Events for February 23, 2007
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Stochastic Uncertainty Quantification Approaches for Large Scale Subsurface Problems
Fri, Feb 23, 2007 @ 11:15 AM
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
Graduate SeminarStochastic Uncertainty Quantification
Approaches for Large Scale Subsurface
ProblemsProfessor Dongxiao Zhang
Petroleum and Geological Engineering
The University of OklahomaAbstract
Prediction of subsurface flow and transport is subject to uncertainties, which can
result from the heterogeneity of the media and our incomplete knowledge about
their properties. Such uncertainties render the model parameters random and the
equations describing flow and transport in the media stochastic. Monte Carlo
simulation method (MCS) is the most common and conceptually straightforward
approach. However, it requires large computational efforts, especially for large scale
problems. Recently, a number of alternative stochastic approaches have been
developed to quantifying prediction uncertainties. This talk discusses four
representative methods: The moment equation method (ME); the Galerkin
polynomial chaos expansion method (PCE); the Karhunen-Loeve based moment
equation method (KLME); and the probabilistic collocation method (PCM). The
efficiency of these methods depends on how the random (probability) space is
approximated. Detailed theoretical analyses and numerical computations are
performed to compare these methods against MCS in terms of accuracy, efficiency,
validity range, and compatibility with existing deterministic simulators. It is found that
the KLME, PCE and PCM are generally more efficient than the MCS and the ME for
larger-scale problems. The expansions in representing the dependent random fields
and the ways for evaluating the expansion coefficients distinguish among the KLME,
PCE and PCM.Friday, February 23, 2007
Seminar at 11:15 a.m.
HED 116The Scientific Community is cordially invited.Location: Hedco Pertroleum and Chemical Engineering Building (HED) - 116
Audiences: Everyone Is Invited
Contact: Petra Pearce
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DEFORMATION AND FAILURE OF COMPOSITE STRUCTURES
Fri, Feb 23, 2007 @ 02:45 PM
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
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