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Ying Li's picture

爆炸力学的发展史

爆炸力学是力学的一个分支,它主要研究爆炸的发生和发展规律,以及爆炸的力学效应的利用和防护的学科。它从力学角度研究化学爆炸、核爆炸、电爆炸、粒子束爆炸(也称辐射爆炸)、高速碰撞等能量突然释放或急剧转化的过程,以及由此产生的强冲击波(又称激波)、高速流动、大变形和破坏、抛掷等效应。自然界的雷电、地震、火山爆发、陨石碰撞、星体爆发等现象也可用爆炸力学方法来研究。

Mogadalai Gururajan's picture

Computer simulations and visualization: Seed video

Here is a video from the Seed magazine called Science in Silico. The video shows results from large scale simulations (and visualization) of fractals, microscopic dynamic processes in ribosomes, structure of viruses, bacterial flagellum, turbulence, explosions, and the modelling of cosmological events.

Teng Li's picture

iMechanica now has 2000+ registered users

iMechanica was lunched on 9 September 2006. It took about five months for iMechanica to see its 1000th registered user. Today we are welcoming the 2000th registered user after only another two and half months.

MichelleLOyen's picture

New Micromechanics Book

This message about a new book came over the PoroNet (poroelasticity network) mailing list:

Dear Colleagues:

      I would like to inform you that my book "Micromechanics of Heterogeneous Materials” (containing around 700 pages, 140 figures, 3000 formulae, and 1200 references) should be published by Springer on 07.06.07. [Details are on the web http://www.springer.com/west/home/engineering?SGWID=4-175-22-173670290-d...|toc ] .

      In the framework of a unique scheme of the proposed multiparticle effective field method, we have undertaken in this book an attempt to analyze the wide class of statical and dynamical, local and nonlocal, linear and nonlinear multiscale problems of composite materials with deterministic (periodic and nonperiodic), random (statistically homogeneous and inhomogeneous, so-called graded) and mixed (periodic structures with random imperfections) structures in bounded and unbounded domains, containing coated or uncoated inclusions of any shape and orientation and subjected to coupled or uncoupled, homogeneous or inhomogeneous external fields of different physical natures.

        Any the remarks and comments regarding the book will be fully appreciated.

Fang Wang's picture

BRAIN TEMPERATURE AND INTRACRANIAL PRESSURE – A QUANTITATIVE BIOLOGICAL-THERMAL-MECHANICAL PERSPECTIVE

The present paper studies the effect of intracranial temperature (ICT) change on intracranial pressure (ICP). Thermal and mechanical effects were analyzed using a 3D finite element model of the human head.

Xuejun Fan's picture

Fracture at corners or edges in bi-material systems

Dr. Suo's group is recently studying the sharp features such as corners or edges. It becomes important to characterize fracture behaviors at corners and edges in microelectronics.

I have two questions,

MichelleLOyen's picture

Dr. Kevin Granata

Kevin P. Granata, 45, of Blacksburg, beloved husband and father, loving son and brother, passed away Monday, April 16, 2007. Kevin was born and raised in Toledo, Ohio. He began his bachelor's studies at John Carroll University in Cleveland, Ohio and then transferred to Ohio State University where he received degrees in electrical engineering and physics. He later earned a Master's degree in physics from Purdue University and was employed by the Applied Physics Lab in Maryland where he did classified research. He returned to Ohio State University and completed his Ph. D. in Biomedical Engineering, continuing his research until he transferred to the Department of Orthopedics at the University of Virginia, where he was the director the Gait Lab In 2002, Kevin came to Virginia Tech in Blacksburg, Va. to continue his teaching and research interests. He had numerous publications and research grants and lectured both nationally and internationally. Kevin's greatest passion and pride was his family, especially his wife and children. He was also an athlete. He rowed crew at Purdue, participated in biathlons and triathlons and was an avid runner and cyclist. He loved coaching his sons' Lacrosse teams, reading and doing construction around his home and was a member of St. Mary's Roman Catholic Church. Kevin believed in being a well-rounded person and he successfully used his talents to the utmost, academically, physically and spiritually. He will be greatly missed. He is survived by wife, Linda (nee Ankenman); sons, Alex and Eric; and daughter, Ellen; parents, Mildred and Joseph Granata (Toledo); brother, Paul; sisters, Eileen and Anne; and numerous nieces and nephews, aunts and uncles. A public memorial service will be held at the Blacksburg Presbyterian Church at 2 p.m. Friday, April 20, 2007. A private funeral will be held. In lieu of flowers, memorials can be made to the Kevin P. Granata Memorial Trust, 1872 Pratt Drive, Blacksburg, Va, 24068. Arrangements by McCoy Funeral Home, 150 Country Club Drive, Blacksburg, Va.

