Forced Vibration Of The Hydro-viscoelastic (hydro-elastıc) Systems Consisting Of The Viscoelastic (elastic) Plate, Compressible Viscous Fluid And Rigid Wall (review)

Konferans Bildirisi-- İstanbul Teknik Üniversitesi, Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2017Conference Paper -- İstanbul Technical University, Theoretical and Applied Mechanical Turkish National Committee, 2017This paper gives review of the investigations related to the forced vibration of the hydro-viscoelastic as well as of the hydro-elastic systems consisting of elastic or viscoelastic plate, compressible viscous fluid and rigid wall. The sketch of this system in some particular case is given in Fig. 1. The investigations carried out for the fluid loading cases are also reviewed and under this review the main attention is focused on the studies made by authors. Note that in these investigations the motion of the plate is written by employing three-dimensional linearized equations of wave propagation in elastic and viscoelastic bodies with initial stresses, however the equations of flow of the compressible viscous fluid is described by employing the linearized Navier-Stokes equations. It is assumed that the plane strain state in the plane occurs in the plate and the fluid flow is plane-parallel one and suppose that the plate occupies the region Within these assumptions we write the field equations for the constituents of the system in the case where the plate material is purely elastic

Dispersion Of Lamb Waves Propagating In A Plate Made Of Viscoelastic Material

Konferans Bildirisi-- İstanbul Teknik Üniversitesi, Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2017Conference Paper -- İstanbul Technical University, Theoretical and Applied Mechanical Turkish National Committee, 2017Lineer viskoelastik malzemelerden oluşan plakalarda Lamb dalgalarının dispersyonu incelenmiştir. Araştırmalar, lineer viskoelastik teorisinin kesin denklemlerini uygulayarak yapılmıştır. Dispersyon denklemi, malzemenin herediter operatörünün keyfi türü için elde ettikten sonra incelenen dalgaların dispersyonu üzerine sayısal sonuçlar elde etmek için bir çözüm algoritması geliştirilmiştir. Farklı atenüasyon durumları için dispersyon eğrileri elde edilmiş ve malzemenin viskozitesinin etkisi, elastik sabitlerle karakterize eden reolojik parametreler, yani, Q viskoelastik malzemenin karakteristik akma süresi, d viskoelastik malzemenin mekanik sabitlerinin uzun vadeli değeri ve α viskoelastik malzemenin deformasyonun başlangıç durumu etrafındaki mekanik davranışı aracılığıyla incelenemiştir. Malzemenin viskoelastisitesini Rabotnov'un kısmi eksponansiyel operatörü’nü uygulayarak sayısal sonuçlar sunularak tartışılmıştır. Özellikle, reolojik parametrelerin, incelenen plakada yayılan Lamb dalgalarının dispersyonuna nasıl etkilediği tespit edilmiştir.Dispersion of the Lamb waves propagating in a plate made of viscoelastic material is investigated. The investigations are made by utilizing the exact equations of the theory of linear viscoelasticity. The dispersion equation is obtained for an arbitrary type of hereditary operator of the materials of the constituents and a solution algorithm is developed for obtaining numerical results. Dispersion curves is presented for certain attenuation cases and the influence of the viscosity of the material is studied through the rheological parameters which characterize the characteristic creep time, long-term values and the mechanical behavior of the viscoelastic material around the initial state of the deformation. Numerical results are presented and discussed for the case where the viscoelasticity of the materials is described through fractional-exponential operators by Rabotnov. In particular, how the rheological parameters influence on the dispersion of the Lamb waves are established

Dispersion Of Lamb Waves Propagating In A Plate Made Of Viscoelastic Material

Konferans Bildirisi-- İstanbul Teknik Üniversitesi, Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2017Conference Paper -- İstanbul Technical University, Theoretical and Applied Mechanical Turkish National Committee, 2017Lineer viskoelastik malzemelerden oluşan plakalarda Lamb dalgalarının dispersyonu incelenmiştir. Araştırmalar, lineer viskoelastik teorisinin kesin denklemlerini uygulayarak yapılmıştır. Dispersyon denklemi, malzemenin herediter operatörünün keyfi türü için elde ettikten sonra incelenen dalgaların dispersyonu üzerine sayısal sonuçlar elde etmek için bir çözüm algoritması geliştirilmiştir. Farklı atenüasyon durumları için dispersyon eğrileri elde edilmiş ve malzemenin viskozitesinin etkisi, elastik sabitlerle karakterize eden reolojik parametreler, yani, Q viskoelastik malzemenin karakteristik akma süresi, d viskoelastik malzemenin mekanik sabitlerinin uzun vadeli değeri ve α viskoelastik malzemenin deformasyonun başlangıç durumu etrafındaki mekanik davranışı aracılığıyla incelenemiştir. Malzemenin viskoelastisitesini Rabotnov'un kısmi eksponansiyel operatörü’nü uygulayarak sayısal sonuçlar sunularak tartışılmıştır. Özellikle, reolojik parametrelerin, incelenen plakada yayılan Lamb dalgalarının dispersyonuna nasıl etkilediği tespit edilmiştir.Dispersion of the Lamb waves propagating in a plate made of viscoelastic material is investigated. The investigations are made by utilizing the exact equations of the theory of linear viscoelasticity. The dispersion equation is obtained for an arbitrary type of hereditary operator of the materials of the constituents and a solution algorithm is developed for obtaining numerical results. Dispersion curves is presented for certain attenuation cases and the influence of the viscosity of the material is studied through the rheological parameters which characterize the characteristic creep time, long-term values and the mechanical behavior of the viscoelastic material around the initial state of the deformation. Numerical results are presented and discussed for the case where the viscoelasticity of the materials is described through fractional-exponential operators by Rabotnov. In particular, how the rheological parameters influence on the dispersion of the Lamb waves are established

