DYNAMIC PLASTICITY
;RWW+x8 IB Kajkw>z Copyright © 2007 by World Scientific Publishing Co. Pte. Ltd
y)3~]h\a 4? m/*VV The present book is not simply a new addition of the book Dynamic Plasticity,
5N oe/6 initially published in 1967, a long time ago. Certainly this edition is not only a new
`*e 4m version, containing the essential of the old book and what has been done meantime.
6R ;) Why again Dynamic Plasticity? Well because very many books published meantime
6P;o 6s on the subject are not mentioning the waves which are to be considered in Dynamic
M!N`
Orz Plasticity. Also, generally, the plastic waves are slower than the elastic one. Thus,
4 ,p#:! when considering a simple problem of propagation of waves in thin bars, for any
ycgfZ 3K loading at the end, the plastic waves are reached by the elastic ones, and will not
L]k*QIn:h propagate any more. Only a part of the bar is deforming plastically. Examples of
gB]C&Q this kind are very few.
g!1I21M1~ I thought that this new version is too restrictive for the today students which
Mn]}s:v know little of static plasticity, differential equations, dynamic elastic–plastic properties,
jrm0@K+<IA etc. Therefore, I thought to write a simpler book, containing the main
2c}B concepts of dynamic plasticity, but also something else. Thus I thought that this
YXF #c)# new version would contain the elementary concepts of static plasticity, etc., which
44|deE3Z would be useful to give. Also it would be good to give other problems, not directly
YF} 9k related to dynamic plasticity. Thus I started with some classical problems on
sA/,+aM static plasticity, but only the simplest things, so that the readers would afterwards
B/jrYT$;m understand also the dynamic problems. Also, since in dynamic problems the soils
[O^}rUqq and rocks played a fundamental role, I thought to write a chapter on rocks and soils.
N0=-7wMk(Z Then were expressed several chapters about dynamic plasticity, as propagation of
E fKM*;A elastic–plastic waves in thin bars, the rate influence and the propagation of waves
.Qd}.E G in flexible strings. It is good to remember here that all problems related to dynamic
R{*_1cyW problems, are to be considered using the mechanics of the wave propagation; without
DVObrL)znL the wave propagation mechanics all results concerning constitutive equations,
[J~aAB rate effect, etc. are only informative. Such problems are mentioned however in the
QF\kPk(CtD book. We have presented mainly the different aspects on constitutive equations of
(E!%v`_0 materials, as resulting from dynamic problems. Rate effects are considered in this
|/@0~O(6 way. They have been used by a variety of authors. The same with the mechanics of
xME(B@j flexible strings, presented afterwards. Not very many authors have considered till
mR"uhm}q now the mechanics of deformable cables.
It%T7
X# Therefore I thought to write a very simple book, which can be read by the
$"Af y)Ir students themselves, without any additional help. They can understand what
fO*)LPen.z “plasticity” is after all. Then several other problems have been presented. Not
VR "u* trying to remove the fundamentals, I have thought also to add some additional
z >6.[Z(T problems, which are in fact dynamic, though the inertia effect is disregarded. They
c
Qld$ are the stationary problems, quite often met in many applications. It is question
1'NhjL obviously, about problems involving Bingham bodies, as wire drawing, floating with
y:Z$LmPc< working plug, extrusion, stability of natural inclined plane, etc.
z{%oJ_ Further I have considered various problems of plastic waves, using various
\WWG>OUh.U theories. Also the perforation problems, was presented, using various symmetry
z4 CJn[m9 assumptions, or any other assumption made.
YM i/uy The last chapter is on hypervelocity impact. To keep it simple, I have given
T3=(` only very few information about. Thus I wished to show what hypervelocity is and
F 4Rr2 6M how is it considered now.
);=Q] > Though the book is a very simple one, I wished to ask any author to disregard
sNL+F possible missing of some papers. All literature is certainly incomplete. One has
f[x~)= done today much more than given here. It was impossible for me to mention “all”
V
{p*z authors in this field.
$( S*GF$S N. D. Cristescu
.+OB!'dDK^ cristesc@ufl.edu
