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GENERALIZED RAY APPROXIMATE METHOD TO INVERSE MEDIUM PARAMETERS
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作者 Niu, YQ Du, DS +1 位作者 Ma, XG Huang, WH 《Acta Mechanica Solida Sinica》 SCIE EI 1996年第1期59-65,共7页
In this paper, the inverse problem of the medium parameters in an inhomogeneous medium is studied and a generalized ray approximate form of the total wave field is described. First, the acoustic wave equation derived ... In this paper, the inverse problem of the medium parameters in an inhomogeneous medium is studied and a generalized ray approximate form of the total wave field is described. First, the acoustic wave equation derived from the elastic wave equation is studied, the referential variables and perturbational variables are introduced, and the integral equation of the medium perturbational parameters is obtained. Then from the point of view of the local principles of the wave function in an inhomogeneous medium, a generalized ray approximate form of the total wave field in an inhomogeneous medium is described, and attention is focused on the Fredholm integral equation of the first kind. Finally, the medium parameters in half-plane are inversed. Numerical examples show when the perturbations of the medium parameters are about 0.5, this method can effectively inverse its variation. Apparently, this method is better than the conventional Born weak scattering approximation. 展开更多
关键词 integral equation generalized ray approximation medium parameters function integral transform
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Transient impact responses of laminated composite cylindrical shells 被引量:1
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作者 Chunchuan Liu,Fengming Li,~(a)) and Wenhu Huang School of Astronautics,Harbin Institute of Technology,Harbin 150001,China 《Theoretical & Applied Mechanics Letters》 CAS 2011年第3期23-26,共4页
The generalized ray method(GRM) has been successfully used to study the transient elastic wave transmitting in the beams,planar trusses,space frames and infinite layered media.In this letter,the GRM is extended to inv... The generalized ray method(GRM) has been successfully used to study the transient elastic wave transmitting in the beams,planar trusses,space frames and infinite layered media.In this letter,the GRM is extended to investigate the early short time transient responses of laminated composite cylindrical shells under impact load.By using the Laplace transformation and referring to the boundary conditions,the ray groups transmitting in the finite laminated cylindrical shells under the shock load are obtained and the transient response related to each ray group can be derived via FFT algorithm.From the numerical results,it is shown that the early short time transient accelerations of the laminated composite cylindrical shell under impact loads are very large.But the short time transient shear strain and displacement are very small. 展开更多
关键词 laminated composite cylindrical shells impact load early short time transient response generalized ray method
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ANALYSIS AND EXPERIMENT ON TRANSIENT DYNAMIC RESPONSE IN FINITE MINDLIN PLATE 被引量:2
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作者 Fengming Li Chunchuan Liu Tingwei Liang 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2013年第2期129-139,共11页
The transient wave propagation in the finite rectangular Mindlin plate is investi- gated by the analytical and experimental methods. The generalized ray method (GRM) which has been successfully applied to study the ... The transient wave propagation in the finite rectangular Mindlin plate is investi- gated by the analytical and experimental methods. The generalized ray method (GRM) which has been successfully applied to study the transient responses of beams, planar trusses, space frames and infinite layered media is extended to investigate the transient wave propagation and early short time transient response in finite Mindlin plate. Combining the wave solution, the shock source and the boundary conditions, the ray groups transmitted in the finite rectangular plate can be determined. Numerical simulations and experiments are performed and compared with each other. The results show that the transient wave propagation and early short time transient responses in the finite plate can be studied using the GRM. The early short time transient acceler- ations are very large for the finite plate subjected to the unit impulse, while the early short time transient displacements are very small. The early short time transient accelerations under the unit impulse are much larger than those under the unit step impulse. The thickness and material characteristics have remarkable effects on the early short time transient responses. 展开更多
关键词 finite Mindlin plate transient wave propagation early short time transient response generalized ray method
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