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This paper proposes using neutral axis locations to monitor and quantify the prestress force in post-tensioned precast segmental beams. Strain measurements are used to obtain the neutral axis locations of specific cross-sections of the precast prestressed segmental beams, based on the plane–remains–plane and linear strain distribution assumption. A theoretical calculation method based on the static equilibrium of a specific cross-section is developed to calculate the prestress force in segmental beams based on the neutral axis location. To verify the accuracy of the proposed method, a post-tensioned prestressed segmental beam is built and tested in the laboratory. A corresponding high-fidelity finite element model is also developed based on the beam design and material properties. Experimental studies and numerical simulations are conducted to verify the feasibility and accuracy of the proposed method in quantifying the prestress force in precast segmental beams. Both experimental and numerical results demonstrate that the proposed method can reliably estimate the prestress force, which can be used to monitor the prestress force loss in post-tensioned structures.

High voltage switches are equipment that allow or block the electricity flow from one point to another. This paper presents an experimental approach, focused on the analysis of mechanical vibration applied in the maneuvering process of the switches. In this study, a maneuvering process was reproduced as it is done in industry, that is, free from vibration; then, the proposal to use mechanical vibration as an alternative aid to increase maneuvering process was tested, using the system proposed by patent BR 10 2013 020198 7. The quantitative parameters analyzed in this study are: vibration frequencies that provides torque relief for opening / closing maneuver, camshaft torque in the maneuvers, bolt torque, mechanical stress and deformation from different parts of the switch structure. In the present work, the obtained data suggests that harmonic mechanical vibration provides technological advances for the disconnecting switch system, such as, the increase of opening and closing maneuvering capabilities. It was also found that mechanical vibration does not affect the structure for the vibration requirements adopted during a survey. Thus, the quality of closure presents positive advances with the use of harmonic mechanical vibration, validating a solution proposed in the patent BR 10 2013 020198 7.

High voltage switches are equipment that allow or block the electricity flow from one point to another. This paper presents an experimental approach, focused on the analysis of mechanical vibration applied in the maneuvering process of the switches. In this study, a maneuvering process was reproduced as it is done in industry, that is, free from vibration; then, the proposal to use mechanical vibration as an alternative aid to increase maneuvering process was tested, using the system proposed by patent BR 10 2013 020198 7. The quantitative parameters analyzed in this study are: vibration frequencies that provides torque relief for opening / closing maneuver, camshaft torque in the maneuvers, bolt torque, mechanical stress and deformation from different parts of the switch structure. In the present work, the obtained data suggests that harmonic mechanical vibration provides technological advances for the disconnecting switch system, such as, the increase of opening and closing maneuvering capabilities. It was also found that mechanical vibration does not affect the structure for the vibration requirements adopted during a survey. Thus, the quality of closure presents positive advances with the use of harmonic mechanical vibration, validating a solution proposed in the patent BR 10 2013 020198 7.

High voltage switches are equipment that allow or block the electricity flow from one point to another. This paper presents an experimental approach, focused on the analysis of mechanical vibration applied in the maneuvering process of the switches. In this study, a maneuvering process was reproduced as it is done in industry, that is, free from vibration; then, the proposal to use mechanical vibration as an alternative aid to increase maneuvering process was tested, using the system proposed by patent BR 10 2013 020198 7. The quantitative parameters analyzed in this study are: vibration frequencies that provides torque relief for opening / closing maneuver, camshaft torque in the maneuvers, bolt torque, mechanical stress and deformation from different parts of the switch structure. In the present work, the obtained data suggests that harmonic mechanical vibration provides technological advances for the disconnecting switch system, such as, the increase of opening and closing maneuvering capabilities. It was also found that mechanical vibration does not affect the structure for the vibration requirements adopted during a survey. Thus, the quality of closure presents positive advances with the use of harmonic mechanical vibration, validating a solution proposed in the patent BR 10 2013 020198 7.

