# dislocations

## Lecture 6: Introduction to Dislocations

These slides are used in a course on Plastic Deformation in Crystalline Solids.

## search for Petch's classic paper entitled "The cleavage strength of polycrystals"

Recently, I am reading several classic works on crystal plasticity. But, it seems to be difficult for me to obtain several very old papers in this area. For example, one of the classic papers on Hall-Petch relation,

Petch, N.J., The cleavage strength of polycrystals. The Iron and Steel Institute, 1953, 174: 25-28. I have tried many ways to get the original paper, but I finally failed. Could someone please send me a copy of this paper? Thanks a lot. Here is my email: dbliu2009@gmail.com

## Royalty Free Illustrations

Does anyone know of a good source for free science and engineering illustrations? I'm particularly interested in crystallography, crystal defects/dislocations, and mechanical properties illustrations.

Thanks

## Problems with numerical integration of discontinuous functions

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Hi everybody,

I am a very beginnerin doing research :-) and my topic is about "micro indentation analysis using continuum dislocation theory". I am applying high-order finite element method for this nonlinear problem.

My plan is first writing a subroutine for the element. However, when I intend to compute the internal force by using Gauss integration, I see a problem with the integrand function of some index of the internal force vector. This integrand is discontinuous function. It is therefore, I cannot get a good approximation with the standard Gauss integration.

## Problems with numerical integration of discontinuous functions

Hi everybody,

I am a beginner in doing research :-) and my topic is about "Micro Indentation Analysis using Continuum Dislocation Theory". I am applying high-order finite element method for this nonlinear problem.

My plan is first writing a subroutine for the element. However, when I intend to compute the internal force  by using Gauss Integration, I see a problem with the integrand function of some components of the internal force vector. This integrand is discontious function. It is therefore, I cannot get a good approximation with the standard Gauss integration.