During solid-solid phase transformations elastic stresses arise due to a difference in lattice parameters between the constituent phases. These stresses have a strong influence on the resultant microstructure and its evolution; more specifically, if there be externally applied stresses, the interaction between the applied and the transformation stresses can lead to rafting.
Backus died recently. This New York Times article reminds us of why Fortran was such a great innovation.
From an engineering point of view, prediction of fatigue crack nucleation in automotive rubber parts is an essential prerequisite for the design of new components. We have derived a new predictor for fatigue crack nucleation in rubber. It is motivated by microscopic mechanisms induced by fatigue and developed in the framework of Configurational Mechanics. As the occurrence of macroscopic fatigue cracks is the consequence of the growth of pre-existing microscopic defects, the energy release rate of these flaws need to be quantified. It is shown that this microstructural evolution is governed by the smallest eigenvalue of the configurational (Eshelby) stress tensor. Indeed, this quantity appears to be a relevant multiaxial fatigue predictor under proportional loading conditions. Then, its generalization to non-proportional multiaxial fatigue problems is derived. Results show that the present predictor, which covers the previously published predictors, is capable to unify multiaxial fatigue data.
To the students of ES 241:
Although finite deformation was introduced in ES 240 (Solid Mechanics), finite deformation is a building block of ES 241. To review the subject, please go over a set of problems compiled by Jim Rice. If you need a reference, see my outline of finite deformation, where you can also find a short list of textbooks.
With the increasing use of shape memory alloys in recent years, it is important to investigate the effect of cracks. Theoretically, the stress field near the crack tip is unbounded. Hence, a stress-induced transformation occurs, and the martensite phase is expected to appear in the neighborhood of the crack tip, from the very first loading step. In that case, the crack tip region is not governed by the far field stress, but rather by the crack tip stress field. This behavior implies transformation toughening or softening.
This paper shows that the stress field in the classical theory of continuum mechanics
may be taken to be a covector-valued differential two-form. The balance laws and other funda-
mental laws of continuum mechanics may be neatly rewritten in terms of this geometric stress. A
This set of homework is on mixed mode fracture and interfacial fracture
Springer - in an attempt to get customers I suppose - are offering free access to the journal Computational Mechanics, but only for March 2007.
You can access all articles in Computational Mechanics back to vol 1/1, e.g. the first article
E. Reissner
Some aspects of the variational principles problem in elasticity
Volume 1, Issue - 1, First Page - 3, Last Page - 9
DOI - 10.1007/BF00298634
Link - http://www.springerlink.com/content/t52w761088542m68
To get the free access (for the rest of March) go to
http://scientific-direct.net/c.asp?id=650015&c=7fbfc8d9b40ac978&l=31
Buckling delamination, with two slides on 1D vonKarman plates.
Update 23 March 2007. This wonderful educational video has now been removed from YouTube because it violates copyright. What a pity!
Andre of Biocurious has just pointed out this terrific animation of the dynamics inside a cell. It brings many pages of textbook to life. Delightful. I've just followed Teng Li's instruction to embed the YouTube video below.