High voltage switches are equipment that allow or block the electricity flow from one point to another. This paper presents an experimental approach, focused on the analysis of mechanical vibration applied in the maneuvering process of the switches. In this study, a maneuvering process was reproduced as it is done in industry, that is, free from vibration; then, the proposal to use mechanical vibration as an alternative aid to increase maneuvering process was tested, using the system proposed by patent BR 10 2013 020198 7. The quantitative parameters analyzed in this study are: vibration frequencies that provides torque relief for opening / closing maneuver, camshaft torque in the maneuvers, bolt torque, mechanical stress and deformation from different parts of the switch structure. In the present work, the obtained data suggests that harmonic mechanical vibration provides technological advances for the disconnecting switch system, such as, the increase of opening and closing maneuvering capabilities. It was also found that mechanical vibration does not affect the structure for the vibration requirements adopted during a survey. Thus, the quality of closure presents positive advances with the use of harmonic mechanical vibration, validating a solution proposed in the patent BR 10 2013 020198 7.

High voltage switches are equipment that allow or block the electricity flow from one point to another. This paper presents an experimental approach, focused on the analysis of mechanical vibration applied in the maneuvering process of the switches. In this study, a maneuvering process was reproduced as it is done in industry, that is, free from vibration; then, the proposal to use mechanical vibration as an alternative aid to increase maneuvering process was tested, using the system proposed by patent BR 10 2013 020198 7. The quantitative parameters analyzed in this study are: vibration frequencies that provides torque relief for opening / closing maneuver, camshaft torque in the maneuvers, bolt torque, mechanical stress and deformation from different parts of the switch structure. In the present work, the obtained data suggests that harmonic mechanical vibration provides technological advances for the disconnecting switch system, such as, the increase of opening and closing maneuvering capabilities. It was also found that mechanical vibration does not affect the structure for the vibration requirements adopted during a survey. Thus, the quality of closure presents positive advances with the use of harmonic mechanical vibration, validating a solution proposed in the patent BR 10 2013 020198 7.

Anew version of a steeply inclined pivoted bucket belt conveyor with slippage of the traction belts relative to the shells of the reels is proposed. The natural vibrations of the buckets in the course of travel, taking into account the total rigidity of the two joined belts and the planks clamped between them, are estimated. The resonant speed of the conveyor belts is determined and the coefficient of dynamism is found. © 2017, Springer Science+Business Media, LLC.

Anew version of a steeply inclined pivoted bucket belt conveyor with slippage of the traction belts relative to the shells of the reels is proposed. The natural vibrations of the buckets in the course of travel, taking into account the total rigidity of the two joined belts and the planks clamped between them, are estimated. The resonant speed of the conveyor belts is determined and the coefficient of dynamism is found. © 2017, Springer Science+Business Media, LLC.

Study of the vibration frequencies at different cutting conditions is an alternative to the use of impact hammer test for identification of natural frequencies of the machining structure and calculation of stability lobe diagrams. Vibration frequencies not only depend on the natural frequencies of the structure, but also they are dependent on the spindle speed, damping ratio of the structure and the depth of cut. Ignoring these additional parameters would lead to errors in identification of the natural frequencies of the system and considerable deviation of the calculated stability lobe diagrams from actual cutting tests. In this study modified Nyquist method is used to investigate the effects of spindle speed, depth of cut and damping ratio of the structure on vibration frequencies. The quality of frequency prediction is compared to linear and nonlinear time domain simulations and machining experiments., The research presented in this paper has been supported by InnKa project, an ERDF project. The contribution is greatly appreciated.

The atomic mass ratio of ca. 2 between deuterium and hydrogen is the highest for any pair of stable isotopes and results in significant and measurable H/D isotope effects in high temperature proton conductors containing these species. This paper discusses H/D isotope effects manifested in O-H/O-D vibration frequencies, the mobility of H+/D+ carriers, the kinetics of the electrochemical oxidation of H2/D2, the solubilities of H2O/D2O and, finally, the spontaneous electromotive force that appears across H2/D2 cells with proton conducting electrolytes. Comparable work on tritium-exchanged materials is also discussed. The results highlight the usefulness of isotope effects in the study of high temperature proton conductors.

