scholarly journals Calculation of Wave Dispersion Curves in Multilayered Composite-Metal Plates

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Ameneh Maghsoodi ◽  
Abdolreza Ohadi ◽  
Mojtaba Sadighi
Keyword(s):  
Transfer Matrix ◽  
Equations Of Motion ◽  
Wave Dispersion ◽  
Dispersion Curves ◽  
Metal Plate ◽  
Material Symmetry ◽  
Major Purpose ◽  
Characteristic Equations ◽  
Multilayered Composite ◽  
Metal Plates

The major purpose of this paper is the development of wave dispersion curves calculation in multilayered composite-metal plates. At first, equations of motion and characteristic equations for the free waves on a single-layered orthotropic plate are presented. Since direction of wave propagation in composite materials is effective on equations of motion and dispersion curves, two different cases are considered: propagation of wave along an axis of material symmetry and along off-axes of material symmetry. Then, presented equations are extended for a multilayered orthotropic composite-metal plate using the transfer matrix method in which a global transfer matrix may be extracted which relates stresses and displacements on the top layer to those on the bottom one. By satisfying appropriate boundary conditions on the outer boundaries, wave characteristic equations and then dispersion curves are obtained. Moreover, presented equations may be applied to other materials such as monoclinic, transversely isotropic, cubic, and isotropic materials. To verify the solution procedure, a number of numerical illustrations for a single-layered orthotropic and double-layered orthotropic-metal are presented.

A Point-Focus PVDF Transducer for Lamb Wave Measurements

2002 ◽  
Vol 18 (1) ◽  
pp. 29-33
Author(s):  
Yung-Chun Lee ◽  
Yi Fan Tein ◽  
Yu Yi Chao
Keyword(s):  
Lamb Wave ◽  
Acoustic Waves ◽  
Lamb Waves ◽  
Experimental Testing ◽  
Spherical Shape ◽  
Wave Dispersion ◽  
Dispersion Curves ◽  
Pvdf Film ◽  
Wave Measurements ◽  
Metal Plates

ABSTRACTThis paper reports the development of a point-focused PVDF transducer with a large aperture surface and its application on measuring Lamb wave dispersion curves. The point-focused transducer is constructed by forcing a piezoelectric PVDF film into a concave spherical shape. The acoustic waves radiated from the PVDF film are then focused into a point without using any acoustic lens. Similar to its line-focused counterpart, the point-focused transducer is capable of measuring dispersion curves of lamb waves provided its aperture angle is large enough. To verify this, experimental testing is carried out on several thin metal plates and good measurement results are observed. Future improvements and applications on the transducer will be addressed.

Inversion of Rayleigh wave dispersion curves via adaptive GA and nested DLS

2019 ◽  
Vol 218 (1) ◽  
pp. 547-559 ◽  
Author(s):  
Yuhang Lei ◽  
Hongyan Shen ◽  
Xinxin Li ◽  
Xin Wang ◽  
Qingchun Li
Keyword(s):  
Rayleigh Wave ◽  
Wave Dispersion ◽  
Dispersion Curves ◽  
Rayleigh Wave Dispersion

Analysis on Metal Plate Connection Property of Larch Dimension Lumber

2012 ◽  
Vol 174-177 ◽  
pp. 2170-2175
Author(s):  
Rong Jun Zhao ◽  
Jun Zhen Zhang ◽  
Hai Bin Zhou ◽  
Ben Hua Fei
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Metal Plate ◽  
Seismic Structure ◽  
Performance Parameters ◽  
Metal Plates ◽  
Dimension Lumber ◽  
Design Value ◽  
Plate Connection ◽  
Ductility Ratio

In this study, Larix gemilinii and metal plate were selected as the main materials. According to GB5005-2003, the connection properties of tension-splice joint and larch wood were investigated. The results showed that the elastic modulus of Larix gemilinii was not affected by the performance parameters of tension-splice joint greatly and three kinds of failure modes were introduced. Besides the design value for the ultimate bearing capacity of Larix gemilinii and the design value for the ultimate tensile bearing capacity of the metal plates were determined. A conservative calculation method for ductility ratio of metal plates was proposed. The ductility ratio of the metal plate connected joint changed with the construction modes, and the ductility ratio for metal plate parallel to the grain (more than 2.4) was obviously bigger than that of perpendicular to the grain, which complies with the requirements for ductility ratio in anti-seismic structure.

