It is commonly assumed that grain boundary sliding can control plastic deformation in fine grained crystalline solids. Superplasticity is often considered to be controlled by grain boundary sliding, for example. I have never accepted that view, though my own opinion is very much at odds with the commonly accepted picture. When I was asked to write a paper in honor of Professor F.R.N. Nabarro's 90th birthday (Prof.
The attached file is a set of class notes developed by W.D. Nix of Stanford University and used in a graduate course on Mechanical Properties of Thin Films. These notes have been used in the graduate course MSE 353 since the late 1980's. That course has been taught every year or so since that time. The notes were last updated in January of 2005. The reader will see a note to the effect that many of the figures and illustrations in the file have been taken from the work of students and colleagues at Stanford without proper attribution.
McMat 2007, June 3-7, 2007, University of Texas at Austin
Call for paper
Symposium: Multiscale Multiphysics Modeling and Simulation of Nanomaterials and Nanostructures
So, What is Mechanics? It seems that useful answers ought to depend on who you are talking to. If you are persuading your dean to hire a new faculty member in Mechanics, perhaps you’d like to point out promising research in one area or another, and how foundational mechanics is to the education of future scientists and technologists in (almost) all fields.
In the present time the internet craze has swept the nation and these days everything and everyone is online. Everyone having fun on internet and get knowledge from the web site.
If you want to know how to make a free web site, the good news is that you've set an easy goal for yourself. Learning how to make a free web site is about more than just getting your web domain for free - you need to know how to put information on that site as well. Many domains offering free web sites also feature free online tutorials that will help you write your web pages. Some sites are so user-friendly; you don't have to write any of your own web code at all! You can select colors and font sizes from the domain's own page editing service. When the domain is willing to write your pages for you, it's very easy to learn how to make a free web site.
Who owns your content? Is it you or the copyright holder? If it isn't you, then why did you pay for it? All these questions are at the heart of the current war for the rights to music, movies, and everything in between.
The first shots of this war were fired with the start of the digital age. Before, the best you could was make physical copies of media. Technically possible, yes, but the equipment and manpower needed to run an operation on a scale large enough to threaten publishers was nearly impossible to obtain without being noticed.
Recently, during one of my net searches, I came across this page of RPI, where I learnt about a couple of numerical mechanics software which might be of interest to some of you.
FMDB:
As for the effort toward the scalable engineering simulations on distributed environements, we addressed this challenge by developing a distributed mesh data management infrastructure that satisfies the needs of distributed domain of applications.
This is a paper by Jizhong Lou and myself, which is in press in Biophysical Journal.
Abstract. Catch bonds, whose lifetimes are prolonged by force, have been observed in selectin-ligand interactions and other systems. Several biophysical models have been proposed to explain this counter-intuitive phenomenon, but none was based on the structure of the interacting molecules and the noncovalent interactions at the binding interface. Here we used molecular dynamics simulations to study changes in structure and atomic-level interactions during forced unbinding of P-selectin from P-selectin glycoprotein ligand-1. A mechanistic model for catch bonds was developed based on these observations. In the model, "catch" results from forced opening of an interdomain hinge that tilts the binding interface to allow two sides of the contact to slide against each other. Sliding promotes formation of new interactions and even rebinding to the original state, thereby slowing dissociation and prolonging bond lifetimes. Properties of this sliding-rebinding mechanism were explored using a pseudo-atom representation and Monte Carlo simulations. The model has been supported by its ability to fit experimental data and can be related to previously proposed two-pathway models.
We know - or believe - protein function is determined by structure. Crystallographic and NMR studies can provide protein structures with atomic-level details at equilibrium. MD simulations can follow protein conformational changes in time with fs temporal resolution in the absence or presence of a bias mechanism, e.g., applied force, used to induce such changes.
This is a paper that has been accepted for publication in the Journal of the Mechanics and Physics of Solids from our group. The paper describes the combined effect of material inertia and inhomogeneous material property variation on spontaneous cohesive-crack propagation in functionally graded materials. The preprint is attached as a PDF.
Abstract- The effects of combining functionally graded materials of different inhomogeneous property gradients on the mode-3 propagation characteristics of an interfacial crack are numerically investigated. Spontaneous interfacial crack propagation simulations were performed using the newly developed spectral scheme. The numerical scheme derived and implemented in the present work can efficiently simulate planar crack propagation along functionally graded bimaterial interfaces. The material property inhomogeneity was assumed to be in the direction normal to the interface. Various bimaterial combinations were simulated by varying the material property inhomogeneity length scale. Our parametric study showed that the inclusion of a softening type functionally graded material in the bimaterial system leads to a reduction in the fracture resistance indicated by the increase in crack propagation velocity and power absorbed. An opposite trend of increased fracture resistance was predicted when a hardening material was included in the bimaterial system. The cohesive tractions and crack opening displacements were altered due to the material property inhomogeneity, but the stresses ahead of the cohesive zone remained unaffected.
