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Tytuł:
Dynamic analysis of torsional discrete-continuous systems with position-dependent variable inertia
Autorzy:
Pielorz, A.
Powiązania:
https://bibliotekanauki.pl/articles/279507.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
variable inertia
discrete-continuous systems
wave approach
Opis:
In the paper, dynamic investigations of multi-mass discrete-continuous systems torsionally deformed are performed taking into account the position-dependent mass moment of inertia of one of rigid bodies. It is assumed that the rigid body representing a motor moves with a variable velocity. An originally nonlinear problem is linearized, and the wave approach leading to solving equations with a retarded argument having variable coefficients is used for the solution. Exemplary numerical calculations are done for a three-mass system.
Źródło:
Journal of Theoretical and Applied Mechanics; 2014, 52, 1; 107-115
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A mode-III crack with variable surface effects
Autorzy:
Wang, X.
Schiavone, P.
Powiązania:
https://bibliotekanauki.pl/articles/282009.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
surface elasticity
variable surface moduli
mode-III crack
Cauchy singular integro-differential equation
Opis:
We study the contribution of variable surface effects to the antiplane deformation of a linearly elastic material with a mode-III crack. The surface elasticity is incorporated using a modified version of the continuum based surface/interface model of Gurtin and Murdoch. In our discussion, the surface moduli are not constant but vary along the crack surfaces. Using Green’s function method, the problem is reduced to a single first-order Cauchy singular integro-differential equation, which is solved numerically using Chebyshev polynomials and a collocation method. Our results indicate that the gradient of the surface shear modulus exerts a significant influence on the crack opening displacement and on the singular stress field at the crack tips.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 4; 1319-1327
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on vibration evolution of a ball bearing without the cage under local variable-diameter raceway damage
Autorzy:
Zhou, Enwen
Zhao, Yanling
Zhang, Huanqing
Powiązania:
https://bibliotekanauki.pl/articles/2200877.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
ball bearing
vibration evolution
variable-diameter raceway
damage
Opis:
This article presents an analysis of vibration evolution of a ball bearing without the cage. A vibration model in which time-varying displacement, time-varying stiffness, contact force and collision force are comprehensively considered, is proposed. On this basis, the law of motion of the bearing is studied. It is shown that a variable-diameter raceway affects the radius of curvature, which effects the dispersion of rolling elements. The damaged variable -diameter raceway leads to discrete failure, contact force and collision force of rolling elements, which are main reasons that cause vibration mutation. The bearing motion changes from quasi-periodic to chaotic motion.
Źródło:
Journal of Theoretical and Applied Mechanics; 2023, 61, 1; 129--146
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermoelastic stresses in functionally graded rotating annular disks with variable thickness
Autorzy:
Allam, M. N. M.
Tantawy, R.
Zenkour, A. M.
Powiązania:
https://bibliotekanauki.pl/articles/949321.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
functionally graded
variable thickness
semi-analytical approach
rotating
thermal effect
Opis:
This article presents semi-analytical solutions for stress distributions in exponentially and functionally graded rotating annular disks with arbitrary thickness variations. The disk is under pressure on its boundary surfaces and exposed to temperature distribution varying linearly across thickness. Material properties are supposed to be graded in the radial direction of the disk and obeying to two different forms of distribution of volume fraction of constituents. Different conditions at boundaries for stresses and displacement are discussed. Accurate and efficient solutions for displacement and stresses in rotating annular disks are determined using infinitesimal theory. Numerical results are carried out and discussed for different cases. It can be deduced that the gradient of material properties and thickness variation as well as the change of temperature sources have a specific effect in modern applications.
Źródło:
Journal of Theoretical and Applied Mechanics; 2018, 56, 4; 1029-1041
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Asymptotic analysis of nonlinearly elastic shells with variable thickness
Asymptotyczna analiza nieliniowo sprężystych powłok o zmiennej grubości
Autorzy:
Gratie, L.
