DYNAMIC PLASTICITY
P}`H ~N~ 9k[9P;"F: Copyright © 2007 by World Scientific Publishing Co. Pte. Ltd
9]o-O]7/ , SnSW -P The present book is not simply a new addition of the book Dynamic Plasticity,
*s iFj
CN< initially published in 1967, a long time ago. Certainly this edition is not only a new
Xm2z}X(% version, containing the essential of the old book and what has been done meantime.
`n?DU;, Why again Dynamic Plasticity? Well because very many books published meantime
Nu~lsWyRI5 on the subject are not mentioning the waves which are to be considered in Dynamic
&Z|P2 dI Plasticity. Also, generally, the plastic waves are slower than the elastic one. Thus,
1]/.` ]1 when considering a simple problem of propagation of waves in thin bars, for any
j^2j& Ta loading at the end, the plastic waves are reached by the elastic ones, and will not
4]}'Hln*U propagate any more. Only a part of the bar is deforming plastically. Examples of
t#eTV@- this kind are very few.
&~U ] ~;@ I thought that this new version is too restrictive for the today students which
{U !g.rh know little of static plasticity, differential equations, dynamic elastic–plastic properties,
}?v )N).kW etc. Therefore, I thought to write a simpler book, containing the main
K@w{"7} concepts of dynamic plasticity, but also something else. Thus I thought that this
m/EFHS49 new version would contain the elementary concepts of static plasticity, etc., which
^@NU}S):yN would be useful to give. Also it would be good to give other problems, not directly
D*|Bb? related to dynamic plasticity. Thus I started with some classical problems on
`&6dnSC},P static plasticity, but only the simplest things, so that the readers would afterwards
ZO$%[ftb understand also the dynamic problems. Also, since in dynamic problems the soils
[Cv/{f3]u{ and rocks played a fundamental role, I thought to write a chapter on rocks and soils.
x;<W&s}( Then were expressed several chapters about dynamic plasticity, as propagation of
kX2rp?{ elastic–plastic waves in thin bars, the rate influence and the propagation of waves
f ZA4q0 in flexible strings. It is good to remember here that all problems related to dynamic
{h`uV/5@` problems, are to be considered using the mechanics of the wave propagation; without
-v|qZ' the wave propagation mechanics all results concerning constitutive equations,
R@k&SlL'` rate effect, etc. are only informative. Such problems are mentioned however in the
R hLVg~x book. We have presented mainly the different aspects on constitutive equations of
kt$jm)UI~l materials, as resulting from dynamic problems. Rate effects are considered in this
%z 4Nl$\ way. They have been used by a variety of authors. The same with the mechanics of
T 0rG M flexible strings, presented afterwards. Not very many authors have considered till
W-zP/]Dh now the mechanics of deformable cables.
<B8!.|19 Therefore I thought to write a very simple book, which can be read by the
Ck7uJI<x students themselves, without any additional help. They can understand what
e.V:)7Uc “plasticity” is after all. Then several other problems have been presented. Not
"C0Q(dr/n trying to remove the fundamentals, I have thought also to add some additional
h2 ;F problems, which are in fact dynamic, though the inertia effect is disregarded. They
%;YHt=(1*X are the stationary problems, quite often met in many applications. It is question
fMyti$1~ obviously, about problems involving Bingham bodies, as wire drawing, floating with
J!U}iD@occ working plug, extrusion, stability of natural inclined plane, etc.
)~ h} Further I have considered various problems of plastic waves, using various
n t7.?$ theories. Also the perforation problems, was presented, using various symmetry
A X/m25x assumptions, or any other assumption made.
ZoZ| M a The last chapter is on hypervelocity impact. To keep it simple, I have given
2WxQ(:d= only very few information about. Thus I wished to show what hypervelocity is and
$aXer: how is it considered now.
$,Yd>%Y Though the book is a very simple one, I wished to ask any author to disregard
Dy8r 9 possible missing of some papers. All literature is certainly incomplete. One has
.gOL1`b* done today much more than given here. It was impossible for me to mention “all”
s>n)B^64W authors in this field.
2Dj%,gaR N. D. Cristescu
ThbGQ"/ cristesc@ufl.edu
