December 4, 2006 Volume 3, Number 17
Upcoming Lecture:
Composite structures under buckling and energy absorption requirements
On Monday, December 11 from 10:30 a.m.-noon, Chiara, Bisagni, Ph.D., Visiting Associate Professor for MIT and Associate Professor of the Politecnicio di Milano will present a lecture: Composite structures under buckling and energy absorption requirements. The lecture will be held in NIAR room 307-309 on the Wichita State campus and is free and open to the public.
 | Chiara Bisagni, Ph.D., Fulbright Fellow
Visiting Associate Professor, MIT Massachusetts Institute of Technology
Professore Associato, Politecnico di Milano
Dipartimento di Ingegneria Aerospaziale
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Dr. Bisagni will give a brief presentation of the research activities and experimental facilities of the Department of Aerospace Engineering of Politecnico di Milano, Italy, then will focus on her own experimental and numerical investigations during the last years concerning composite structures under buckling and energy absorption requirements.
The first part of the presentation will consider the structural behavior of composite structures under buckling requirements. Fiber reinforced composites are an important class of engineering materials due to their high specific mechanical properties. Unlike isotropic materials, they have a complex response to loading and offer a not well-known behavior in the post-buckling field. The main reason is that the presence of several laminae, with different lay-up and properties, makes composite material performances in a non-linear field very difficult to predict. This leads to the necessity to conduct an intensive investigation and experimental tests in different load conditions. Some results on stringer stiffened composite panels subjected to buckling under compression and shear will be presented. In particular, the investigation of fuselage panels and of a helicopter tailplane performed during two European projects (POSICOSS, "Improved post-buckling simulation for design of fibre composite stiffened structures", and COCOMAT, "Improved Material Exploitation at Safe Design of Composite Airframe Structures by Accurate Simulation of Collapse") will be presented.
The second part of the presentation will consider energy absorption requirements. Crashworthiness related to composite materials has now become a serious issue, as composite structures have the possibilities to absorb an even superior amount of energy compared to metals, with contained costs. But the crash analysis of composite structures remains particularly challenging due to the complexity and diversity of failure modes that composites exhibit under crushing loads. The experimental and numerical investigation on the energy absorbing capabilities of intersection elements for helicopter subfloor, and of Formula One car components will be presented. In particular, a building block approach has been used to calibrate the numerical model, analyzing at first coupon testing and tube crushing experiments, and then crash tests of the helicopter and Formula One car components.
For more information about Dr. Bisagni, visit her homepage.
The lecture is sponsored by the Wichita State University College of Engineering and the National Institute for Aviation Research.
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