DYNAMIC PLASTICITY
lt:&lIW,3 SSE,G!@ Copyright © 2007 by World Scientific Publishing Co. Pte. Ltd
~uZ9%UB_m _xi &%F/ The present book is not simply a new addition of the book Dynamic Plasticity,
CALD7qMK initially published in 1967, a long time ago. Certainly this edition is not only a new
sn^ 3xAF version, containing the essential of the old book and what has been done meantime.
W% Lrp{ Why again Dynamic Plasticity? Well because very many books published meantime
',WJ'g on the subject are not mentioning the waves which are to be considered in Dynamic
+4T.3Njjn Plasticity. Also, generally, the plastic waves are slower than the elastic one. Thus,
=LK`m NA when considering a simple problem of propagation of waves in thin bars, for any
c7@/<*E+ loading at the end, the plastic waves are reached by the elastic ones, and will not
qM26 :kB{ propagate any more. Only a part of the bar is deforming plastically. Examples of
-X7 x~x- this kind are very few.
^q/^.Gf I thought that this new version is too restrictive for the today students which
}wv R s5;o know little of static plasticity, differential equations, dynamic elastic–plastic properties,
1D8S }=5& etc. Therefore, I thought to write a simpler book, containing the main
ts@$* concepts of dynamic plasticity, but also something else. Thus I thought that this
SIR2 Kc0 new version would contain the elementary concepts of static plasticity, etc., which
qk3 ~]</ would be useful to give. Also it would be good to give other problems, not directly
h>[ qXz related to dynamic plasticity. Thus I started with some classical problems on
_ eBNbO_J static plasticity, but only the simplest things, so that the readers would afterwards
D A>nYj-s understand also the dynamic problems. Also, since in dynamic problems the soils
Y:m8UnT and rocks played a fundamental role, I thought to write a chapter on rocks and soils.
zZRLFfz<9 Then were expressed several chapters about dynamic plasticity, as propagation of
L&:A59)1k elastic–plastic waves in thin bars, the rate influence and the propagation of waves
StTxga| in flexible strings. It is good to remember here that all problems related to dynamic
i>CR {q problems, are to be considered using the mechanics of the wave propagation; without
8?kB+}@6X the wave propagation mechanics all results concerning constitutive equations,
iiJT%Zq`# rate effect, etc. are only informative. Such problems are mentioned however in the
Lk#)VGk: book. We have presented mainly the different aspects on constitutive equations of
K3tW Y
4- materials, as resulting from dynamic problems. Rate effects are considered in this
_4SZ9yu way. They have been used by a variety of authors. The same with the mechanics of
UukY9n];] flexible strings, presented afterwards. Not very many authors have considered till
/c-k{5mH% now the mechanics of deformable cables.
+,ar`:x &a Therefore I thought to write a very simple book, which can be read by the
V?x&\< ;, students themselves, without any additional help. They can understand what
d#bg(y\G| “plasticity” is after all. Then several other problems have been presented. Not
=+T0[|gc(r trying to remove the fundamentals, I have thought also to add some additional
#<m2Xo?d] problems, which are in fact dynamic, though the inertia effect is disregarded. They
P(8
u L|^ are the stationary problems, quite often met in many applications. It is question
md18q:AG) obviously, about problems involving Bingham bodies, as wire drawing, floating with
mSu$1m8 working plug, extrusion, stability of natural inclined plane, etc.
tS3&&t Further I have considered various problems of plastic waves, using various
wG)[Ik6: theories. Also the perforation problems, was presented, using various symmetry
5MCgmF*Y2 assumptions, or any other assumption made.
{ 6qxg _{ The last chapter is on hypervelocity impact. To keep it simple, I have given
<6+B;brh only very few information about. Thus I wished to show what hypervelocity is and
U*sQ 5uq how is it considered now.
b3%a4Gg& Though the book is a very simple one, I wished to ask any author to disregard
|r;>2b/ x possible missing of some papers. All literature is certainly incomplete. One has
<'sm($.2 done today much more than given here. It was impossible for me to mention “all”
5?
Y(FhnIC authors in this field.
m
zoH$@ N. D. Cristescu
k$J!, !q cristesc@ufl.edu
