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Full-scale simulation of multiple scattering of elastic waves in fiber reinforced composites

IP.com Disclosure Number: IPCOM000128026D
Original Publication Date: 1998-Dec-31
Included in the Prior Art Database: 2005-Sep-14
Document File: 6 page(s) / 21K

Publishing Venue

Software Patent Institute

Related People

Cai, Liang-Wu: AUTHOR [+3]

Related Documents

http://theses.mit.edu:80/Dienst/UI/2.0/Describe/0018.mit.theses/1998-212: URL

Abstract

Multiple scattering phenomena are of enormous interest in many disciplines, especially nondestructive evaluation of materials. Starting from a single fiber scattering model, a computational system is built for conducting full-scale deterministic simulations of multiple scattering of elastic waves in fiber reinforced composites. The computational system is based on two theoretical developments, The first is the formulation of two-dimensional multiple scattering problems involving arbitrary numbers of scatterers. The resulting solutions are analytically exact, for scatterers that may be similar or dissimilar, The second theoretical development, which we name scatterer polymerization, enables assemblages of arbitrary numbers of scatterers to be modeled as single scatterers in sequential analyses, while maintaining analytically exact solutions. Both the multiple scattering solutions and the scatterer polymerization methodology can be used as independent tools to analyze multiple scattering problems, Each has been implemented and verified. By combining these tools, analytically exact solutions have been obtained for multiple scattering phenomena in models of composites containing thousands of fibers, The feasibility and the procedures for such full-scale simulations are demonstrated. Finally, as a comprehensive example, a ceramic-fiber reinforced metal-matrix composite plate is modeled, and the effects on the scattered waves due to changing microstructural parameters of the composite are examined, Thesis Committee;

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Page 1 of 6

 This record is the front matter from a document that appears on a server at MIT and is used through permission from MIT. See http://theses.mit.edu:80/Dienst/UI/2.0/Describe/0018.mit.theses/1998-212 for copyright details and for the full document in image form.

FULL-SCALE SIMULATION OF MULTIPLE SCATTERING OF ELASTIC WAVES IN FIBER REINFORCED COMPOSITES

by

Liang-Wu Car


B.S, Applied Mechanics The University of Science and Technology of China (1985)

M,E., Solid Mechanics The Chinese Academy of Sciences (1988) Submitted in partial fulfillment of the requirements for the degree of DOCTOR OF SCIENCE in MECHANICAL ENGINEERING

at the Massachusetts Institute of Technology June 1998
SIGNATURE OF author: [[signature omitted]]

Department of Mechanical Engineering

May 11, 1998
CERTIFIED BY: [[SIGNATURE OMITTED]]

James H. Williams, Jr.

SEPTE Professor of Engineering Thesis Supervisor ACCEPTED BY: [[SIGNATURE OMITTED]]

Anthony T, Patera Acting Chairman Departmental Committee on Graduate Studies ARCHIVES MASSACHUSETTS INSTITUTE OF TECHNOLOGY LIBRARIES AUG 04 1998

Massachusetts Institute of Technology Page 1 Dec 31, 1998

Page 2 of 6

Full-scale simulation of multiple scattering of elastic waves in fiber reinforced composites

FULL-SCALE SIMULATION OF MULTIPLE SCATTERING OF ELASTIC WAVES IN FIBER REINFORCED COMPOSITES

by

Liang-Wu Cai

Submitted to the Department of Mechanical Engineering on May 11, 1998 in partial fulfillment of the requirements for the degree of Doctor of Science in Mechanical Engineering

ABSTRACT

Multiple scattering phenomena are of enormous interest in many disciplines, especially nondestructive evaluation of materials. Starting from a single fiber scattering model, a computational system is built for conducting full-scale deterministic simulations of multiple scattering of elastic waves in fiber reinforced composites.

The computational system is based on two theoretical developments, The first is the formulation of two-dimensional multiple scattering problems involving arbitrary numbers of scatterers. The resulting solutions are analytically exact, for scatterers that may be similar or dissimilar, The second theoretical development, which we name scatterer polymerization, enables assemblages of arbitrary numbers of scatterers to be modeled as single scatterers in sequential analyses, while maintaining analytically exact solutions.

Both the multiple scattering solutions and the scatterer polymerization methodology can be used as independent tools to analyze multiple scattering problems, Each has been implemented and verified. By combining these tools, analytically exact solutions have been obtained for multiple scattering phenomena in models of composites containing thousands of fibers, The feasibility and the procedures for such full-scale simulations are demonstrated.

Finally, as a comprehensive example, a ceramic-fiber reinforced metal-matrix composite plate is modeled, and the effects on the scattered waves due to changing micro...