The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Tomasz Kapitaniak - One of the best experts on this subject based on the ideXlab platform.
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Zener Internal Damping in modelling of axially moving viscoelastic beam with time-dependent tension
International Journal of Non-Linear Mechanics, 2007Co-Authors: K. Marynowski, Tomasz KapitaniakAbstract:Abstract Non-linear vibrations of axially moving beam with time-dependent tension are investigated in this paper. The beam material is modelled as three-parameter Zener element. The Galerkin method and the fourth order Runge–Kutta method are used to solve the governing non-linear partial-differential equation. The effects of the transport speed, the tension perturbation amplitude and the Internal Damping on the dynamic behaviour of the system are numerically investigated. The Poincare maps and bifurcation diagrams are constructed to classify the vibrations. For small values of the transport speed and the amplitude of periodic perturbation the system is asymptotically stable with its response tending to zero. With the increase of parameters one can observe the coexistence of attractors. Regular and chaotic motion occur when the Internal Damping increases.
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kelvin voigt versus burgers Internal Damping in modeling of axially moving viscoelastic web
International Journal of Non-linear Mechanics, 2002Co-Authors: Krzystof Marynowski, Tomasz KapitaniakAbstract:Stability and oscillation characteristics of two-dimensional axially moving web have been investigated. The application of one-dimensional beam-like models of the web allows the identi1cation of instability regions and the estimation of the critical speed. For the beam material two di3erent models, i.e., Kelvin–Voigt and B # have been considered. The numerical solutions of full non-linear and linearized equations have been compared. The e3ects of axially travelling speed and the Internal Damping on dynamical stability of axially moving web have been studied in details. Our numerical studies of Kelvin– Voigt and Burger’s models show that both models give similar results for small values of Internal Damping and can be used to describe the dynamics of axially moving webs made from materials with Internal Damping coe7cient smaller than 3 × 10 −5 . For the materials with larger Damping coe7cient the B # urgers model gives more reliable results. ? 2002 Elsevier
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Kelvin–Voigt versus Bürgers Internal Damping in modeling of axially moving viscoelastic web
International Journal of Non-Linear Mechanics, 2002Co-Authors: Krzystof Marynowski, Tomasz KapitaniakAbstract:Stability and oscillation characteristics of two-dimensional axially moving web have been investigated. The application of one-dimensional beam-like models of the web allows the identi1cation of instability regions and the estimation of the critical speed. For the beam material two di3erent models, i.e., Kelvin–Voigt and B # have been considered. The numerical solutions of full non-linear and linearized equations have been compared. The e3ects of axially travelling speed and the Internal Damping on dynamical stability of axially moving web have been studied in details. Our numerical studies of Kelvin– Voigt and Burger’s models show that both models give similar results for small values of Internal Damping and can be used to describe the dynamics of axially moving webs made from materials with Internal Damping coe7cient smaller than 3 × 10 −5 . For the materials with larger Damping coe7cient the B # urgers model gives more reliable results. ? 2002 Elsevier
Krzystof Marynowski - One of the best experts on this subject based on the ideXlab platform.
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kelvin voigt versus burgers Internal Damping in modeling of axially moving viscoelastic web
International Journal of Non-linear Mechanics, 2002Co-Authors: Krzystof Marynowski, Tomasz KapitaniakAbstract:Stability and oscillation characteristics of two-dimensional axially moving web have been investigated. The application of one-dimensional beam-like models of the web allows the identi1cation of instability regions and the estimation of the critical speed. For the beam material two di3erent models, i.e., Kelvin–Voigt and B # have been considered. The numerical solutions of full non-linear and linearized equations have been compared. The e3ects of axially travelling speed and the Internal Damping on dynamical stability of axially moving web have been studied in details. Our numerical studies of Kelvin– Voigt and Burger’s models show that both models give similar results for small values of Internal Damping and can be used to describe the dynamics of axially moving webs made from materials with Internal Damping coe7cient smaller than 3 × 10 −5 . For the materials with larger Damping coe7cient the B # urgers model gives more reliable results. ? 2002 Elsevier
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Kelvin–Voigt versus Bürgers Internal Damping in modeling of axially moving viscoelastic web
International Journal of Non-Linear Mechanics, 2002Co-Authors: Krzystof Marynowski, Tomasz KapitaniakAbstract:Stability and oscillation characteristics of two-dimensional axially moving web have been investigated. The application of one-dimensional beam-like models of the web allows the identi1cation of instability regions and the estimation of the critical speed. For the beam material two di3erent models, i.e., Kelvin–Voigt and B # have been considered. The numerical solutions of full non-linear and linearized equations have been compared. The e3ects of axially travelling speed and the Internal Damping on dynamical stability of axially moving web have been studied in details. Our numerical studies of Kelvin– Voigt and Burger’s models show that both models give similar results for small values of Internal Damping and can be used to describe the dynamics of axially moving webs made from materials with Internal Damping coe7cient smaller than 3 × 10 −5 . For the materials with larger Damping coe7cient the B # urgers model gives more reliable results. ? 2002 Elsevier
Milan Uhríčik - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Amplitude Dependence of Internal Damping of AZ31 and AZ61 Alloys in Initial State and after Deformation
Manufacturing Technology, 2019Co-Authors: Milan Uhríčik, Peter Palček, Mária Chalupová, Zuzana Dresslerová, Patrícia HanusováAbstract:The article is focused on the analysis of amplitude dependence on the Internal Damping of magnesium alloys in initial state and after deformation. Resonance method, based on continuous excitation of oscillations of the specimen, was used in experimental measurements, with the entire apparatus vibrating at a frequency close to the resonance. The Damping capacity, characterized by dissipation of mechanical energy, was examined in magnesium alloys of AZ31 and AZ61 type. These alloys have different contents of the main alloying elements and it is expected that they will have a significant impact on the measured course of amplitude dependencies of Internal Damping. Dependence of Internal Damping on amplitude was measured on test specimens after homogenization annealing without plastic deformation of the material and after different degrees of plastic deformation to determine the critical strain amplitude.