Forced Vibration Of The Hydro-viscoelastic (hydro-elastıc) Systems Consisting Of The Viscoelastic (elastic) Plate, Compressible Viscous Fluid And Rigid Wall (review)

Konferans Bildirisi-- İstanbul Teknik Üniversitesi, Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2017Conference Paper -- İstanbul Technical University, Theoretical and Applied Mechanical Turkish National Committee, 2017This paper gives review of the investigations related to the forced vibration of the hydro-viscoelastic as well as of the hydro-elastic systems consisting of elastic or viscoelastic plate, compressible viscous fluid and rigid wall. The sketch of this system in some particular case is given in Fig. 1. The investigations carried out for the fluid loading cases are also reviewed and under this review the main attention is focused on the studies made by authors. Note that in these investigations the motion of the plate is written by employing three-dimensional linearized equations of wave propagation in elastic and viscoelastic bodies with initial stresses, however the equations of flow of the compressible viscous fluid is described by employing the linearized Navier-Stokes equations. It is assumed that the plane strain state in the plane occurs in the plate and the fluid flow is plane-parallel one and suppose that the plate occupies the region Within these assumptions we write the field equations for the constituents of the system in the case where the plate material is purely elastic

Dynamics of pre-strained bi-material elastic systems: linearized three-dimensional approach

This book deals with dynamics of pre-stressed or pre-strained bi-material elastic systems consisting of stack of pre-stressed layers, stack of pre-stressed layers and pre-stressed half space (or half plane), stack of pre-stressed layers as well as absolute rigid foundation, pre-stressed compound solid and hollow cylinders and pre-stressed sandwich hollow cylinders. The problems considered in the book relate to the dynamics of a moving and oscillating moving load, forced vibration caused by linearly located or point located time-harmonic forces acting to the foregoing systems. Moreover, a considerable part of the book relate to the problems regarding the near surface, torsional and axisymmetric longitudinal waves propagation and dispersion in the noted above bi-material elastic systems. The book carries out the investigations within the framework of the piecewise homogeneous body model with the use of the Three-Dimensional Linearized Theory of Elastic Waves in Initially Stressed Bodies

Vibration of a Two-Layer “Metal+PZT” Plate Contacting with Viscous Fluid

The present work investigates the mechanically forced vibration of the hydro-elasto-piezoelectric system consisting of a two-layer plate “elastic+PZT”, a compressible viscous fluid, and a rigid wall. It is assumed that the PZT (piezoelectric) layer of the plate is in contact with the fluid and time-harmonic linear forces act on the free surface of the elastic-metallic layer. This study is valuable because it considers for the first time the mechanical vibration of the metal+piezoelectric bilayer plate in contact with a fluid. It is also the first time that the influence of the volumetric concentration of the constituents on the vibration of the hydro-elasto-piezoelectric system is studied. Another value of the present work is the use of the exact equations and relations of elasto-electrodynamics for elastic and piezoelectric materials to describe the motion of the plate layers within the framework of the piecewise homogeneous body model and the use of the linearized Navier-Stokes equations to describe the flow of the compressible viscous fluid. The plane-strain state in the plate and the plane flow in the fluid take place. For the solution of the corresponding boundary-value problem, the Fourier transform is used with respect to the spatial coordinate on the axis along the laying direction of the plate. The analytical expressions of the Fourier transform of all the sought values of each component of the system are determined. The origins of the searched values are determined numerically, after which numerical results on the stress on the fluid and plate interface planes are presented and discussed. These results are obtained for the case where PZT-2 is chosen as the piezoelectric material, steel and aluminum as the elastic metal materials, and Glycerin as the fluid. Analysis of these results allows conclusions to be drawn about the character of the problem parameters on the frequency response of the interfacial stress. In particular, it was found that after a certain value of the vibration frequency, the presence of the metal layer in the two-layer plate led to an increase in the absolute values of the above interfacial stress. © 2023 Tech Science Press. All rights reserved

Calculation and 3D analyses of ERR in the band crack front contained in a rectangular plate made of multilayered material

An investigation into the values of the Energy Release Rate (ERR) at the band crack’s front in the rectangular plate made of multilayered composite material is carried out for the opening mode. The corresponding boundary-value problem is modelled by using threedimensional linear theory and solved numerically by using 3D FEM (Three Dimensional Finite Element Method). The main purpose of the current investigation is to study the influence of mechanical and geometrical parameters on the Energy Release Rate (ERR) at this crack front. The numerical results related to the ERR, and the effect of the mechanical and other problem parameters on the ERR are presented and discussed

Fonksiyonel Derecelendirilmiş Malzemeden Yapılmış İçi Boş Kürenin Torsiyonel Serbest Titreşiminin Analitik İncelenmesi

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2015Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2015Bu çalışmada, üst ve alt katmanı homojen-izotrop malzemeden, orta tabakası izotrop-fonksiyonel derecelendirilmiş malzemeden yapılmış üç tabakalı içi boş kürenin torsiyonel (burulma) doğal titreşimi, elastodinamiğin üç boyutlu kesin denklemleri çerçevesinde diskrit-analitik yöntemle incelenmiştir. Kürenin katmanları arasında ideal temas koşullarının sağlandığı kabul edilmektedir.In this study, torsional vibration of three-layered hollow sphere whose materials of upper and lower layers are homogeneous and isotropic and that of mid-layer is isotropic and functionally graded one, is investigated with utilizing discrete-analytical method within the three dimensional exact equations of elastodynamics. It is supposed that perfect contact conditions are valid on interfaces between the layers