Powiązania:
https://bibliotekanauki.pl/articles/280441.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
asymptotic analysis
nonlinearly elastic shells
Koiter's model
variable thickness
energy functional
variational problems
Opis:
P.G.Ciarlet recently proposed, and justified with A.Roquefort through the method of formal asymptotic expansions, a nonlinear shell model for shells with constsnt thickness. This model is analogous in its form to the model formerly proposed by W.T.Koiter, but is more amenable to numerical computations. In the same spitit, we propose and we justify here, again by the method of formal asymptotic expansion, a more general nonlinear model, which is valid for shells with variable thickness.
W pracy odniesiono się do nieliniowego modelu powłoki o stałej grubości, który uprzednio został zweryfikowany za pomocą metody formalnych rozwinięć asymptotycznych. Jego konstrukcja ma właściwości analogiczne do innych modeli spotykanych w literaturze, ale jest bardziej dogodna przy zastosowaniu symulacji numerycznej. W tym samym duchu zaprezentowano w pracy metodę formalnych rozwinięć asymptotycznych do zbudowania bardziej ogólnego modelu o podobnym charakterze, ale dotyczącego powłoki o zmiennej grubości.
Źródło:
Journal of Theoretical and Applied Mechanics; 2003, 41, 3; 487-508
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of cross-ply laminates with piezoelectric fiber-reinforced composite actuators using four-variable refined plate theory
Autorzy:
Rouzegar, J.
Abad, F.
Powiązania:
https://bibliotekanauki.pl/articles/949140.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
cross-ply laminates
electromechanical loading
four-variable theory
PFRC actuator
Opis:
This study presents an analytical solution for cross-ply composite laminates integrated with a piezoelectric fiber-reinforced composite (PFRC) actuator subjected to electromechanical loading using the four-variable refined plate theory. This theory predicts parabolic variation of transverse shear stresses and satisfies the zero traction on the plate surfaces without using the shear correction factor. Using the principle of minimum potential energy, the governing equations for simply supported rectangular plates are extracted and the Navier method is adopted for solution of the equations. The comparison of obtained results with other common plate theories and the exact solution indicates that besides the simplicity of the presented formulation, it is very accurate in analysis of laminated composite plates integrated with PFRC. Also the effects of the thickness ratio, aspect ratio, number of layers, staking sequence and amount of electrostatic loading on the displacements and stresses are investigated and the obtained findings are reported.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 2; 439-452
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fatigue life of aluminium alloy 6082 t6 under constant and variable amplitude bending with torsion
Autorzy:
Karolczuk, A.
Kurek, M.
Łagoda, T.
Powiązania:
https://bibliotekanauki.pl/articles/281975.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
variable amplitude loading
multiaxial fatigue
aluminium alloy
critical plane approach
Opis:
The paper presents the comparison of experimental and calculated fatigue lives for EN AW-6082 T6 aluminium alloy. Hour-glass shaped specimens have been subjected to constant and variable amplitude uniaxial and multiaxial loadings, i.e. plane bending, torsion and their proportional combinations with zero mean values. Three multiaxial fatigue criteria based on the critical plane approach have been verified being the linear combination of shear and normal stresses on the critical plane. For the variable-amplitude loading, the rainflow cycle counting method and Palmgren-Miner hypothesis have been applied. The best fatigue criteria are pointed in the final conclusions.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 2; 421-430
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free vibration analysis of thick disks with variable thickness containing orthotropic-nonhomogeneous material using finite element method
Autorzy:
Zafarmand, H.
Kadkhodayan, M.
