configurational forces

Twenty years in since their introduction, it is now plain that the regularized formulations dubbed as phase-field of the variational theory of brittle fracture of Francfort and Marigo (1998) provide a powerful macroscopic theory to describe and predict the propagation of cracks in linear elastic brittle materials under arbitrary quasistatic loading conditions. Over the past ten years, the ability of the phase-field approach to also possibly describe and predict crack nucleation has been under intense investigation.

We present a unified classical treatment of partially constrained elastic rods. Partial constraints often entail singularities in both shapes and reactions. Our approach encompasses both sleeve and adhesion problems, and provides simple and unambiguous derivations of counterintuitive results in the literature. Relationships between reaction forces and moments, geometry, and adhesion energies follow from the balance of energy during quasistatic motion. We also relate our approach to the configurational balance of material momentum and the concept of a driving traction.

Can a torque induce longitudinal motion of an elastic rod?

See the explanation and an example of use of the 'torsional gun' at http://www.ing.unitn.it/~bigoni/torsional_locomotion.html

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What is stress? Who has ever seen stress? Is stress a physical quantity?

Professor Yi-Heng Chen, Xi’an Jiaotong University, 710049, P.R.China

e-mail: yhchen2 [at] mail.xjtu.edu.cn (yhchen2[at]mail[dot]xjtu[dot]edu[dot]cn)

In fact, this question has been bothering the present author for more than 15 years.

*This issue of the Journal Club has been prepared as a group by Ankush Aggarwal, Mo Bai, Mainak Sarkar, and Jee E Rim, and with comments and suggestions from Bill Klug .

The Solid Mechanics group of the University of Trento (Italy) announces ISDMM09, the fourth international meeting devoted to Mechanics of Material Forces, following the workshops held at Kaiserslautern (2003), Symi (2005) and Aussois (2007), and will be held in the alpine city of Trento, Italy, from July 6^th to 9^th, 2009.

Abstract submission: January 31, 2009

More info: http://portale.unitn.it/events/isdmm09