Controlled Space Radiation concept for mesh-free semi-analytical technique to model wave fields in complex geometries.

Numerical modelling of the ultrasonic wave propagation is important for Structural Heath Monitoring and System Prognosis problems. In order to develop intelligent and adaptive structures with embedded damage detector and classifier mechanisms, detailed understanding of scattered wave fields due to anomaly in the structure is inevitably required. A detailed understanding of the problem demands a good modelling of the wave propagation in the problem geometry in virtual form. Therefore, efficient analytical, semi-analytical or numerical modelling techniques are required. In recent years a semi-analytical mesh-free technique called Distributed Point Source Method (DPSM) is being used for modelling various ultrasonic, electrostatic and electromagnetic wave field problems. In the conventional DPSM approach point sources are placed along the transducer faces, problem boundaries and interfaces to model incident and scattered fields. Every point source emits energy in all directions uniformly. Source strengths of these 360 degrees radiation sources are obtained by satisfying interface and boundary conditions of the problem. In conventional DPSM modelling approach it is assumed that the shadow zone does not require any special consideration. 360 degrees Radiation point sources should be capable of properly modelling shadow zones because all boundary and interface conditions are satisfied. In this paper it is investigated how good this assumption is by introducing the 'shadow zone' concept at the point source level and comparing the results generated by the conventional DPSM and by this modified approach where the conventional 360 degrees radiation point sources are replaced by the Controlled Space Radiation (CSR) sources.

[1]  Tribikram Kundu,et al.  Elastic wave propagation in sinusoidally corrugated waveguides. , 2006, Journal of the Acoustical Society of America.

[2]  Tribikram Kundu,et al.  Ultrasonic field modeling in plates immersed in fluid , 2007 .

[3]  Larry R. Myer,et al.  Numerical simulation of elastic wave propagation in fractured rock with the boundary integral equation method , 1996 .

[4]  Elfgard Kühnicke,et al.  Three‐dimensional waves in layered media with nonparallel and curved interfaces: A theoretical approach , 1996 .

[5]  Richard Paul Shaw.  Boundary integral equation methods applied to wave problems , 1979 .

[6]  Tribikram Kundu,et al.  Advanced Applications of Distributed Point Source Method – Ultrasonic Field Modeling in Solid Media , 2006 .

[7]  Ted Belytschko,et al.  A unified stability analysis of meshless particle methods , 2000 .

[8]  M. A. Breazeale,et al.  A diffraction beam field expressed as the superposition of Gaussian beams , 1988 .

[9]  Matthias G. Imhof,et al.  Computing the elastic scattering from inclusions using the multiple multipoles method in three dimensions , 2004 .

[10]  Martin Spies,et al.  Transducer field modeling in anisotropic media by superposition of Gaussian base functions , 1999 .

[11]  J. Raamachandran,et al.  Bending of anisotropic plates by charge simulation method , 1999 .

[12]  Francisco J. Sánchez-Sesma,et al.  DIFFRACTION OF P, SV AND RAYLEIGH WAVES BY TOPOGRAPHIC FEATURES: A BOUNDARY INTEGRAL FORMULATION , 1991 .

[13]  Ch. Hafner.  MMP calculations of guided waves , 1985 .

[14]  Tribikram Kundu,et al.  Semi-analytical modeling of ultrasonic fields in solids with internal anomalies immersed in a fluid , 2008 .

[15]  Tribikram Kundu,et al.  Elastic wave field computation in multilayered nonplanar solid structures: a mesh-free semianalytical approach. , 2008, The Journal of the Acoustical Society of America.

[16]  Dominique Placko,et al.  Ultrasonic Field Modeling in Multilayered Fluid Structures Using the Distributed Point Source Method Technique , 2006 .

[17]  John A. Hudson,et al.  Numerical modelling of seismic waves scattered by hydrofractures: application of the indirect boundary element method , 1998 .

[18]  P. K. Banerjee,et al.  Developments in boundary element methods , 1979 .

[19]  F. Sánchez-Sesma,et al.  Topographic effects for incident P, SV and Rayleigh waves , 1993 .

[20]  M. Bouchon,et al.  Boundary Integral Equations and Boundary Elements Methods in Elastodynamics , 2007 .

[21]  Ted Belytschko,et al.  ON THE COMPLETENESS OF MESHFREE PARTICLE METHODS , 1998 .

[22]  Cac Minh Dao,et al.  DPSM Modeling for Studying Interaction Between Bounded Ultrasonic Beams and Corrugated Plates with Experimental Verification , 2007, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.