We have developed an all-atomistic force field for a new class of halogen-free chelated orthoborate-phosphonium ionic liquids. The force field is based on an AMBER framework with determination of force field parameters for phosphorus and boron atoms, as well as refinement of several available parameters. The bond and angle force constants were adjusted to fit vibration frequency data derived from both experimental measurements and ab initio calculations. The force field parameters for several dihedral angles were obtained by fitting torsion energy profiles deduced from ab initio calculations. To validate the proposed force field parameters, atomistic simulations were performed for 12 ionic liquids consisting of tetraalkylphosphonium cations and chelated orthoborate anions. The predicted densities for neat ionic liquids and the [P-6,P-6,P-6,P-14][BOB] sample, with a water content of approximately 2.3-2.5 wt %, are in excellent agreement with available experimental data. The potential energy components of 12 ionic liquids were discussed in detail. The radial distribution functions and spatial distribution functions were analyzed and visualized to probe the microscopic ionic structures of these ionic liquids. There are mainly four high-probability regions of chelated orthoborate anions distributed around tetraalkylphosphonium cations in the first solvation shell, and such probability distribution functions are strongly influenced by the size of anions., QC 20140822

Using modified Nyquist contours, the dominant poles of the closed loop delay-differential equation for machining systems such as milling are identified. Contours with constant damping ratio of the dominant poles are constructed using this method. These contours are similar in shape to the stability lobes, but move upwards and to the right as the instability parameter increases. Additionally, it is possible to study the movement of the dominant poles to the right-hand side of the complex plane as the system becomes unstable by increasing the depth of cut at a constant spindle speed. The movement of the dominant pole is shown to be towards the right (unstable) and upward (higher vibration frequency) of the complex plane. In some cases, there would be a jump of vibration frequency due to the change of the lobe number. It is also shown that the damping ratio of the structure strongly affects both the vibration frequency and the damping ratio of the dominant poles in the closed loop system. Finally, in two milling experiments with two different spindle speeds and continuously increasing depth of cuts, vibration frequencies are measured and compared to the theoretical predictions. The measurements agree with the theoretical predictions, particularly in the unstable cutting conditions., InnKa

Using modified Nyquist contours, the dominant poles of the closed loop delay-differential equation for machining systems such as milling are identified. Contours with constant damping ratio of the dominant poles are constructed using this method. These contours are similar in shape to the stability lobes, but move upwards and to the right as the instability parameter increases. Additionally, it is possible to study the movement of the dominant poles to the right-hand side of the complex plane as the system becomes unstable by increasing the depth of cut at a constant spindle speed. The movement of the dominant pole is shown to be towards the right (unstable) and upward (higher vibration frequency) of the complex plane. In some cases, there would be a jump of vibration frequency due to the change of the lobe number. It is also shown that the damping ratio of the structure strongly affects both the vibration frequency and the damping ratio of the dominant poles in the closed loop system. Finally, in two milling experiments with two different spindle speeds and continuously increasing depth of cuts, vibration frequencies are measured and compared to the theoretical predictions. The measurements agree with the theoretical predictions, particularly in the unstable cutting conditions., InnKa