P- and S-wave velocity models from surface wave dispersion curves data transform

2017 ◽  
Author(s):  
Valentina Socco ◽  
Farbod Khosro Anjom ◽  
Cesare Comina ◽  
Daniela Teodor
Keyword(s):  
Surface Wave ◽  
Wave Velocity ◽  
Wave Dispersion ◽  
Dispersion Curves ◽  
S Wave ◽  
Surface Wave Dispersion ◽  
Velocity Models

A model study of elastic waves in a layered sphere

1967 ◽  
Vol 57 (5) ◽  
pp. 959-981
Author(s):  
Victor Gregson
Keyword(s):  
Surface Wave ◽  
Surface Waves ◽  
Elastic Waves ◽  
Wave Dispersion ◽  
Flat Space ◽  
Dispersion Curves ◽  
Body Waves ◽  
Surface Wave Dispersion ◽  
Steel Sphere ◽  
Long Wave

abstract Elastic waves produced by an impact were recorded at the surface of a solid 12.0 inch diameter steel sphere coated with a 0.3 inch copper layer. Conventional modeling techniques employing both compressional and shear piezoelectric transducers were used to record elastic waves for one millisecond at various points around the great circle of the sphere. Body, PL, and surface waves were observed. Density, layer thickness, compressional and shear-wave velocities were measured so that accurate surface-wave dispersion curves could be computed. Surface-wave dispersion was measured as well as computed. Measured PL mode dispersion compared favorably with theoretical computations. In addition, dispersion curves for Rayleigh, Stoneley, and Love modes were computed. Measured surface-wave dispersion showed Rayleigh and Love modes were observed but not Stoneley modes. Measured dispersion compared favorably with theoretical computations. The curvature correction applied to dispersion calculations in a flat space has been estimated to correct dispersion values at long-wave lengths to about one per cent of correct dispersion in a spherical model. Measured dispersion compared with such flat space dispersion corrected for curvature proved accurate within one per cent at long wave lengths. Two sets of surface waves were observed. One set was associated with body waves radiating outward from impact. The other set was associated with body waves reflecting at the pole opposite impact. For each set of surface waves, measured dispersion compared favorably with computed dispersion.

An Improved Transfer Matrix-Direct Integration Method for Rotor Dynamics

1986 ◽  
Vol 108 (2) ◽  
pp. 182-188 ◽  
Author(s):  
Jialiu Gu
Keyword(s):  
Transfer Matrix ◽  
Integration Method ◽  
Equations Of Motion ◽  
Rotor Dynamics ◽  
Direct Integration ◽  
Rotating System ◽  
Direct Integration Method ◽  
Mass Moment ◽  
Mass Moment Of Inertia ◽  
Matrix Iteration

A transfer matrix-direct integration combined method is proposed, which employs the transfer matrix method to derive the equations of motion of a “characteristic disk,” and uses the direct integration method to determine the critical speeds, modes and unbalance response of a rotor-bearing system, and to analyze its stability. Despite the complexity of the system, the number of governing equations is not greater than eight. For a single-spool rotating system, the number of equations is only four. A transfer matrix for a uniform shaft is derived to consider its distributed mass, moment of inertia and the effect of shearing force. An impedance matrix iteration method is proposed to consider the effect of a complicated bearing-supporting system on the rotor dynamics. Two examples are given, and the results agree satisfactorily with the experiments.

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