Plenary Lecture

A Numerical Approach for Determining Elastic Material Properties from Experimental Data

Professor Leonardo Pagnotta
Department of Mechanical Engineering
University of Calabria
Ponte P. Bucci 44C, Arcavacata di Rende (CS)
ITALY
E-mail: Pagnotta@unical.it

Abstract: The elastic properties of solids play a fundamental role in both scientific and technological fields. Their measurement provides information regarding the forces exchanged among the atoms or ions that compose a solid, so helping to characterize the nature of the links. It also allows us to describe the mechanical behaviour of the material which is fundamental for the structural design and experimental stress analysis. Moreover, the possibility of measuring the elastic constants of materials, fast and accurately, during the manufacturing cycle of a product could help with quality control. As a result there are many methodologies for the elastic characterization of materials. To day there is still great interest in this subject especially in the context of the development of the new and more complex materials for which the classic methods of characterization appear time-consuming, expensive and, in some cases, unsuitable.
The lecture deals with a promising recent methodology for the characterization of isotropic or anisotropic materials. The elastic constants are identified through a process that minimizes the difference between the dynamic or static response of the real structure (measured response) and the response of the same structure predicted from a numerical model (virtual response). This method updates iteratively the values of the elastic constants of material in the model, until the virtual response (the first natural frequencies in the dynamic approach or the field of the superficial displacements in static approach) approximates as closely as possible the real response measured by means of experimental observations. The values of the constants used in the last iteration are the elastic properties of the material. The identification of all the elastic constants can take place simultaneously, with a single experiment and without damaging the specimen.

Brief Biography of the Speaker:
Leonardo Pagnotta was born in Pizzo (Vibo Valentia, Italy), May 16, 1957. He graduated in Mechanical Engineering in 1984 at the University of Calabria (Arcavacata di Rende, Cosenza, Italy) and he received his PhD in Mechanics of Materials from the University of Pisa in 1990. He was appointed researcher in Experimental Mechanics in 1994, associate professor of Machine Design in Mechanical Engineering in 2000 and full professor in 2006. At present he is professor at the Faculty of Engineering of University of Calabria for which he has held courses in Machine Design, Mechanics of Materials, Mechanics of Composite Materials, Theory of measurement, Instrumentation for mechanical and thermal measurements since 1990. From 2004, he is also holding a course of Biomedical Instrumentation at University “Magna Grecia” of Catanzaro.
His research activities have been addressed to numerical methodologies for stress analysis, reliability design of ceramic material component, structural optimization of composite material component, and methods of experimental mechanics (strain gages, holographic and speckle interferometry and integrated photoelasticity) applied to residual stress measurement in metals and optical fiber, elastic properties measurement of isotropic and anisotropic material, fracture mechanics, and non-destructive testing. Recently, he is developing numerical-experimental methodologies for the elastic characterization of anisotropic materials by vibrational and static techniques. Professor Pagnotta has published about 80 scientific research papers.