Using modified Nyquist contours, the dominant poles of the closed loop delay-differential equation for machining systems such as milling are identified. Contours with constant damping ratio of the dominant poles are constructed using this method. These contours are similar in shape to the stability lobes, but move upwards and to the right as the instability parameter increases. Additionally, it is possible to study the movement of the dominant poles to the right-hand side of the complex plane as the system becomes unstable by increasing the depth of cut at a constant spindle speed. The movement of the dominant pole is shown to be towards the right (unstable) and upward (higher vibration frequency) of the complex plane. In some cases, there would be a jump of vibration frequency due to the change of the lobe number. It is also shown that the damping ratio of the structure strongly affects both the vibration frequency and the damping ratio of the dominant poles in the closed loop system. Finally, in two milling experiments with two different spindle speeds and continuously increasing depth of cuts, vibration frequencies are measured and compared to the theoretical predictions. The measurements agree with the theoretical predictions, particularly in the unstable cutting conditions., CC BY-NC-ND 3.0The research presented in this paper has been supported by InnKa project, an ERDF project. The contribution is greatly appreciated., InnKa

Using modified Nyquist contours, the dominant poles of the closed loop delay-differential equation for machining systems such as milling are identified. Contours with constant damping ratio of the dominant poles are constructed using this method. These contours are similar in shape to the stability lobes, but move upwards and to the right as the instability parameter increases. Additionally, it is possible to study the movement of the dominant poles to the right-hand side of the complex plane as the system becomes unstable by increasing the depth of cut at a constant spindle speed. The movement of the dominant pole is shown to be towards the right (unstable) and upward (higher vibration frequency) of the complex plane. In some cases, there would be a jump of vibration frequency due to the change of the lobe number. It is also shown that the damping ratio of the structure strongly affects both the vibration frequency and the damping ratio of the dominant poles in the closed loop system. Finally, in two milling experiments with two different spindle speeds and continuously increasing depth of cuts, vibration frequencies are measured and compared to the theoretical predictions. The measurements agree with the theoretical predictions, particularly in the unstable cutting conditions., CC BY-NC-ND 3.0The research presented in this paper has been supported by InnKa project, an ERDF project. The contribution is greatly appreciated., InnKa

Using modified Nyquist contours, the dominant poles of the closed loop delay-differential equation for machining systems such as milling are identified. Contours with constant damping ratio of the dominant poles are constructed using this method. These contours are similar in shape to the stability lobes, but move upwards and to the right as the instability parameter increases. Additionally, it is possible to study the movement of the dominant poles to the right-hand side of the complex plane as the system becomes unstable by increasing the depth of cut at a constant spindle speed. The movement of the dominant pole is shown to be towards the right (unstable) and upward (higher vibration frequency) of the complex plane. In some cases, there would be a jump of vibration frequency due to the change of the lobe number. It is also shown that the damping ratio of the structure strongly affects both the vibration frequency and the damping ratio of the dominant poles in the closed loop system. Finally, in two milling experiments with two different spindle speeds and continuously increasing depth of cuts, vibration frequencies are measured and compared to the theoretical predictions. The measurements agree with the theoretical predictions, particularly in the unstable cutting conditions., CC BY-NC-ND 3.0The research presented in this paper has been supported by InnKa project, an ERDF project. The contribution is greatly appreciated., InnKa

Using modified Nyquist contours, the dominant poles of the closed loop delay-differential equation for machining systems such as milling are identified. Contours with constant damping ratio of the dominant poles are constructed using this method. These contours are similar in shape to the stability lobes, but move upwards and to the right as the instability parameter increases. Additionally, it is possible to study the movement of the dominant poles to the right-hand side of the complex plane as the system becomes unstable by increasing the depth of cut at a constant spindle speed. The movement of the dominant pole is shown to be towards the right (unstable) and upward (higher vibration frequency) of the complex plane. In some cases, there would be a jump of vibration frequency due to the change of the lobe number. It is also shown that the damping ratio of the structure strongly affects both the vibration frequency and the damping ratio of the dominant poles in the closed loop system. Finally, in two milling experiments with two different spindle speeds and continuously increasing depth of cuts, vibration frequencies are measured and compared to the theoretical predictions. The measurements agree with the theoretical predictions, particularly in the unstable cutting conditions., CC BY-NC-ND 3.0The research presented in this paper has been supported by InnKa project, an ERDF project. The contribution is greatly appreciated., InnKa

