DYNAMIC PLASTICITY
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mbIz[un Z ^}[CQ&Am The present book is not simply a new addition of the book Dynamic Plasticity,
-uu&{$ initially published in 1967, a long time ago. Certainly this edition is not only a new
{/(.Bpld version, containing the essential of the old book and what has been done meantime.
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1s= Why again Dynamic Plasticity? Well because very many books published meantime
D)bL;h on the subject are not mentioning the waves which are to be considered in Dynamic
W"*2,R[}% Plasticity. Also, generally, the plastic waves are slower than the elastic one. Thus,
xFekSH7[F when considering a simple problem of propagation of waves in thin bars, for any
H2oxD$s loading at the end, the plastic waves are reached by the elastic ones, and will not
^V hl@ propagate any more. Only a part of the bar is deforming plastically. Examples of
QFnp p\K this kind are very few.
CPL,QVO9 I thought that this new version is too restrictive for the today students which
piH0_7qr know little of static plasticity, differential equations, dynamic elastic–plastic properties,
3;FV^V' etc. Therefore, I thought to write a simpler book, containing the main
?E_;[(Mcr concepts of dynamic plasticity, but also something else. Thus I thought that this
Fc8 0HK5R new version would contain the elementary concepts of static plasticity, etc., which
nbB*d@" would be useful to give. Also it would be good to give other problems, not directly
dF09_nw related to dynamic plasticity. Thus I started with some classical problems on
, O/IY static plasticity, but only the simplest things, so that the readers would afterwards
m[(_fOd understand also the dynamic problems. Also, since in dynamic problems the soils
: 5['V#(o and rocks played a fundamental role, I thought to write a chapter on rocks and soils.
6:L2oW 6}{ Then were expressed several chapters about dynamic plasticity, as propagation of
BzzZ.AH~ elastic–plastic waves in thin bars, the rate influence and the propagation of waves
:<s`) in flexible strings. It is good to remember here that all problems related to dynamic
Vhh=GJ problems, are to be considered using the mechanics of the wave propagation; without
{ =\Fc`74 the wave propagation mechanics all results concerning constitutive equations,
kt0xR)gU rate effect, etc. are only informative. Such problems are mentioned however in the
Y+o\?|q-E book. We have presented mainly the different aspects on constitutive equations of
L,.AY?)+7 materials, as resulting from dynamic problems. Rate effects are considered in this
$M j\ 3 way. They have been used by a variety of authors. The same with the mechanics of
SSxz1y flexible strings, presented afterwards. Not very many authors have considered till
zRa2iCi now the mechanics of deformable cables.
V%)T u{L Therefore I thought to write a very simple book, which can be read by the
ar\ K8mj students themselves, without any additional help. They can understand what
TqL+^: cq “plasticity” is after all. Then several other problems have been presented. Not
*7-rm trying to remove the fundamentals, I have thought also to add some additional
ZDAW>H< problems, which are in fact dynamic, though the inertia effect is disregarded. They
hkyO_ns are the stationary problems, quite often met in many applications. It is question
>_xuXEslUz obviously, about problems involving Bingham bodies, as wire drawing, floating with
9J~\.:jH- working plug, extrusion, stability of natural inclined plane, etc.
YF-A8gXS Further I have considered various problems of plastic waves, using various
j:qexhtho theories. Also the perforation problems, was presented, using various symmetry
TpwN2 = assumptions, or any other assumption made.
SB08-G2 The last chapter is on hypervelocity impact. To keep it simple, I have given
7R7+jL , only very few information about. Thus I wished to show what hypervelocity is and
o <iU; 15 how is it considered now.
sa &`CEa Though the book is a very simple one, I wished to ask any author to disregard
*Wvk~ possible missing of some papers. All literature is certainly incomplete. One has
O_ZYm{T[7 done today much more than given here. It was impossible for me to mention “all”
Bu&9J(J1 authors in this field.
5~/EAK` N. D. Cristescu
$=Ns7Sbup cristesc@ufl.edu
