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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。

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.

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.

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.

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.

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,

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.

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.

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.

In a recent Progress Article in Nature Materials, David Taylor, Jan G Hazenberg, and T Clive Lee write about the damage that human bones sustain as a result of cyclic stresses under which they operate and the repair mechanisms that operate.

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.

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.

NATIONAL SCIENCE FOUNDATION

4201 WILSON BOULEVARD ARLINGTON, VA 22230

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

This paper has been published in Journal of the Mechanics and Physics of Solids 56 (2008), pp. 1609-1623 (doi:10.1016/j.jmps.2007.07.013).

Abstract

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.

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.

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/