Using modified Nyquist contours, the dominant poles of the closed loop delay-differential equation for machining systems such as milling are identified. Contours with constant damping ratio of the dominant poles are constructed using this method. These contours are similar in shape to the stability lobes, but move upwards and to the right as the instability parameter increases. Additionally, it is possible to study the movement of the dominant poles to the right-hand side of the complex plane as the system becomes unstable by increasing the depth of cut at a constant spindle speed. The movement of the dominant pole is shown to be towards the right (unstable) and upward (higher vibration frequency) of the complex plane. In some cases, there would be a jump of vibration frequency due to the change of the lobe number. It is also shown that the damping ratio of the structure strongly affects both the vibration frequency and the damping ratio of the dominant poles in the closed loop system. Finally, in two milling experiments with two different spindle speeds and continuously increasing depth of cuts, vibration frequencies are measured and compared to the theoretical predictions. The measurements agree with the theoretical predictions, particularly in the unstable cutting conditions., CC BY-NC-ND 3.0The research presented in this paper has been supported by InnKa project, an ERDF project. The contribution is greatly appreciated., InnKa

Using modified Nyquist contours, the dominant poles of the closed loop delay-differential equation for machining systems such as milling are identified. Contours with constant damping ratio of the dominant poles are constructed using this method. These contours are similar in shape to the stability lobes, but move upwards and to the right as the instability parameter increases. Additionally, it is possible to study the movement of the dominant poles to the right-hand side of the complex plane as the system becomes unstable by increasing the depth of cut at a constant spindle speed. The movement of the dominant pole is shown to be towards the right (unstable) and upward (higher vibration frequency) of the complex plane. In some cases, there would be a jump of vibration frequency due to the change of the lobe number. It is also shown that the damping ratio of the structure strongly affects both the vibration frequency and the damping ratio of the dominant poles in the closed loop system. Finally, in two milling experiments with two different spindle speeds and continuously increasing depth of cuts, vibration frequencies are measured and compared to the theoretical predictions. The measurements agree with the theoretical predictions, particularly in the unstable cutting conditions., InnKa

Using modified Nyquist contours, the dominant poles of the closed loop delay-differential equation for machining systems such as milling are identified. Contours with constant damping ratio of the dominant poles are constructed using this method. These contours are similar in shape to the stability lobes, but move upwards and to the right as the instability parameter increases. Additionally, it is possible to study the movement of the dominant poles to the right-hand side of the complex plane as the system becomes unstable by increasing the depth of cut at a constant spindle speed. The movement of the dominant pole is shown to be towards the right (unstable) and upward (higher vibration frequency) of the complex plane. In some cases, there would be a jump of vibration frequency due to the change of the lobe number. It is also shown that the damping ratio of the structure strongly affects both the vibration frequency and the damping ratio of the dominant poles in the closed loop system. Finally, in two milling experiments with two different spindle speeds and continuously increasing depth of cuts, vibration frequencies are measured and compared to the theoretical predictions. The measurements agree with the theoretical predictions, particularly in the unstable cutting conditions., InnKa

Using modified Nyquist contours, the dominant poles of the closed loop delay-differential equation for machining systems such as milling are identified. Contours with constant damping ratio of the dominant poles are constructed using this method. These contours are similar in shape to the stability lobes, but move upwards and to the right as the instability parameter increases. Additionally, it is possible to study the movement of the dominant poles to the right-hand side of the complex plane as the system becomes unstable by increasing the depth of cut at a constant spindle speed. The movement of the dominant pole is shown to be towards the right (unstable) and upward (higher vibration frequency) of the complex plane. In some cases, there would be a jump of vibration frequency due to the change of the lobe number. It is also shown that the damping ratio of the structure strongly affects both the vibration frequency and the damping ratio of the dominant poles in the closed loop system. Finally, in two milling experiments with two different spindle speeds and continuously increasing depth of cuts, vibration frequencies are measured and compared to the theoretical predictions. The measurements agree with the theoretical predictions, particularly in the unstable cutting conditions., InnKa

