obliczeń, do których dane zaczerpnięto z pracy [1]. Wyniki pracy zostały także zastosowane w praktyce inżynierskiej.
4
Content available Quantifiable measures of the structural degradation of construction materials
Kaźmierczak H., Pawłowski T., Wojniłowicz Ł.
Diagnostyka
|
2013
|
Vol. 14, No. 4
77--83
EN
The authors have outlined a method for analysing the fatigue degradation of mechanical structures described in terms of variations in the mobility of dynamic impedances, their real and imaginary parts and fluctuations in the strength of dynamic rigidity and the strength of the internal damping of structures expressed as a function of degradation time (the number of degrading impulse impacts). The variations are identified over the full scope of destruction ranging from nucleation to dominant fracturing. Such an identification is carried out by the method of experimental modal analysis and by energy-based methods with the use of a mechatronic accelerated testing station. The paper provides definitions of the related measurable measures of the process[6]. The point is illustrated with an overview of selected strength characteristics of modern construction steel.
PL
Przedstawiono zarys metody analizy procesu degradacji zmęczeniowej struktur mechanicznych, opisanej przez charakterystyki zmian mobilności dynamicznych, impedancji, ich części rzeczywistych i części urojonych oraz zmian mocy sił sztywności dynamicznych i mocy sił tłumienia wewnętrznego struktur w funkcji czasu procesu degradacji(liczba degradujących uderzeń impulsowych). Charakterystyki te wyznacza się w pełnym zakresie procesu niszczenia od nukleacji do dominującego pęknięcia metodą eksperymentalnej analizy modalnej i metodami energetycznymi z zastosowaniem mechatronicznego stanowiska badań przyspieszonych. Praca zawiera definicje mierzalnych miar procesu. Jako przykład zamieszczono wybrane charakterystyki właściwości wytrzymałościowych nowoczesnych stali konstrukcyjnych.
5
Content available Do primary event uncertainty distributions impact top event distribution?
Górska M.
Zeszyty Naukowe Wydziału Elektroniki i Informatyki Politechniki Koszalińskiej
|
2011
|
Nr 3
133--145
EN
The risk analysis is an essential element of planning, production and operation of technical equipment. This paper deals with the fault tree. The fault tree analysis belongs to the most commonly used risk assessment methods. The main aim of the paper is to ask for the question: does the top event uncertainty assessment have a relationship with adopted assumption of primary events distribution?To achieve this aim a computer simulation that involve random numbers, commonly known as the Monte Carlo method, was used. The research makes use of the Beta, Lognormal, Johnson SJ and truncated Normal distribution.
6
Content available remote Transitive modes
Nazari E., Movsisyan Y. M.
Demonstratio Mathematica
|
2011
|
Vol. 44, nr 3
511-522
EN
In this paper the connection between the right (left) invertible medial algebras and the right (left) group of binary operations is studied. As a consequence, we prove the structure results for transitive modes.
7
Content available remote Representation of modals
Pilitowska A., Zamojska-Dzienio A.
Demonstratio Mathematica
|
2011
|
Vol. 44, nr 3
535-556
EN
The main aim of this paper is to describe the free objects in arbitrary varieties of modals (semilattice ordered idempotent and entropic algebras)and give some new representations of modals.
8
Content available remote Axial dispersion models and their basic properties
Bartova D., Jakes B., Kukal J.
Archives of Control Sciences
|
2009
|
Vol. 19, no. 1
5-22
EN
The paper is oriented to summary of important basic relations, which characterize behavior of four axial dispersion models (AEO: axial enforced closed-open model, ACO: axial closed-open model, ACC: axial closed-closed model, AOO: axial open-open model) and three referential models (ideal mixed model, plug flow model, cascade of ideal mixers without back-mixing). Selected basic properties (parametric characteristics) of these models can be used for parameter identification of included hydrodynamic flow structure models. Mathematical description of models including initial and boundary conditions, transfer function, model transient response to Dirac impulse as weighting (impulse) function, model transient response to step function as step response are included in this study. There are also included further characteristics of impulse function: raw moments up to 4th order, variance, variation coefficient, skewness , kurtosis, location and value of mode. Complete set of these characteristics for all studied models is collected (model-by-model) in seven tables. The authors declare several properties of weighting function as key ones: value of 1st raw (dimensional) moment, parametric values and mode properties, related to dependence on Peclet number. The plots of parametric values and mode properties vs. Peclet number are mentioned in the paper for four studied axial dispersion models.
9
Content available remote On the Normalized Cut
Nadarajah S.
Fundamenta Informaticae
|
2008
|
Vol. 86, nr 1-2
169-173
EN
In the recent paper by Soundararajan and Sarkar (2003), the normalized cut, a graph partitioning measure for perceptual organization, was shown to be a sum of two beta distributed random variables and expressions derived for its mean and mode. Here, it is pointed out that the given expression for the mode is incorrect. The correct expression is derived and the implications of the error discussed.
10
Content available remote Abstract Barycentric Algebras
Romanowska A.B., Smith J.D.H., Orłowska E.
Fundamenta Informaticae
|
2007
|
Vol. 81, nr 1-3
257-273
EN
This paper presents a new approach to the study of (real) barycentric algebras, in particular convex subsets of real affine spaces. Barycentric algebras are cast in the setting of two-sorted algebras. The real unit interval indexing the set of basic operations of a barycentric algebra is replaced by an LP-algebra, the algebra of ukasiewicz Product Logic. This allows one to define barycentric algebras abstractly, independently of the choice of the unit real interval. It reveals an unexpected connection between barycentric algebras and (fuzzy) logic. The new class of abstract barycentric algebras incorporates barycentric algebras over any linearly ordered field, the B-sets of G. M. Bergman, and E. G. Manes' if-then-else algebras over Boolean algebras.
11
Content available remote Adaptive kernel estimation of the mode in a nonparametric random design regression model
Ziegler K.
Probability and Mathematical Statistics
|
2004
|
Vol. 24, Fasc. 2
213--235
EN
In a nonparametric regression model with random design, where the regression function m is given by m (x) = E(Y |X = x), estimation of the location θ (mode) and size m (θ) of a unique maximum of m is considered. As estimators, location θ and size m (θ) of a maximum of the Nadaraya-Watson kernel estimator m for the curve m are chosen. Within this setting, we establish joint asymptotic normality and asymptotic independence for θ and m (θ) (which can be exploited for constructing simultaneous confidence intervals for θ and m (θ)) under mild local smoothness assumptions on m and the design density g (imposed in a neighborhood of θ). The bandwidths employed for m are data-dependent and of plug-in type. This is handled by viewing the estimators as stochastic processes indexed by a so-called scaling parameter and proving functional central limit theorems for those processes. In the same way, we obtain, as a by-product, an asymptotic normality result for the Nadaraya-Watson estymator itself at a finite number of distinct points, which improves on previous results.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.