DYNAMIC PLASTICITY
5D s[? ]4~Yi1] Copyright © 2007 by World Scientific Publishing Co. Pte. Ltd
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>a X4!9 3 The present book is not simply a new addition of the book Dynamic Plasticity,
UB~K/r`.| initially published in 1967, a long time ago. Certainly this edition is not only a new
DYX{v`>f^ version, containing the essential of the old book and what has been done meantime.
.ARYCTyG Why again Dynamic Plasticity? Well because very many books published meantime
y4\X~5kU on the subject are not mentioning the waves which are to be considered in Dynamic
iSfRJ:_&6 Plasticity. Also, generally, the plastic waves are slower than the elastic one. Thus,
44CZl{pt when considering a simple problem of propagation of waves in thin bars, for any
[8Z DMe loading at the end, the plastic waves are reached by the elastic ones, and will not
HG"ZN)~ propagate any more. Only a part of the bar is deforming plastically. Examples of
RhYe=Qh4{p this kind are very few.
~DH 9i B I thought that this new version is too restrictive for the today students which
EKc<|e, F know little of static plasticity, differential equations, dynamic elastic–plastic properties,
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$vm etc. Therefore, I thought to write a simpler book, containing the main
=<\22d5L concepts of dynamic plasticity, but also something else. Thus I thought that this
R~<N*En~ new version would contain the elementary concepts of static plasticity, etc., which
}i9:k kfq2 would be useful to give. Also it would be good to give other problems, not directly
HwU9 y related to dynamic plasticity. Thus I started with some classical problems on
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2 static plasticity, but only the simplest things, so that the readers would afterwards
FgdnX2s J understand also the dynamic problems. Also, since in dynamic problems the soils
cXX Z'y>FP and rocks played a fundamental role, I thought to write a chapter on rocks and soils.
IIk_! VzT Then were expressed several chapters about dynamic plasticity, as propagation of
jN6V`Wh_ elastic–plastic waves in thin bars, the rate influence and the propagation of waves
\zd[A~! in flexible strings. It is good to remember here that all problems related to dynamic
rrIyZ@_d9 problems, are to be considered using the mechanics of the wave propagation; without
A}fm).W p@ the wave propagation mechanics all results concerning constitutive equations,
7cc^n\c?Y rate effect, etc. are only informative. Such problems are mentioned however in the
-jQ*r$iRE book. We have presented mainly the different aspects on constitutive equations of
txEN7! materials, as resulting from dynamic problems. Rate effects are considered in this
b'4a;k!rS way. They have been used by a variety of authors. The same with the mechanics of
@&T' h}|: flexible strings, presented afterwards. Not very many authors have considered till
C-pR$WM:HN now the mechanics of deformable cables.
\ g0vzo"u Therefore I thought to write a very simple book, which can be read by the
9.)z]Gav students themselves, without any additional help. They can understand what
zC50 @S3| “plasticity” is after all. Then several other problems have been presented. Not
5(~Lr3v0 trying to remove the fundamentals, I have thought also to add some additional
kBP?_ O problems, which are in fact dynamic, though the inertia effect is disregarded. They
[ $3+5K# are the stationary problems, quite often met in many applications. It is question
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<K - obviously, about problems involving Bingham bodies, as wire drawing, floating with
sRB=<E*_ working plug, extrusion, stability of natural inclined plane, etc.
5OM #_.p Further I have considered various problems of plastic waves, using various
AKk=XAGW theories. Also the perforation problems, was presented, using various symmetry
b'wy{~l@ assumptions, or any other assumption made.
he|Q ( ? The last chapter is on hypervelocity impact. To keep it simple, I have given
D:`Q \za only very few information about. Thus I wished to show what hypervelocity is and
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x#M!os0 how is it considered now.
{S 0-y Though the book is a very simple one, I wished to ask any author to disregard
|bk9< i ? possible missing of some papers. All literature is certainly incomplete. One has
r8"2 C# done today much more than given here. It was impossible for me to mention “all”
_'D(>e? authors in this field.
%oBP6|e N. D. Cristescu
MlTC?Rp # cristesc@ufl.edu