Boronic acids (R-B(OH)2) are a family of molecules that have found a large number of applications in materials science. In contrast, boronate anions (R-B(OH)3 -) have hardly been used so far for the preparation of novel materials. Here, a new crystalline phase involving a boronate ligand is described, Ca[C4H9-B(OH) 3]2, which is then used as a basis for the establishment of the spectroscopic signatures of boronates in the solid state. The phase was characterized by IR and multinuclear solid-state NMR spectroscopy ( 1H, 13C, 11B and 43Ca), and then modeled by periodic DFT calculations. Anharmonic OH vibration frequencies were calculated as well as NMR parameters (by using the Gauge Including Projector Augmented Wave - GIPAW - method). These data allow relationships between the geometry around the OH groups in boronates and the IR and 1HNMR spectroscopic data to be established, which will be key to the future interpretation of the spectra of more complex organic-inorganic materials containing boronate building blocks. Boronate ligands in materials: A combined experimental/computational approach is used to define the IR and NMR spectroscopic signatures of boronate ligands in the solid state. OH stretching frequencies and 1H chemical shifts can now be related to the local environments around the OH groups (see figure). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cílem diplomové práce bylo navrhnout přibližný model cisterny, který by umožnil vyšetřit dynamické vlastnosti konstrukce. Model vznikal od jednoduchých analytických řešení po složité vytvořené pomocí metody konečných prvků. Kmitavé vlastnosti se vyšetřovali pomocí simulace přejezdu překážek v určených rychlostech. Pomocí vyhodnocených odezev se usuzovalo na rezonanční oblasti., The main purpose of this thesis is to suggest a casual tank model, which would help to solve dynamic features of construction. The model came from simple analytic solutions, and a method of final components was used when it became complicated. A simulation of vibrating features was used by placing obstructions in the gears. It was reasoned on the turned part by help of evalution responses., Katedra dopravních prostředků a diagnostiky, Diplomantka ve své prezentaci podrobně seznámila zkušební komisi s problematikou spojenou s dynamickým model třínápravové cisterny. Diplomantka odpověděla správně i věcně na všechny otázky položené při obhajobě., Dokončená práce s úspěšnou obhajobou

Prediction and monitoring of vibrations from rock blasting is of practical importance. Damage to rock tunnels caused by blasting is fundamentally different to that of conventional buildings. Different damage mechanisms are discussed as well as methods to monitor the development of cracks by analysis of frequency content. For the assessment of the damage potential it is essential to understand wave propagation in rock and the dynamic response of cavities to vibration excitation. Vibration frequency and wavelength in relation to the size of the cavity are important parameters. Vibration amplification of a circular tunnel to a plane wave is analyzed and guidelines given for practical design applications. Filtering the vibration signal, which is often required in national standards, car. give misleading results for tunnels in rock., QC 20120109

New in situ Raman and synchrotron X-ray diffraction data (between 300 and 400 K) in conjunction with separate temperature-dependent Raman data (between 7 and 400 K) are presented. The low-frequency Raman spectra show good agreement with theoretical values obtained previously using periodic DFT calculations. The temperature-dependent spectra reveal the presence of significant anharmonicity of librational modes neither predicted theoretically nor noted in previous experiments. The splitting of the internal deformation mode 2 (of E symmetry in the free ion) decreases continuously with increasing temperature, but drops abruptly at the first-order orthorhombic to hexagonal phase transition observed at 381 K. The temperature dependence of the linewidth of the internal deformation mode 2 reveals coupling to reorientational motions of the borohydride ion in the orthorhombic phase. The thermal evolution of both crystal structure and vibration frequencies agree with the phase diagram suggested by the Landau theory.

