DEFORMATION AND FAILURE OF COMPOSITE STRUCTURES

THE MORK FAMILY DEPARTMENT OF CHEMICAL ENGINEERING AND MATERIALS SCIENCEPRESENTS A JOINT SEMINAR
BYChiara Bisagni
Ph.D., Fulbright FellowDepartment of Mechnical Engineering
Massachusetts Institute of TechnologyDEFORMATION AND FAILURE OF COMPOSITE STRUCTURESABSTRACTAfter a brief presentation of the research activities and experimental facilities of the Department of Aerospace Engineering of Politecnico di Milano, Italy, the lecture will focus on the experimental and numerical investigations carried out by Chiara Bisagni during the last years concerning mainly 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. 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. Also, the first results of the research now under way will be presented. It considers cyclic buckling tests on composite boxes with combined loads, and the detection of damage propagation during the tests on stiffened buckling structures.The second part of the presentation will consider energy absorption requirements. Indeed, 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 componentsFebruary 23, 2007
2:45-3:45 PM
(Refreshments will be served at 2:30 PM)
SLH 102**ALL FIRST YEAR MATERIALS SCIENCE MAJORS ARE REQUIRED TO ATTEND**

Location: John Stauffer Science Lecture Hall (SLH) - 102

Audiences: Everyone Is Invited

Contact: Petra Pearce