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Comparison of temperature dependence of Internal Damping of selected magnesium alloys
Production Engineering Archives, 2019Co-Authors: Tatiana Oršulová, Peter Palček, Milan UhríčikAbstract:Abstract The research is focused on the study of the temperature dependence of the Internal Damping of selected magnesium alloys with different contents of aluminium - AZ31 and AZ61. These alloys are currently widely used in various types of industry, mainly in the automotive industry. It belongs to a group of materials called HIDAMETS because they have excellent Damping properties. The Internal Damping of the samples was measured on a unique ultrasonic device constructed at Žilina University in Žilina. Specimens were measured at baseline in the temperature range from 25 °C to 400 °C. Changes in Internal Damping caused by varying aluminium contents in investigated alloys were noted. As the aluminium content increases, maximum Internal Damping is achieved due to the formation, growth and subsequent dissolution of the continuous precipitate in the microstructure.
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Changes in Internal Damping of selected types of austenitic stainless steels
Transportation Research Procedia, 2019Co-Authors: Tatiana Oršulová, Peter Palček, Milan Uhríčik, M. RoszakAbstract:Abstract The paper is focused on Internal Damping of three different types of austenitic stainless steels- exactly AISI 304, AISI 316L and AISI 316Ti. There was observed temperature dependence of Internal Damping of mentioned steels; each specimen was measured in a temperature range of 25 °C to 400 °C. The measurements were performed on samples in their initial state and in the state after recrystallization annealing. Correct interpreting of the changes in Internal Damping can bring a lot of important information about the changes taking place in the structure of the materials. Temperature changes allow the study of precipitation processes, recrystallization and the dissolution processes of some structural components.
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Analysis of dependence of Internal Damping on temperature of austenitic steels AISI 304 and AISI 316L
Transportation Research Procedia, 2019Co-Authors: Milan Uhríčik, Tatiana Oršulová, Peter Palček, Monika Oravcová, Patrícia HanusováAbstract:Abstract The article is focused on the analysis of dependence of Internal Damping on temperature of austenitic steels. The ability of a solid to irreversibly disperse energy under mechanical stress is called the Internal Damping. The time required to achieve the equilibrium deformation value is determined by various processes associated with the reallocation of atoms, magnetic moments and the temperature of the solid subjected to external stresses. Measurement of Internal Damping dependence on temperature was performed on austenitic steels AISI 304 and AISI 316L, in the initial state and after the deformation. Those materials are the most important group of corrosion-resistant metallic materials, which are very often used in industrial. Significant future growth is foreseen in the use of stainless steel for key structural components in automotive construction. Due to its unique mechanical properties, stainless steel can add an extra dimension of passenger safety, especially in the way that a large part of the energy produced in a collision is absorbed as the material deforms under impact. This property is already put to good effect in the design of modern large passenger vehicles such as buses, but the future potential in all types of road vehicle is immense (www.worldstainless.org).
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Temperature dependent measurement of Internal Damping of austenitic stainless steels
MATEC Web of Conferences, 2018Co-Authors: Monika Oravcová, Peter Palček, Mária Chalupová, Milan UhríčikAbstract:This article presents an analysis of the Internal Damping changes depending on the temperature of the austenitic stainless steels. The measurement of Internal Damping has a great meaning in investigation and evaluation of microplasticity and fatigue processes in metals. In experimental measurements only resonance method was used, which is based on continuous excitation of oscillations of the specimen and the entire apparatus vibrates at a frequency which is near to the resonance. These mechanisms have been studied by ultrasonic resonant apparatus. During the Internal Damping measurement of austenitic stainless steel it was found that the steels had characterized peak around the temperature of 100 °C and the backward measurement, by cooling down the sample, does not create any peak.