Zhigang Suo's picture

Leaping Shampoo

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I came across this video of a fluid phenomenon today. I have no clue what caused it. If you know something about it, please explain to us.

Kyung-Suk Kim's picture

Sharing sadness for loss of dear friends and students

Upon hearing the painful news of VPI tragedy, I am deeply saddened that we lost our young students and fellow faculty, in particular, Liviu Librescu, G. V. Loganathan and Kevin Granata. I would like to share the sorrow with the family and friends of the victims who lost their lives in the senseless crime. I am deeply compelled to write this message, since I am a faculty teaching young students applied mechanics/engineering like professors Librescu, Loganathan and Granata, and belong to a small community of Korean Americans. I feel helpless and guilty that I could not mentor our young people and hear such incomprehensible tragic news.

JDI's picture

Science, 6, April, 2007 Direct-Current Nanogenerator Driven by Ultrasonic Waves

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What can we do in this discovery and creation?

By Xudong Wang, Jinhui Song, Jin Liu, Zhong Lin Wang*

Dr. Liviu Librescu (1930-2007)

Professor Dr. Liviu Librescu was murdered while teaching a solid mechanics course at Virginia Tech on April 16, 2007.

The great works he left behind are, including, but not limited to, the following books (which are the ones in English):

Seungtae Choi's picture

Scale bridging mechanics: Nanoscale planar field projection of atomic decohesion and slip in crystalline solids

I would like to introduce my recent paper on field projection method with Prof. K.-S. Kim at Brown University. When atomistic simulations or atomic resolution experiments are carried out to analyze deformation energetics of atomic lattices near a crack tip, the results of the atomic positions and the total energy of the system have not been systematically converted to field quantities such as stresses or tractions near the crack tip. In this study, we introduce a mathematically consistent way of defining and measuring the cohesive tractions, separations and surface stresses in an atomic decohesion process zone using the atomic displacement data at some distance away from the crack tip. The method is called “nano-scale planar field projection method.” This is a generalization of the method developed for isotropic homogeneous solids by Hong and Kim (2003). The formulation introduced here is applicable to interface cracks between anisotropic solids as well as to cracks in homogeneous solids whether they are anisotropic or isotropic. The field projection method is then applied to a crack tip field in gold, simulated atomistically. The atomistic simulation is made with an embedded atom method (EAM) potential for a crystal decohesion along [112] direction in a (111) plane. Then, the details of energy partition in various modes of nano-scale separation processes are analyzed with the field projection method.

Virginia Tech shootings take away two mechanicians

During the shootings occurred on the campus of Virginia Tech, the department of engineering science and mechanics lost two fine professors. Dr. Liviu Librescu was teaching solid mechanics class when the gunman initiated a two-minute massacre next door. Most of the students in his class escaped from the windows while Dr. Librescu held the door and did not survive when the gunman broke in. Another professor is Dr. Kevin Granata.

ericmock's picture

Virginia Tech Tragedy

With a great many ties to VT, I have been following the tragic shootings there closely. While my former student (Nakhiah Goulbourne) and my former department head (Dick Benson) are both safe, I am afraid we may have lost one of our own this morning. From an AP report, a student stated that the instructor teaching a 9:05am mechanics class in 204 Norris Hall was killed. According to the timetable of classes at VT, this instructor would have been Liviu Librescu. I certainly hope the AP's report is wrong. As someone very interested in shell theories, I have spoken with Prof. Librescu many times and followed his work. His loss would be a great loss to our community.

