Expert Details

Expert in Applied Mathematics & Techniques, Solid/Fluid Mechanics, Acoustics, Seismology, Fracture Mechanics

Expert ID: 724388 India

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He has wide research experience spanning over four decades in various fields of Applied Mathematics. Most of the work are published in very reputed journals like the Royal Society, London, Cambridge Philosophical Society, Royal Astronomical Society J. Applied Mechanics, (USA), Bulletin of the Seismological Society, (USA), Mechanics of Materials, J. Materials Science etc. His works are reviewed in Mathematical Reviews and Applied Mechanics Reviews internationally. Also some of his work have been cited in some NASA Reports. The key contributions are as follows:

Boundary –value problems pertaining to the Elastic Waves generated by tractions over a cavity/hole below the earth’s surface. This is a twin boundary case which defied solution for many years all over the world. He obtained the complete solution rigorously and analysed the results extensively. This is an important area for Seismology as well as Applied Mechanics. He has used special functions of Mathematics such as Bessel and Hankel functions, Integration, Multiple series Expansions, Cylindrical and Spherical coordinates, Wave equations, Convergence of series, Asymptotic approximations etc.

He has studied the problems of Dynamic tensile fractures of Plates and Shells due to Impulsive Loading on a surface region. For the first time this decades-old problem was tackled successfully using very original classification of the primary and secondary wave-fronts both compressive and tensile types.

Thus the locus of the fracture was predicted leading to the estimates of scab
Parameters. This work has inspired a NASA report in the USA. It has applications in the areas of structural safety and design. This expert had also been nominated as a member of the European Committee for Safety of Structures.

He has done outstanding work on the Surface wave diffraction across
Continental margins and mountain roots as part of the Cambridge University research assignment to explain theoretically the observed phenomena in many Academic Centres world-wide. This work had earlier been attempted at least for over 15 years in every known part of the academic world but with no direction!! This expert had solved this complex problem by using unimaginable intuition (!!) made possible only by an intense knowledge of the nature of the waves involved. Used mathematical tools comprising the Green’s function Representation Theorem, Iterative solutions, Shadow regions for certain waves, example of wedge-like shape leading to multiple transition regions for evaluating the transmission and reflection of waves. This is a land-mark work by the work.

He has worked on several problems on the Stress-concentration studies in elastic bodies that contain cracks, inclusions likde rigid ribbons etc. which frequently occur in Composite materials. Used techniques of Matched-asymptotic expansions, Chebyshev polynomial expansions and other analytical methods. Several papers have been published in the International J. Engineering Science.

He has another land-mark contribution in the new area pertaining to the Debonding of Inclusions in Composite materials. He has generalised the powerful technique of Eshelby’s equivalent Inclusion Method to 2-D and 3-D debonding models with elaborate numerical work on the stress-concentration. Several papers have been published in the J. Applied Mechanics, Mechanics of Materials etc. The expert has wide knowledge on the theoretical front.

He has made several applications of the Gaussian distributions for the study of the aerosol scatter and spread in the atmosphere taking into account the effects of atmospheric temperature and pressure, wind characteristics etc. This has been found in consonance with real-time effects observed.

Advised on the acoustic wave propagation in shallow waters.Scabbing of Plates and Shells due to explosives. Debonding of inclusions in Composites.Shock wave diffraction from inclined surfaces.

Education

Year Degree Subject Institution
Year: 1966 Degree: PhD Subject: Seismic Waves Institution: University of Delhi

Work History

Years Employer Title Department Responsibilities
Years: 1961 to 2000 Employer: Retired from Government Labs. Title: Director Department: Defence R&D Organisation, Delhi, India Responsibilities: Projects of Seismic, Acoustic and Electromagnetic wave applications Supervision & Guidance of Research, software development etc.
Years: 1983 to 1984 Employer: University of Newcastle, Australia Title: Senior Research Associate Department: Civil Engineering Responsibilities: Research in the Debonding of Composite materials.
Years: 1978 to 1980 Employer: Northwestern University, Evanston, Illinois, USA. Title: Research Associate. Department: Civil Engineering at Technological Institute. Responsibilities: Research in Stress concentration studies due to cracks and mapping of cracks etc.
Years: 1970 to 1972 Employer: Cambridge University, England Title: Research Fellow Department: Applied Maths. and Theoretical Physics Responsibilities: Theoretical research on Rayleigh wave propagation across wedge-like surfaces for seismic applications.

Government Experience

Years Agency Role Description
Years: 1961 to 2000 Agency: Role: Description:

International Experience

Years Country / Region Summary
Years: 1970 to 1972 Country / Region: UK, Cambridge University Summary: Carried out Surface wave diffraction in Seismology.
Years: 1978 to 1980 Country / Region: USA, Northwestern University Summary: Contributed to Crack mapping by far-field scattering data.
Years: 1983 to 1984 Country / Region: Australia, University of Newcastle. Summary: Contributed Original solution to debonding in composites by a generalisation of the famous Eshelby's equivalent inclusion method.

Career Accomplishments

Associations / Societies
Life Member Acoustical Society of India. Invited Speaker at ISTAM, IUGG conferences in USA.
Publications and Patents Summary
Published over 50 research papers including in the Royal Society, London, Transactions of the ASME etc. Guided PhD students.

Additional Experience

Training / Seminars
Trained scientists in the areas of Numerical Analysis, Fortran based scientific software etc.
Other Relevant Experience
Can guide work on Seismic, Acoustic and Electromagnetic wave propagation and scattering. Crack generated stress concentration studies, General modeling of Composite materials etc, . Can advise on numerical techniques Differential equations etc.

Language Skills

Language Proficiency
English All education in English medium.

Fields of Expertise

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