DYNAMIC PLASTICITY
f x:vhE X >q')%j Copyright © 2007 by World Scientific Publishing Co. Pte. Ltd
2./ z6jXW_ 7aRy])x The present book is not simply a new addition of the book Dynamic Plasticity,
;B< rw ^h5 initially published in 1967, a long time ago. Certainly this edition is not only a new
8 bw, dBN version, containing the essential of the old book and what has been done meantime.
+U'n|>t9 Why again Dynamic Plasticity? Well because very many books published meantime
Lcg1X3$G on the subject are not mentioning the waves which are to be considered in Dynamic
jn]l!nm Plasticity. Also, generally, the plastic waves are slower than the elastic one. Thus,
rD6NUS when considering a simple problem of propagation of waves in thin bars, for any
8xj_)=(sV! loading at the end, the plastic waves are reached by the elastic ones, and will not
{y|.y~vW propagate any more. Only a part of the bar is deforming plastically. Examples of
}<z [t5 this kind are very few.
"1d pv \ I thought that this new version is too restrictive for the today students which
"tb KbFn9 know little of static plasticity, differential equations, dynamic elastic–plastic properties,
-0'< 7FSQ etc. Therefore, I thought to write a simpler book, containing the main
g \+!+!"~ concepts of dynamic plasticity, but also something else. Thus I thought that this
Mu.t q~b > new version would contain the elementary concepts of static plasticity, etc., which
8eCh5*_$ would be useful to give. Also it would be good to give other problems, not directly
Q(WfWifu-| related to dynamic plasticity. Thus I started with some classical problems on
3]NKAPY static plasticity, but only the simplest things, so that the readers would afterwards
6."|m+D understand also the dynamic problems. Also, since in dynamic problems the soils
'D[ *|Qcy and rocks played a fundamental role, I thought to write a chapter on rocks and soils.
ko{&~ Then were expressed several chapters about dynamic plasticity, as propagation of
e MOp}.zt| elastic–plastic waves in thin bars, the rate influence and the propagation of waves
1@-l@ P in flexible strings. It is good to remember here that all problems related to dynamic
YY>&R'3[ problems, are to be considered using the mechanics of the wave propagation; without
i'ZnU55= the wave propagation mechanics all results concerning constitutive equations,
1JS5 LS rate effect, etc. are only informative. Such problems are mentioned however in the
%} book. We have presented mainly the different aspects on constitutive equations of
?+c-m+;wj materials, as resulting from dynamic problems. Rate effects are considered in this
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06T_4o way. They have been used by a variety of authors. The same with the mechanics of
#VZ-gy4$\B flexible strings, presented afterwards. Not very many authors have considered till
8XfOM f~d` now the mechanics of deformable cables.
.lgm " Therefore I thought to write a very simple book, which can be read by the
\*fXPJ4 students themselves, without any additional help. They can understand what
.dc|?$XV “plasticity” is after all. Then several other problems have been presented. Not
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+f trying to remove the fundamentals, I have thought also to add some additional
R{B5{~m>W@ problems, which are in fact dynamic, though the inertia effect is disregarded. They
gYpFF=7j<@ are the stationary problems, quite often met in many applications. It is question
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$}r0U obviously, about problems involving Bingham bodies, as wire drawing, floating with
f'j<v working plug, extrusion, stability of natural inclined plane, etc.
ASS<XNP Further I have considered various problems of plastic waves, using various
(6)|v S theories. Also the perforation problems, was presented, using various symmetry
!}d_$U$ assumptions, or any other assumption made.
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f[1> The last chapter is on hypervelocity impact. To keep it simple, I have given
r"7 !J[u only very few information about. Thus I wished to show what hypervelocity is and
mt *Dx how is it considered now.
47 &p*= Though the book is a very simple one, I wished to ask any author to disregard
KrTlzbw&p\ possible missing of some papers. All literature is certainly incomplete. One has
meD83,L~N done today much more than given here. It was impossible for me to mention “all”
`'rvDaP authors in this field.
#E/|W T N. D. Cristescu
H'@@%nO ( cristesc@ufl.edu
