May 4, 2005 (Wednesday)
Inter-School Lab, 3:30-5:00 pm
Mindlin Lecture
Dr. Ken P. Chong
The National Science Foundation
Nano Science and Engineering in Mechanics
Dr. Chong is the grand-student of Prof. Mindlin. His advisor......click above link to read more
January 27, 2005 (Thursday, 825 Mudd) 2:30-3:30 p.m.
Can One Hear The Shape of a Drum? and Related Topics
Dr. Isaac Elishakoff
J.M. Rubin Distinguished Professor
Department of Mechanical Eng., Florida Atlantic University
Abstract: A mathematician , Marc Kac, was the first one to pose
the question in the title over a quarter century ago.The essence
of the question is whether the infinite set of eigenvalues of a simply
supported membrane determines the shape of the membrane uniquely.This
question generated numerous works and finally a negative reply. In this
lecture we deal with modest and more realistic objective:Construct a
structure whose fundamental mode shape is postulated,rather than its
spectrum.As often happens,this humbler approach showed that 'less is
more': some apparently first closed form solutions are derived since
the pioneering work of Leonhard Euler in vibration and buckling.
February 24, 2005 (Thursday, 825 Mudd) 2:30-3:30 p.m.
Interface
Between Solid Mechanics and Physics/Chemistry: Some Recent Studies on
the Mechanics Governing Novel Small Material Structures
Prof. Xi Chen
Assistant Professor, Department of Civil Engineering and Engineering Mechanics
Solid mechanics developed at the continuum scale is the
foundation of engineering and one of the oldest branch of physics. By
collaborating with several applied physics/material chemistry groups,
we have recently extended the scope of continuum mechanics to study the
deformation and failure mechanisms of novel small material structures,
including spontaneous buckling pattern formations in thin metal films,
self-assembled colloidosome capsules, and ion beam radiation induced
nano-sculpting. It is shown that solid mechanics can make substantial
contributions to material integrity and reliability at small-scale.
March 10, 2005 (Thursday, Davis Auditorium) 5:00-6:30 p.m.
The Dongju Lee Memorial Lecture
Liquefaction of Fine-Grained Soils and Its Effects on Buildings
Prof. Jonathan D. Bray, Department of Civil and Environmental Engineering, University of California, Berkeley
Abstract: Ground failure in Adapazari, Turkey
during the 1999 Kocaeli earthquake was severe.
Hundreds of structures settled, slid, tilted, and collapsed due in part
to liquefaction. The soils that led to
severe building damage were generally low plasticity silts. A comprehensive investigation was completed
to understand the effects of subsurface conditions on the occurrence of ground failure
and its resulting effects on building performance. The CPT was able to identify thin seams of
loose liquefiable silt, and the SPT (with retrieved samples) allowed for
reliable evaluation of the liquefaction susceptibility of fine-grained
soils. State-of-the-practice CPT- and
SPT-based liquefaction triggering procedures adequately identified soils that
liquefied only if the Chinese criteria were disregarded. Field observations and cyclic tests show that the Chinese criteria
are not reliable for determining the liquefaction susceptibility of
fine-grained soils. Soils that liquefied
did not typically meet the clay-size criterion of the Chinese criteria. It is not the amount of “clay-size” particles
in the soil; rather it is the amount and type of clay minerals that best
indicate a soil’s susceptibility to liquefaction. The soil’s plasticity index is thus a better
indicator. A new liquefaction susceptibility criterion for fine-grained soils
is proposed based on the results of this field and laboratory testing program.
March 17, 2005 (Thursday)
Prof. Qiang Yu (host-Prof. Xi Chen, Joint Seminar with Dept of Mechanical Engineering)
Recent Advances in Design Methodologies
Department of Mechanical Engineering, Yokohama National University, Japan
Abstract At Yokohama National University, our research fields are
Material Mechanics and Computational Mechanics, and our research topics
are about multidisciplinary optimization design methods using Response
Surface Approach and reliability assessment and design of
micro-structure. Our laboratory has developed several new methods for
the problem of collaborative optimization, such as mode-control
approach, robust design approach and multi-level approach. These
approaches have been satisfactorily applied to the optimization
problems of vehicle collision designs.
Prof. T.P. Tassios
National Technical University of Athens
Tuesday, March 29, at 6:30 p.m.
Moral-Political Issues in Sustainable Development
Wednesday, March 30, at 6:30 p.m.
BUILD-OPERATE and TRANSFER Public Works in Ancient Greece
Place: Davis Auditorium
April 21, 2005 (Thursday)
825 Mudd (2:30-3:30 p.m.)
Prof. Rob Y. Chai
Department of Civil and Environmental Engineering
University of California, Davis
Seismic Response of Extended Pile-Shafts for Bridge
Structures
Current design of extended pile-shafts for bridge structures assumes an
inelastic response under the design level earthquake. Even though full
detailing requirements are imposed on these structures, they are designed to a
lower level of ductility demand compared to fixed-base columns. The lateral
stiffness, strength and ductility capacity of these structures depend on the
above-ground height, axial force, amount and details of the longitudinal and
transverse reinforcement, and the interaction between the pile and surrounding
soil. This seminar will present the results of an experimental project
investigating the inelastic response of extended pile-shafts. Test results
indicated that the ultimate lateral strength is not sensitive to the density of
the soil. Measured curvature distributions along the length of the pile also
indicated that the equivalent plastic hinge length is longer than that of
fixed-base reinforced concrete columns, and depends primarily on the
above-ground height, and not sensitive to the soil density. A simple model,
based on the equivalent cantilever concept and suitable for preliminary design,
will be discussed and illustrated with examples. The implication of P-D effects on the lateral response of piles, particularly for
tall piles embedded in soft soils, will also be discussed.