Powiązania:
https://bibliotekanauki.pl/articles/279473.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
free vibration
carbon nanotube
functionally graded material
thick disk
variable thickness
graded finite element method
Opis:
Free vibration analysis of thick functionally graded nanocomposite annular and solid disks with variable thickness reinforced by single-walled carbon nanotubes (SWCNTs) is presented. Four types of distribution of uniaxial aligned SWCNTs are considered: uniform and three kinds of functionally graded (FG) distribution through radial direction of the disk. The effective material properties of the nanocomposite disk are estimated by a micro mechanical model. The axisymmetric conditions are assumed and employing the graded finite element method (GFEM), the equations are solved. The solution is considered for four different thickness profiles, namely constant, linear, concave and convex. The achieved results show that the type of distribution and volume fraction of CNTs and thickness profile have a great effect on normalized natural frequencies.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 4; 1005-1018
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and validation of a single-jack variable Mach number nozzle in a cryogenic transonic wind tunnel
Autorzy:
Yu, Chengguo
Zhang, Zhili
Wang, Ning
Nie, Xutao
Peng, Qiang
Chen, Zhenhua
Powiązania:
https://bibliotekanauki.pl/articles/2200829.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
cryogenic
flow uniformity
single-jack nozzle
transonic wind tunnel
variable
Mach number
Opis:
The wind tunnel with variable Mach numbers controlled by a single jack is highly desired in the aerospace, automobile and building industry due to its superior controllability and working range. Decreasing the temperature of a test gas is an efficient and economical approach to achieving higher Reynolds numbers that accommodate all working statuses of test subjects, which however, brings new challenges to the wind tunnel design nowadays. This paper proposes a new design concept of a single-jack variable Mach number nozzle based on its particular cryogenic characteristics, as the nozzle is the core structure to achieve variable Mach numbers. The contours of the nozzle under different Reynolds numbers and Mach numbers are modeled and solved by an incomplete elliptic integral, followed by modification with cryogenic characteristics. A 0.3-m cryogenic wind tunnel is utilized as a validation platform for the nozzle design, resulting in designed contours being in line with the measured contours. Moreover, the root means square (RMS) deviations of Mach number 1.3 at the core position are controlled within 0.011 in low and high temperatures, which surpasses the other existing wind tunnels.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 4; 719--732
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of variable orthotropy upon the stability of thin-walled rectangular plates
Autorzy:
Kubiak, T.
Powiązania:
https://bibliotekanauki.pl/articles/279601.pdf
Data publikacji:
1999
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
stability
thin-walled structures
orthotropy
Opis:
The author analyse the stability loss in thin-walled orthotropic plates, their principal directions of orthotropy being pararell to the wall edges, for plates with the orthotropy ratio, B=Ex/Ey varying widthwise. The analysis was carried out within the elastic range. Numerical tests were made on thin plates with the loaded edgessimply supported; unloaded edges were tested for different kinds of support (clamped, simply supported, free-edge). Plates were subject to loads causing uniform and linearly varying displacement of edges. The problem was solved using Koiter's first-order asymptotic theory of conservative systems stability (Koiter, 1963). Results of numerical calculations were presented as graphs describing the relationship between a critical value (force of moment) and the perameter defining defining orthotropy across the plate width.
W pracy analizowano utratę stateczności cienkościennych płyt ortotropowych o głównych kierunkach ortotropii równoległych do krawędzi ścian. Badano płyty charakteryzujące się zmiennym wzdłuż szerokości współczynnikiem ortotropii B=Ex/Ey. Analiza prowadzona była w zakresie sprężystym. Badano płyty cienkie podparte na obciążonych brzegach przegubowo, a na nie obciążonych brano pod uwagę różne rodzaje podparcia (utwierdzenie, podparcie przegubowe, swobodny brzeg). Płyty poddano obciążeniom powodującym równomierne i liniowo zmienne zbliżenie brzegów. Zagadnienie rozwiązano przy zastosowaniu pierwszego rzędu asymptotycznej teorii stateczności układów zachowawczych Koitera. Wyniki obliczeń numerycznych przedstawiono w postaci wykresów opisujących zależność wielkości krytycznej (siły lub momentu) od parametru określającego zmienność ortotropii wzdłuż szerokości płyty.
Źródło:
Journal of Theoretical and Applied Mechanics; 1999, 1; 129-145
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An internal-state-variable based viscoelastic-plastic model for polymers
Autorzy:
Suchocki, C.
Powiązania:
https://bibliotekanauki.pl/articles/279925.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
polymers
rheology
constitutive equation
finite element method
Opis:
In this study, a new viscoelastic-plastic constitutive model which has been formulated by utilizing the formalism of stress-like internal state variables is introduced. The developed constitutive equation allows for a good description of the inelastic material response of polymeric materials over a wide range of strain rates. An algorithm for numerical integration of the model equations has been derived. The FE implementation of the constitutive equation is widely discussed and the results of solving several exemplary problems are presented.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 3; 593-604
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of selected dynamic features of a two-wheeled transmission system
Autorzy:
Krawiec, P.
