Plenary Lecture

Improvement of Sandwich Finite Elements by Mixed Formulations

Professor Olga Martin
Applied Sciences Faculty
University “Politehnica” of Bucharest
Splaiul Independentei 313
Bucharest, ROMANIA
E-mail: omartin_ro@yahoo.ro

Abstract: Honeycomb sandwich structures are used extensively on both civil and military aircraft due to their high stiffness and low weight. The designers employ honeycomb sandwich structures on numerous parts of the aircraft including control surfaces, floor panels, access panels and doors, at rear of plane to improve the sonic fatigue resistance and replace the thin plate skin by a honeycomb “plank”.
A panel consists of thin stiff face-sheets, either of aluminum alloy or composite (glass/ epoxy, graphite/epoxy etc.), adhesively bonded to a thick honeycomb core that is typically manufactured from aluminum. The honeycomb core provides a lightweight yet stiff structure.
In the present study a model that reduces the honeycomb structure to one classical (with cells) keeping the stiffness is carried out. The theoretical results have been applied to the finding of the stresses and safety margins with a finite element program for an aileron structure that contains a wedge of honeycomb sandwich. This study also gives the procedures for determining core thickness and core shear modulus so that the overall buckling of sandwich panel will not occur.

Brief Biography of the Speaker:
Olga Martin graduated the Faculty of Mathematics and Mechanics, University of Bucharest, Romania. She received his PhD in mathematics with the specialization in Dynamic Plasticity with paperwork ‘Applications of the Finite Element Method in Dynamic Plasticity’. During of twenty years, she had been senior researcher in Aircraft Institute, Strength Materials Department. Technical experience: structural strength computing reports using ANSYS program (wing-fuselage, fuselage frame, fin, elevator, rudder and aileron), dynamic and static test-programs for aircraft structures, fatigue test-programs for aircraft structures, iterative methods for the study of the reactions, which correspond to movable control surfaces, attached at n – points to an elastic structure and program of this, static and fatigue computation of the propeller (mono-bloc hub, blades and blades retention system).
Nowadays, she is Professor, Applied Sciences Faculty, University Politehnica of Bucharest.
Fields of specialization: Mathematical Analysis, Mathematical Physics, Computational and Experimental Solid Mechanics, Numerical Analysis, Statistical Calculus.
She has published over 80 research papers and 18 books.
She is member of the editorial boards of Politehnica Sci. Bull. Series A, WSEAS Transactions on Applied and Theoretical Mechanics, WSEAS Transactions on Mathematics and she was involved in the program/organizing committees for many international conferences.
Membership of Professional Societies
Society of Computer Aided Engineering – Member
National Union of Romanian Scientists (Founding member)
Balkan Society of Geometers, member
Reviewer: WSEAS Press (books and journals), Scientific Bulletin, Politehnica University of Bucharest
Scientific Evaluation Societies: RELANSIN, Politehnica University of Bucharest, ARACIS, Bucharest, CNCSIS, Bucharest
National Science Fund of Bulgaria.