Ken P. Chong's picture

NSF CMMI RECRUITING FOR PROGRAM DIRECTORS

NATIONAL SCIENCE FOUNDATION

4201 WILSON BOULEVARD ARLINGTON, VA 22230

 

Title: Division of Civil, Mechanical and Manufacturing Innovation (CMMI)

Fang Wang's picture

BIOMECHANICAL STUDY OF GOLF BALL IMPACT ON CHILD’S HEAD USING THE FINITE ELEMENT METHOD

Head traumatic injury due to the impact of a flying golf ball is one of the severest injuries sustained on a golf course. This paper presents numerical simulation results based on the finite element (FE) method to investigate head injuries in children due to impacts by flying golf balls.

Some weekend reading

Terence Tao (one of the Fields Medal winners this year) has started blogging. He has a detailed discussion on the Navier-Stokes equations here. It's long but definitely worth reading - particularly because of the wide range of ideas that he talks about.

Pradeep Sharma's picture

J-club Editor: Election versus Appointment?

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As many of you know, last year we had a lively debate prior to the launch of the j-club regarding the rules and regulations governing the functioning of the j-club. This continued in a more low-key fashion this year. One of the more important topics under discussion has been the selection of the future editors (which is to be done each year). I, and perhaps a few other people, had reasoned that the editor should be elected by popular vote. It was proposed that candidates will either self-nominate themselves or be nominated by other mechanicians.

Vlado A. Lubarda's picture

The Leonhard Euler Tercentenary

Just a reminder that this Sunday, April 15 will be exactly 300 years since Leonhard Euler was born.

I am sure many mechanicians will toast this weekend on this extraordinnary anniversary to the person who laid down much of the foundations in mathematics and mechanics.

Some of the related links on the web are:

http://www.maa.org/Euler/

http://www.euler-2007.ch/en/

Srikar Vengallatore's picture

Symposium on Microelectromechanical Systems: Materials and Devices, MRS Fall 2007

From the Call for Papers: 

Microelectromechanical Systems (MEMS) represent the integration of miniaturized mechanical, chemical, fluidic, and optical devices with microelectronics. MEMS have a broad range of applications in optical- and radio-frequency communications, physical/chemical/biosensing, display technology, drug delivery, and the manipulation and isolation of cells.

MichelleLOyen's picture

Fundamentals of Nanoindentation and Nanotribology IV at MRS Fall 2007

First announcement and call for papers.

The symposium "Fundamentals of Nanoindentation and Nanotribology" will run for the fourth time at the Fall, 2007, Materials Research Society Meeting, Boston, MA, USA.   

Xiaodong Li's picture

On the uniqueness of measuring elastoplasticproperties from indentation

Indentation is widely used to measure material mechanical properties such as hardness, elastic modulus, and fracture toughness (for brittle materials). Can one use indentation to extract material elastoplastic properties directly from the measured force-displacement curves? Or simply, is it possible to obtain material stress-strain curves from the corresponding indentation load-displacement curves? In an upcoming paper in JMPS titled "On the uniqueness of measuring elastoplastic properties from indentation: The indistinguishable mystical materials," Xi Chen and colleagues at Columbia University and National Defense Academy, Japan show the existence of "mystical materials", which have distinct elastoplastic properties yet they yield almost identical indentation behaviors, even when the indenter angle is varied in a large range. These mystical materials are, therefore, indistinguishable by many existing indentation analyses unless extreme (and often impractical) indenter angles are used. The authors have established explicit procedures of deriving these mystical materials. In many cases, for a given indenter angle range, a material would have infinite numbers of mystical siblings, and the existence maps of the mystical materials are also obtained. Furthermore, they propose two alternative techniques to effectively distinguish these mystical materials. The study in this paper addresses the important question of the uniqueness of indentation test, as well as providing useful guidelines to properly use the indentation technique to measure material elastoplastic properties.

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