R Fougeres - One of the best experts on this subject based on the ideXlab platform.
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a dislocation model for Internal Damping due to the thermal expansion mismatch between matrix and particles in microheterogeneous materials
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 1993Co-Authors: Alain Vincent, G. Lormand, C Girard, X Zhou, R FougeresAbstract:Abstract A transient low frequency Internal Damping, called δ T , has been observed in various aluminium-based microheterogeneous materials (Al-12.8wt.%Si alloy containing large silicon particles, Al/12 vol.%SiC, Al-7075 alloy/15 vol.%SiC). On cooling δ T is characterized by a low temperature broad poorly fined maximum. Moreover, δ T increases with increasing the cooling rate and decreasing the frequency. It is shown that the observed phenomena are linked with the Internal stresses owing to the thermal expansion mismatch between particles and matrix. Finally, a model based on the movements of dislocations in the vicinity of the interface particle-matrix is suggested to explain the experimental features of δ T .
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Internal Damping effects due to the thermal expansion mismatch between aluminium and silicon in an Al 11.8 %Si alloy
Journal de Physique III, 1992Co-Authors: X Zhou, R Fougeres, A. VincentAbstract:In order to study the behaviour of the interface between particle and matrix, low frequency Internal Damping (I.D.) has been investigated with a torsion pendulum in an Al 11.8 wt%Si alloy containing large silicon particles with sizes up to 10 μm. The I.D. spectra are different on heating and on cooling the specimen. They exhibit a broad poorly defined maximum situated around 240 K on heating and 190 K on cooling, and a high temperature background on which a peak centered around 485 K seems to be superposed. Moreover, I.D. is increased over the whole temperature range 100-550 K as the heating or cooling rate, $|\dot{T}|$, is increased, or the oscillation frequency of the pendulum is decreased. The analysis of the experimental results is focused on the temperature rate dependent contribution δT that is shown to be linked with the Internal stresses induced by the difference in the coefficients of thermal expansion (CTE) of the silicon particles and the aluminium matrix. A model is outlined to describe δT in terms of emission or movement of dislocations that could be induced by the variation of thermal stresses during the I.D. spectrum measurement. A linear relationship between δT and the temperature rate is derived from the model and this appears to be approximately followed by the experimental data. The other contributions to I.D. are discussed in terms of grain boundary sliding, lattice dislocation movements and diffusional stress relaxation around Si particles.
Toshio Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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Forced oscillations of a rotating shaft with nonlinear spring characteristics and Internal Damping (1/2 order subharmonic oscillations and entrainment)
Nonlinear Dynamics, 1993Co-Authors: Yukio Ishida, Toshio YamamotoAbstract:Nonlinear forced oscillations of a rotating shaft with nonlinear spring characteristics and Internal Damping are studied. In particular, entrainment phenomena at the critical speeds of 1/2 order subharmonic oscillations of forward and backward whirling modes are investigated. A self-excited oscillation appears in the wide range above the major critical speed. The amplitude of this oscillation reaches a limit value and then a self-sustained oscillation occurs. In the vicinity of a 1/2 order subharmonic oscillation of a forward whirling mode, a self-excited oscillation is entrained by a subharmonic oscillation. In the vicinity of a 1/2 order subharmonic oscillation of a backward whirling mode, either a self-excited oscillation or a subharmonic oscillation occurs.
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Forced oscillations of a rotating shaft with nonlinear spring characteristics and Internal Damping (1/2 order subharmonic oscillations and entrainment)
Nonlinear Dynamics, 1993Co-Authors: Yukio Ishida, Toshio YamamotoAbstract:Nonlinear forced oscillations of a rotating shaft with nonlinear spring characteristics and Internal Damping are studied. In particular, entrainment phenomena at the critical speeds of 1/2 order subharmonic oscillations of forward and backward whirling modes are investigated. A self-excited oscillation appears in the wide range above the major critical speed. The amplitude of this oscillation reaches a limit value and then a self-sustained oscillation occurs. In the vicinity of a 1/2 order subharmonic oscillation of a forward whirling mode, a self-excited oscillation is entrained by a subharmonic oscillation. In the vicinity of a 1/2 order subharmonic oscillation of a backward whirling mode, either a self-excited oscillation or a subharmonic oscillation occurs. Experiments were made by an elastic rotating shaft with a disc. Nonlinearity in its restoring force was due to an angular clearance of a bearing and Internal Damping was due to friction between the shaft and an inner ring of the bearing. A self-excited oscillation was observed in the range above the major critical speed and this self-excited oscillation was entrained by a 1/2 order subharmonic oscillation of a forward whirling mode.
