Plenary Lecture

A Rational Integrated Approach to Designer Materials, Aerodynamics, Structural Control and Vehicle Performance: Analytical and Computational Issues

Professor Harry H. Hilton
University of Illinois at Urbana-Champaign
Department of Aerospace Engineering
National Center for Supercomputing Applications
104 South Wright Street, Urbana, IL 61801-2935
United States of America

Abstract: Traditional protocols as well as past and current conventional wisdom dictate that structural members be analyzed and designed based on readily available “off the shelf” materials. Similarly, aerodynamic shapes are selected from catalogued airfoils and performance is placed on a “best can do” rational. Prescribed limitations, such as constraints on cost, weight, some dimensions, service performances, etc., then leave open only one or two dimensional adjustments for each structural member in order to attempt to satisfy the desired operational effects.
On the other hand, the Computational Structural/Solid Mechanics Group at NCSA/TRECC has developed a novel general analytical approach that is based on the calculus of variations, where material properties, morphed airfoil shapes and servo-controls are tailored/engineered to produce prescribed structural, aerodynamic, aeroelastic and aero-viscoelastic effects as well as flight performance. In essence, this replaces the present prevailing reliance on geometric sizing and supersedes it with optimal material and aerodynamic behavior for each structural element and aerodynamic shape.. Effectively, one does not set out to build a better mouse trap mechanism, but rather analytically
determine optimal properties, which if manufactured will produce the “best” mouse trap.
The fundamental paradigm for flight and submarine light-weight structures is the pervasive requirements for analyses and designs that yield high-strength yet lightweight material construction and high lift/low drag devices with integrated with fluid/solid interactions. To that end, proper materials, analytical and computational tools and novel cost effective approaches must be initiated and utilized. Composites have found wide acceptance in fulfilling a significant number of these requirements and are being used to replace many traditional metal (aluminum, magnesium, titanium, etc.) structural components. However, they generally do not behave elastically but rather viscoelastically thus bringing into focus the additional time dimension; relaxation and creep properties and degradation of moduli and failure stresses with time. Ultimately, viscoelasticity introduces new phenomena, such as damping, creep and time dependent failure concepts leading to structural lifetime or survival time criteria as well as deformation induced alterations in aerodynamic responses.
The ultimate benefits stemming from analyses based on designer materials, aerodynamics and controls are that more efficient overall optimal systems can be realized in terms of overall material properties, sizing, performance, response to loads and temperatures, etc.
Of course, the as yet unexamined additionally needed new procedures for manufacturing structural materials to prescribed specifications based on their a priory mechanical properties require to be addressed separately by material scientists. If nothing else, at least new data bases of needed material properties can be established through computer simulations of the analytical results which will serve as guides to materials manufacturers as to what properties are desirable and needed. A parallel statement can be made for new airfoil geometries.

Brief Biography of the Speaker:
BS 47 and MS 49 Aeronautical Eng. (compressible aerodynamics) New York U., Ph. D. Theoretical & Applied Mechanics (solid mechanics major with mathematics minor) 51 U of IL. At UIUC since 1949. Aeronautical & Astronautical Eng. department head 74 - 85, assistant dean of engineering sum-mers 1989 & 90. Charles E. Schmidt Distinguished Visiting Professor, Florida Atlantic U., 1997 – 2001, 2007. Fellow of the American Institute of Aeronautics and Astronautics (AIAA). External examiner Nanyang Technological University, Singapore.
Current member of the AIAA Structures Technical Committee, AIAA Advisory Committee on Web Development, AIAA Non-Deterministic Applications Technical Committee, ASME Random Structural Problems Committee, the ASTM Committee D-30 on Composite Materials and two scientific committees organizing international conferences. He is also chairs the AIAA Illinois Section and is a regional director for Sigma Gamma Tau, the national aerospace engineering honor society.
After his retirement in 1990, he has continued to be actively engaged in research, teaching, MS & PhD thesis advising and in public and professional service. He has published or had accepted for publication over 300 papers in archival journals or conference proceedings. His current active analytical & computational research areas are deterministic and stochastic linear and nonlinear viscoelasticity, composites, aeroviscoelasti city, aerodynamic noise, computational solid me¬chanics, structural control and probabilistic failure criteria and analysis, damping & nonlinear dynamics, linear & nonlinear anisotropic viscoelastic finite element analysis, optimum designer materials, piezoelectric, magnetic, and functionally graded viscoelastic materials, electronic packaging, nonlinear creep and delamination column & plate buckling, analytical determination of damping properties, material characterization, stochastic minimum structural weight analysis, probabilistic delamination of composites during service and manufacturing processes (cure), structural control and survivability, engineering education, and structural integrity of dentures.




WSEAS Unifying the Science