Powiązania:
https://bibliotekanauki.pl/articles/281204.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
transmission
variable gear ratio
mathematical model
Opis:
The paper presents results of analysis of selected dynamic features of an uneven-running two- -wheeled strand transmission. The characteristic features of such type of transmissions is the ability of obtaining variable kinematic and dynamic features by the application of wheels with a noncircular envelope. Particularly, high interest of application of uneven-running transmissions was done in the previous century. At that time, a concept of application of such transmissions for process and machine control was invented. The applications in textile and engineering industry are widely known. A mathematical model of the multiplying transmission is presented. Few versions of dynamic features of the transmission for different loads and solid moments of inertia are examined. The presented results can be very helpful for designers of classical and uneven-running strand transmissions.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 2; 461-467
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A continuum description of failure waves
Autorzy:
Said, H.
Glimm, J.
Powiązania:
https://bibliotekanauki.pl/articles/279743.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
brittle fracture
failure wave
internal variable
dissipative systems
variational principle
Opis:
Shattering of a brittle material such as glass occurs dynamically through a propagating failure wave, which however, can not be assigned to any of the classical wave. In this paper, we build a thermodynamically consistent theory based on the idea that a failure wave is analogous to a deflagration wave. Our theory admits, as special cases, the classical models of Feng and Clifton. Two fundamental thermodynamic functions form the basis of our theory. This approach allows for the construction of a new variational principle and a Lagrangian formulation. Finally, the theory is linearized to interpret specific experimental observations.
Źródło:
Journal of Theoretical and Applied Mechanics; 2018, 56, 3; 657-674
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Green’s function in frequency analysis of circular thin plates of variable thickness
Autorzy:
Żur, K. K.
Powiązania:
https://bibliotekanauki.pl/articles/280832.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
circular plates
Green's functions
Neumann series
Opis:
Free vibration analysis of homogeneous and isotropic circular thin plates with variable distribution of parameters by using Green’s functions (solution to homogeneous ordinary differential equations with variable coefficients) is considered. The formula of Green’s function (called the influence function) depends on the Poisson ratio and the coefficient of distribution of plate flexural rigidity, and the thickness is obtained in a closed-form. The limited independent solutions to differential Euler equations are expanded in the Neumann power series using the Volterra integral equations of the second kind. This approach allows one to obtain the analytical frequency equations as the power series rapidly convergens to exact eigenvalues for different values of the power index and different values of the Poisson ratio. The six lower natural dimensionless frequencies of axisymmetric vibration of circular plates of constant and variable thickness are calculated for different boundary conditions. The obtained results are compared with selected results presented in the literature.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 4; 873-884
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A kinematic internal variable approach to dynamics of beams with a periodic-like structure
Autorzy:
Mazur-Śniady, K.
Powiązania:
https://bibliotekanauki.pl/articles/280643.pdf
Data publikacji:
2001
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
dynamics
beam
periodic-like structure
homogenization
Opis:
In the paper a new averaged model for the dynamic response of a periodic-like straight beam with a variable cross-section is proposed. The beam under consideration is assumed to interact with Winkler's subsoil having periodic-like properties. Assumptions of the Bernoulli-Euler beam theory as well as the influence of axial forces on deflection of the beam are taken into account. The approach adapted in the paper is based on concepts of the tolerance averaging approach by Woźniak (1999). In this way it is possible to formulate the averaged equations of the structured beams, which describe the length-scale effect.
Zastosowanie modelu kinematycznych wewnętrznych zmiennych w dynamice belek o prawie periodycznej strukturze. Celem pracy jest zaproponowanie nowego uśrednionego modelu dynamicznej odpowiedzi prawie periodycznej prostej belki o zmiennym przekroju. Rozważana belka współpracuje z podłożem winklerowskim o prawie okresowo zmiennych właściwościach. Zagadnienie rozpatruje się w ramach teorii Bernoulliego-Eulera, z uwzględnieniem wpływu sił osiowych na ugięcie belki. Zastosowanie metody uśredniania tolerancyjnego, Woźniak (1999), umożliwia sformułowanie uśrednionych równań belki o prawie periodycznej strukturze, które opisują efekt skali.
Źródło:
Journal of Theoretical and Applied Mechanics; 2001, 39, 1; 175-194
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł

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