A typical two phase microstructure consists of a topologically continuous `matrix' phase in which islands of `precipitate' phase are embedded. Usually, the matrix phase is also the majority phase in terms of volume fraction. However, sometimes this relationship between the volume fraction and topology is reversed, and this reversal is known as phase inversion. Such a phase inversion can be driven by an elastic moduli mismatch in two-phase solid systems. In this paper (submitted to Philosophical magazine), we show phase inversion, and the effect of the elastic moduli mismatch and elastic anisotropy on such inversion.
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.
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.
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
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
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.
Please joint me in congratulatingDr. Stelios Kyriakides’ (Editor of International Journal of Solids and Structures) for his election to the United States National Academy of Engineering.
Since Dec. 2006, Institute of High Performance Computing (IHPC) has set up a biophysics research team that comprises research scientists in the fields of biophysics, solid mechanics and fluid mechanics, and has kicked off the "Computational Cancer Mechanics" project.
I was reading professor Zhigang Suo's post titled "What's Wrong with Applied Mechanics", thinking about the large amount of knowledge available. There are so many applications of mechanics that they seem endless in any subfield that one can think of. It made me recall some homework problems that wanted to include real life applications. However, real life applications tend to turn out much more complicated than what can be covered in one homework problem.
The strength and hardness of some metal alloys may be enhanced by the formation of extremely small uniformly dispersed particles of a second phase within the original phase matrix; this must be accomplished by appropriate heat treatment.
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