DYNAMIC PLASTICITY
0R; ;ou 6.k2,C4dT< Copyright © 2007 by World Scientific Publishing Co. Pte. Ltd
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a|OX 4 The present book is not simply a new addition of the book Dynamic Plasticity,
|i|>-|`! initially published in 1967, a long time ago. Certainly this edition is not only a new
1_F2{n:y p version, containing the essential of the old book and what has been done meantime.
7 6hi@ 7a Why again Dynamic Plasticity? Well because very many books published meantime
H*!E*_ on the subject are not mentioning the waves which are to be considered in Dynamic
}3QEclZr Plasticity. Also, generally, the plastic waves are slower than the elastic one. Thus,
n0cqM}P@;! when considering a simple problem of propagation of waves in thin bars, for any
Y(- +>>j_ loading at the end, the plastic waves are reached by the elastic ones, and will not
pV1~REk$& propagate any more. Only a part of the bar is deforming plastically. Examples of
z S^:Ng5 this kind are very few.
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]P I thought that this new version is too restrictive for the today students which
05w_/l+ know little of static plasticity, differential equations, dynamic elastic–plastic properties,
;ASlsUE\) etc. Therefore, I thought to write a simpler book, containing the main
Q.!D2RZc concepts of dynamic plasticity, but also something else. Thus I thought that this
+.zriiF]i new version would contain the elementary concepts of static plasticity, etc., which
9]|cs would be useful to give. Also it would be good to give other problems, not directly
p! Hpq W related to dynamic plasticity. Thus I started with some classical problems on
a*o =,! static plasticity, but only the simplest things, so that the readers would afterwards
aiz_6@Qfz* understand also the dynamic problems. Also, since in dynamic problems the soils
[5,#p $R and rocks played a fundamental role, I thought to write a chapter on rocks and soils.
e O*F oN Then were expressed several chapters about dynamic plasticity, as propagation of
`~gyq>Ik2 elastic–plastic waves in thin bars, the rate influence and the propagation of waves
|J8c|h< in flexible strings. It is good to remember here that all problems related to dynamic
0 (64}T) problems, are to be considered using the mechanics of the wave propagation; without
Y>IEB,w the wave propagation mechanics all results concerning constitutive equations,
-l^ u1z rate effect, etc. are only informative. Such problems are mentioned however in the
ZX'/[wAN) book. We have presented mainly the different aspects on constitutive equations of
2o6 %P}C materials, as resulting from dynamic problems. Rate effects are considered in this
/9i2@#J}W1 way. They have been used by a variety of authors. The same with the mechanics of
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flexible strings, presented afterwards. Not very many authors have considered till
Qxt ,@<IK now the mechanics of deformable cables.
l .FkX Therefore I thought to write a very simple book, which can be read by the
g#:?Ay-m students themselves, without any additional help. They can understand what
2'N%KKmJL “plasticity” is after all. Then several other problems have been presented. Not
3>-^/ trying to remove the fundamentals, I have thought also to add some additional
+$ P0&YaQ problems, which are in fact dynamic, though the inertia effect is disregarded. They
-cOLg rmp are the stationary problems, quite often met in many applications. It is question
V:yia^1 obviously, about problems involving Bingham bodies, as wire drawing, floating with
zs WYV n] working plug, extrusion, stability of natural inclined plane, etc.
1*#64Y5F Further I have considered various problems of plastic waves, using various
`vUilh ^c theories. Also the perforation problems, was presented, using various symmetry
RtN5\ assumptions, or any other assumption made.
EdLbVrN, The last chapter is on hypervelocity impact. To keep it simple, I have given
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\ only very few information about. Thus I wished to show what hypervelocity is and
1_f( ;WOg how is it considered now.
\y{C>! WX4 Though the book is a very simple one, I wished to ask any author to disregard
J](AJkGzK possible missing of some papers. All literature is certainly incomplete. One has
)] ?sCNb done today much more than given here. It was impossible for me to mention “all”
iz& )FuOr authors in this field.
EW|bs#l N. D. Cristescu
IL&Mf9m cristesc@ufl.edu
