DYNAMIC PLASTICITY
DGR[2C)@N U/hf?T; Copyright © 2007 by World Scientific Publishing Co. Pte. Ltd
Ll "
Kxg (T290a9y> The present book is not simply a new addition of the book Dynamic Plasticity,
]H ze initially published in 1967, a long time ago. Certainly this edition is not only a new
R^v-%mG9 version, containing the essential of the old book and what has been done meantime.
Y^ Of Why again Dynamic Plasticity? Well because very many books published meantime
DC9\ Sp? on the subject are not mentioning the waves which are to be considered in Dynamic
@1+gY4g Plasticity. Also, generally, the plastic waves are slower than the elastic one. Thus,
bl 8zcpdL when considering a simple problem of propagation of waves in thin bars, for any
.<#oLM^
loading at the end, the plastic waves are reached by the elastic ones, and will not
%pikt7,Z~ propagate any more. Only a part of the bar is deforming plastically. Examples of
pr\wI?:k this kind are very few.
54X=58Q I thought that this new version is too restrictive for the today students which
|hx"yy'ux know little of static plasticity, differential equations, dynamic elastic–plastic properties,
gu~JB etc. Therefore, I thought to write a simpler book, containing the main
%A qt0e
concepts of dynamic plasticity, but also something else. Thus I thought that this
`S`,H new version would contain the elementary concepts of static plasticity, etc., which
$N
!l-lu= would be useful to give. Also it would be good to give other problems, not directly
$#z
` R; related to dynamic plasticity. Thus I started with some classical problems on
3 pzp6o2 static plasticity, but only the simplest things, so that the readers would afterwards
E#?Bn5-uBs understand also the dynamic problems. Also, since in dynamic problems the soils
@ Sq
=q=S and rocks played a fundamental role, I thought to write a chapter on rocks and soils.
eo#2n8I>=1 Then were expressed several chapters about dynamic plasticity, as propagation of
; 9n} P@ elastic–plastic waves in thin bars, the rate influence and the propagation of waves
P\j n ht in flexible strings. It is good to remember here that all problems related to dynamic
h>w(Th\H problems, are to be considered using the mechanics of the wave propagation; without
$-J0ou8~ the wave propagation mechanics all results concerning constitutive equations,
m`;dFL7"E rate effect, etc. are only informative. Such problems are mentioned however in the
v&7yqEm}B book. We have presented mainly the different aspects on constitutive equations of
&ikPa ,A materials, as resulting from dynamic problems. Rate effects are considered in this
hg2a,EU\Z way. They have been used by a variety of authors. The same with the mechanics of
g2Hz[C( flexible strings, presented afterwards. Not very many authors have considered till
n j90`O.K now the mechanics of deformable cables.
-0I]Sm;$ Therefore I thought to write a very simple book, which can be read by the
0mt lM( students themselves, without any additional help. They can understand what
teQ <v[W. “plasticity” is after all. Then several other problems have been presented. Not
4N b&(p trying to remove the fundamentals, I have thought also to add some additional
'' P u problems, which are in fact dynamic, though the inertia effect is disregarded. They
c @U\d<{w are the stationary problems, quite often met in many applications. It is question
`G@(Z:]f,t obviously, about problems involving Bingham bodies, as wire drawing, floating with
=c(t;u6m- working plug, extrusion, stability of natural inclined plane, etc.
]'.D@vFGO Further I have considered various problems of plastic waves, using various
4](jV}Hg theories. Also the perforation problems, was presented, using various symmetry
pr=f6~Z-y assumptions, or any other assumption made.
/JqNiqvh The last chapter is on hypervelocity impact. To keep it simple, I have given
**,(>4 j only very few information about. Thus I wished to show what hypervelocity is and
{wp~ how is it considered now.
??]b,f4CNa Though the book is a very simple one, I wished to ask any author to disregard
%%-?~rjI possible missing of some papers. All literature is certainly incomplete. One has
&c AFKYt done today much more than given here. It was impossible for me to mention “all”
E;o
"^[we authors in this field.
R!+_mPb=Q* N. D. Cristescu
BN_I #8r cristesc@ufl.edu