© 2017 Springer Science+Business Media, LLC A discrete layered damping model of a multilayer plate at small displacements and deformations, with account of the internal damping of layers according to the Thompson–Kelvin–Voight model, is presented. Based on the equations derived, an analytical solution to the static deformation problem for single-layer rectangular plate hinge-supported along its contour and subjected of a uniformly distributed pressure applied to one of its boundary planes is obtained. Its convergence to the three-dimensional solution is analyzed in relation to the dimension of mesh in the thickness direction of the plate. It is found that, for thin plates, the dimension of the problem formulated can be reduced on the basis of simplified hypotheses applied to each layer. Аn analytical solutions is also constructed for the forced vibrations of two- and three-layer rectangular plates hinged in the opening of an absolutely stiff dividing wall upon transmission of a monoharmonic sound wave through them. It was assumed that the dividing wall is situated between two absolutely stiff barriers; one of them, owing to the harmonic vibration with a given displacement amplitude of the plate, forms an incident sound wave, and the other is stationary and is coated by a energy-absorbing material with high damping properties. Behavior of the acoustic media in spaces between the deformable plate and the barriers is described by the classical wave equations based on the model of an ideal compressible fluid. To describe the process of dynamic deformation of the energy-absorbing coating of the fixed barrier, two-dimensional equations of motion are derived based on the model of a transversely soft layer, a linear approximation of displacement fields in the thickness direction of the coating, and the account of damping properties of its material by using the hysteresis model. The effect of physical and mechanical parameters of the mechanical system considered and of frequ

© 2017 Springer Science+Business Media, LLC A discrete layered damping model of a multilayer plate at small displacements and deformations, with account of the internal damping of layers according to the Thompson–Kelvin–Voight model, is presented. Based on the equations derived, an analytical solution to the static deformation problem for single-layer rectangular plate hinge-supported along its contour and subjected of a uniformly distributed pressure applied to one of its boundary planes is obtained. Its convergence to the three-dimensional solution is analyzed in relation to the dimension of mesh in the thickness direction of the plate. It is found that, for thin plates, the dimension of the problem formulated can be reduced on the basis of simplified hypotheses applied to each layer. Аn analytical solutions is also constructed for the forced vibrations of two- and three-layer rectangular plates hinged in the opening of an absolutely stiff dividing wall upon transmission of a monoharmonic sound wave through them. It was assumed that the dividing wall is situated between two absolutely stiff barriers; one of them, owing to the harmonic vibration with a given displacement amplitude of the plate, forms an incident sound wave, and the other is stationary and is coated by a energy-absorbing material with high damping properties. Behavior of the acoustic media in spaces between the deformable plate and the barriers is described by the classical wave equations based on the model of an ideal compressible fluid. To describe the process of dynamic deformation of the energy-absorbing coating of the fixed barrier, two-dimensional equations of motion are derived based on the model of a transversely soft layer, a linear approximation of displacement fields in the thickness direction of the coating, and the account of damping properties of its material by using the hysteresis model. The effect of physical and mechanical parameters of the mechanical system considered and of frequ

© 2018, Pleiades Publishing, Ltd. The propagation of a stationary acoustic wave through an infinite thin plate stiffened on two sides by a system of absolutely rigid, crossed ribs and located between two absolutely rigid barriers. It is assumed that the plate and the ribs evenly distributed along rectangular Cartesian axes are connected through elastic spacers (supports) without slip. The dynamic deformation of the plate is described by the linearized Kirchhoff–Love equations of the classical theory of plates, the dynamic deformation of the spacers is described by two-dimensional and one-dimensional relations based on linear approximations of displacements of points of the coating and spacers along the thickness and taking into account only transverse compression and transverse shear, and the motion of acoustic media by the well-known wave equations. The solution of the problem is obtained using the Ritz method. The constructed solution was used to investigate how the physico-mechanical and geometric parameters of the mechanical system and the frequency of acoustic waves incident on the plate influence the sound-insulating parameters and the stress–strain state of the plate.