Papers by Keyword: SH Wave

Paper TitlePage

Authors: Jie Yang, Dong Li
Abstract: The analytical solution to a cylindrical inclusion with an eccentric crack impacted incident SH waves was studied by using the methods of Green function and conjunction. Firstly, Green function was constructed, which was an essentical solution of displacement field for an elastic half space containing a half cylindrical inclusion while bearing out-of-plane harmonic line source force at any point of its horizontal boundary. Secondly, the whole space was divided into two parts via conjunction technology, a series of unknown forces were loaded at the linking sections to satisfy continuity conditions.Thirdly, the Fredholm integral equations of the first kind were set up through the continuity conditions and the Green function. Finally, a example for dynamic stress intensity factor for mode III at the crack tip was given. Numerical results show that the dynamic stress intensity factors is influenced by wave numbers and media parameters.
970
Authors: Xin Gang Li, Cheng Jin, Li Zhang, Da Yong Chu
Abstract: In this paper, the behavior of a finite crack in an infinite plate of functionally graded materials (FGM) with free boundary subjected to SH-waves is considered. To make the analysis tractable, it is assumed that the material properties vary exponentially with the thickness direction and the problem is transformed into a dual integrated equation with the method of integral transform. The dynamic stress intensity factor is obtained using Schmidt method. The numerical examples are presented to demonstrate this numerical technique for SH-waves propagating in FGM plate. Finally the number of the waves, the gradient parameter of FGM and the angle of the incidence upon the dynamic stress intensity factor are also given.
38
Authors: Hui Wen Wang, Zai Lin Yang, Hua Nan Xu
Abstract: The problem of dynamic response of multiple circular cavities near multiple semi-cylindrical alluvial valleys under incident plane SH-waves is investigated by the methods of complex function and multi-polar coordinates in this paper. Firstly, the solution domain is divided into two parts, Domain I is multiple semi-cylindrical alluvial valleys, and Domain Ⅱ is an elastic half space with several subsurface circular cavities near multiple semi-cylindrical alluvial valleys. A series of infinite algebraic equations is then obtained based on the displacement and stress continuity condition on “common boundary” of two parts after constructing the associated displacement and stresses expressions of each part. Finally some numerical expamples are prensented and dynamic response of subsurface circular cavities near semi-cylindrical alluvial valleys with respect to different parameters is discussed.
3253
Authors: Hui Qi, Li Ming Cai, Xiang Nan Pan, Chun Gao
Abstract: Steady state responses of a circular cavity and a semi-circular canyon subjected by plane SH wave in an elastic quarter are presented by using Fourier-Hankel wave function expansion method and image method with Fourier series expansion on the boundary conditions to determine linear algebraic equations of unknown wave function coefficients. Especially, displacement and stress component expressions are formulated for incident, reflected, scattering waves, respectively. This method can provide an analytical ideas and methods for further studies of elastodynamic interface problems.
1581
Authors: Zhi Ying Ou, Xiao Wei Liu, Qiong Deng
Abstract: When the radius of materials and structral devices reduces to nanometers, the influence of surface energy becomes prominent in its mechanical behavior. In the frame of surface elasticity, the scattering of anti-plan shear waves by an elastic half-plan with a semi-cylindrical cavity considered the surface energy are investigated in this paper. When the boundary condition at the straight edge of the half-plan is traction free, the analytical solutions of stress fields of the half plan with semi-culindrical cavity are expressed by employing a wave function expansion method. The results show that surface energy has a significant effect on the scattering of anti-plan shear waves as the radius of the semi-cylindrical cavity shrinks to nanoscale. The effects of incident waves with different frequencies and incident angel, radius of semi-cylindrical cavity and surface energy on the dynamic stress concentration around the semi-cylindrical cavity are discussed in detail.
698
Authors: Xin Gang Li, Zhen Qing Wang, Nian Chun Lü
Abstract: The dynamic stress field under the SH-waves at the moving crack tip of functionally graded materials is analyzed, and the influences of parameters such as graded parameter, crack velocity, the angle of the incidence and the number of the waves on dynamic stress intensity factor are also studied. Due to the same time factor of scattering wave and incident wave, the scattering model of the crack tip can be constructed by making use of the displacement function of harmonic load in the infinite plane. The dual integral equation of moving crack problem subjected to SH-waves is obtained through Fourier transform with the help of the exponent model of the shear modulus and density, then have some process on the even and odd term of the integral kernel. The displacement is expanded into series form using Jacobi Polynomial, and then the semi-analytic and numerical solutions of dynamic stress intensity factor are derived with Schmidt method.
683
Authors: Hui Qi, Gen Chang Zhang, Jing Fu Nan
Abstract: The seismic ground motions are studied in an infinite half-space with a non-circular alluvial valley under time harmonic incident anti-plane shear waves. Based on the conformal mapping method and Fourier series expansions, the conditions of displacement continuity and stress equilibrium at the interface of alluvial valley are set as semi-circular alluvial valley in conformal plane, then the result is obtained by constructing a set of infinite linear algebraic equations with boundary discretization. The unknown coefficients in the algebraic system can be easily determined. The present method is treated as a semi-analytical solution since error only attributes to the truncation of Fourier series. Earthquake analysis for the site response of alluvial valley or canyon subject to the incident SH-wave is the main concern. Numerical examples for semi-elliptic alluvial valley are given to test our program. The research indicates that great interaction exists between the alluvial valley and the horizontal surface, which will bring on great influence on ground motion. Therefore enough importance must be attached to the existing of subsurface cavity while finishing seismic design.
2092
Authors: Mi Ra Cho, Ki Bong Kim, Sung Ho Joh, Tae Ho Kang
Abstract: The impact-echo method, which is to evaluate the integrity of concrete and masonry structures nondestructively, is an excellent method in practical applications, and provides a high quality of structural integrity assessment. However, in the case of multi-layered systems in which each layer has different stiffness, the impact-echo method may lack reliability in thickness evaluation, which demands improvement of the impact-echo method. This study was first dedicated to the understanding of stress-wave propagation in the impact-echo test, and secondly, the reliability of the impact-echo method was investigated through the numerical simulation of the impact-echo test. The investigation included the research on influencing factors such as stiffness contrast between layers and receiver location. Finally, the research in this paper led to the development of the phase-difference response (PDR) method, based on the frequency response between two receivers deployed in a line with an impact source.
336
Authors: An Ling Wang, Fu Ping Liu
Abstract: Using the lateral shift and shift time of reflection coefficient of SH seismic wave at the interface of strata, , we derived and given formulae of normal moveout of lateral shift, discussed the influence of lateral shift on normal moveout of SH-wave, and drawn the curves of normal moveout of lateral shift and the error of normal moveout caused by lateral shift with respect to the angle of incidence. The results show that for glancing wave or angle of incidence being near the critical angle, A large error can be caused by t lateral shift; The error correction of lateral shift should be done before seismic data processing.
1530
Authors: An Ling Wang, Fu Ping Liu
Abstract: Using the lateral ,shift and shift time of REFRACTION coefficient of SH seismic wave at the interface of strata, we derived and given formulae of normal move out of lateral shift, discussed the influence of lateral shift on normal move out of SH-wave, and drawn the curves of normal move out of lateral shift and the error of normal move out caused by lateral shift with respect to the angle of incidence. The results show that for glancing wave or angle of incidence being near the critical angle, A large error can be caused by lateral shift; The error correction of lateral shift should be done before seismic data processing.
408
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