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What is the status of open source finite element code?

Submitted by Anonymous (not verified) on Mon, 11/20/2006 - 21:59

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FEMs are widely used in education, research, and industries. What is the prospect of having a vibrant community to evolve an open-source finite element code? What are the potential benefits for such a community and code? Has anybody tried?

Presumably whoever active in this effort may find support from government funding agencies and industries.

Meshfree Methods: Frequently Asked Questions

Submitted by John E. Dolbow on Mon, 11/20/2006 - 20:25

research

numerical methods

experts

Questions about meshfree methods are now addressed in the forum, under the Computational Mechanics subheading.

If you click on a question below, you will be redirected to the forum. I will update this post as more questions are added. Other experts are encouraged to augment my response there.

1. If I have meshfree shape functions that satisfy Kronecker-Delta, can I satisfy essential boundary conditions?

2. Is a mesh required in meshfree methods?

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Positioning on nanometer scale: fighting friction

Submitted by Anonymous (not verified) on Mon, 11/20/2006 - 15:32

industry

friction

Most friction models for automatic control are targeted for the macro world, and are of questionable value for the motion control of the high precision positioing stages. We published a paper recently in Technishes Messen (TM) on a study of the friction behavior in the moving range of micrometers. It provides info for the development of friction models targeted for the motion control in high precision engineering.

The following is the abstract, and the full paper can be downloaded from http://www.atypon-link.com/OLD/doi/abs/10.1524/teme.2006.73.9.500

ABSTRACT Most friction models for automatic control are targeted for the macro world, and are of questionable value for the motion control of the nanopositioning and nanomeasuring machine (NPM) system. We present the frictional behaviour of some selected materials, coatings, lubricants, and bearings tested under running conditions similar to a NPM system. Continuous change of surface properties results in various friction characteristics, which substantiate the further development of tribological coatings, particularly for vacuum applications. We emphasize the system engineering approach in developing friction models, which combines fundamental knowledge of surface science, materials science, and its applications in design, construction and automatic control.

2006 Timoshenko Medal Acceptance Speech by Kenneth L. Johnson

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Timoshenko Medal

acceptance speech

Presented at the Applied Mechanics Dinner of the 2006 Winter Annual Meeting of ASME, Hilton Chicago Hotel, 9 November 2006.

First and formost, I must acknowledge with gratitude the honour of being selected for the Timoshenko medal for 2006. But since a speech is now expected, I realise that this is not free lunch. If you know a good pub, this would be a good time to slip away.

When I received Virgil Carter's letter informing me that I had been selected, I could not believe it. There must have been a mistake; after all Johnson is a very common name. I am reminded of my first meeting with Bernie Budiansk from Harvard, also a Timoshenko medallist. He asked, "Did you write that book on vibration with Bishop?" "No. That was Dan Johnson"; " Did you edit that British Journal of mechanical sciences?": "No. That was Bill Johnson"; "Who the hell are you!"

A Recent Book: Meshfree Particle Methods, by Shaofan Li and Wing-Kam Liu

Submitted by shaofanli on Mon, 11/20/2006 - 07:51

education

Meshfree Particle Methods is a comprehensive and systematic exposition of particle methods, meshfree Galerkin and partition of unity methods, molecular dynamics methods, and multiscale methods. It presents theoretical foundation, numerical algorithms, as well as applications. Since it was published in 2004, the first print has been sold out. The publisher is preparing the second print.

Eshelby and his two classics (and some more on the side)

Submitted by Mogadalai Gururajan on Sun, 11/19/2006 - 12:45

Eshelby and the inclusion/inhomogeneity problems

Any materials scientist interested in mechanical behaviour would be aware of the contributions of J.D. Eshelby. With 56 papers, Eshelby revolutionised our understanding of the theory of materials. The problem that I wish to discuss in this page is the elastic stress and strain fields due to an ellipsoidal inclusion/inhomogeneity - a problem that was solved by Eshelby using an elegant thought experiment.

In two papers published in the Proceedings of Royal Society (A) in 1957 and 1959 (Volume 241, p. 376 and Volume 252, p. 561) Eshelby solved the following problem ("with the help of a simple set of imaginary cutting, straining and welding operations"): In his own words,

S. Germain, "Memoir on the Vibrations of Elastic Plates"

Submitted by MichelleLOyen on Sun, 11/19/2006 - 11:10

elasticity

vibration

plate

I have not read the above-mentioned paper, as I have never been able to find it. However it is said to be "a brilliantly insightful paper which was to lay the foundations of modern elasticity." However, I believe it is also noteworthy for being one of the major contributions by a female mechanician prior to the modern era. For a great biography of Sophie Germain, including a fantastic quote from a letter from Carl Gauss on discovering that she was female--and not "Monsieur Le Blanc"--visit this site (from which the above quote, on the impact of her paper, came).

There are no female mechanicians listed on http://en.wikipedia.org/wiki/Mechanicians but I believe it could be argued that Germain deserves a mention!

New Book: Computer Simulations of Dislocations, by Vasily V. Bulatov and Wei Cai

Submitted by Cai Wei on Sun, 11/19/2006 - 01:18

Companion web site http://micro.stanford.edu ISBN:0-19-852614-8, Hard cover, 304 pages, Nov. 2006, US $74.50.

This book presents a broad collection of models and computational methods - from atomistic to continuum - applied to crystal dislocations. Its purpose is to help students and researchers in computational materials sciences to acquire practical knowledge of relevant simulation methods. Because their behavior spans multiple length and time scales, crystal dislocations present a common ground for an in-depth discussion of a variety of computational approaches, including their relative strengths, weaknesses and inter-connections. The details of the covered methods are presented in the form of "numerical recipes" and illustrated by case studies. A suite of simulation codes and data files is made available on the book's website to help the reader "to learn-by-doing" through solving the exercise problems offered in the book. This book is part of an Oxford Series on Materials Modelling.