DYNAMIC PLASTICITY
i_@RWka< c%dy$mkqgK Copyright © 2007 by World Scientific Publishing Co. Pte. Ltd
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bqZ @W,Y_8: The present book is not simply a new addition of the book Dynamic Plasticity,
a]k&$ initially published in 1967, a long time ago. Certainly this edition is not only a new
GwycSb1 version, containing the essential of the old book and what has been done meantime.
{3R ax5Ty Why again Dynamic Plasticity? Well because very many books published meantime
M}<=~/k`j on the subject are not mentioning the waves which are to be considered in Dynamic
!L _ SHlU Plasticity. Also, generally, the plastic waves are slower than the elastic one. Thus,
SrtmpQ when considering a simple problem of propagation of waves in thin bars, for any
I6fpXPP). loading at the end, the plastic waves are reached by the elastic ones, and will not
izw}25SW propagate any more. Only a part of the bar is deforming plastically. Examples of
-a[{cu{ this kind are very few.
5zGj,y>u I thought that this new version is too restrictive for the today students which
R;yAqr29 know little of static plasticity, differential equations, dynamic elastic–plastic properties,
buFtLPe etc. Therefore, I thought to write a simpler book, containing the main
E6gEP0b concepts of dynamic plasticity, but also something else. Thus I thought that this
/%c^ i!=f" new version would contain the elementary concepts of static plasticity, etc., which
Y[DKj!v would be useful to give. Also it would be good to give other problems, not directly
+ NY4j-O related to dynamic plasticity. Thus I started with some classical problems on
,+RO 5n static plasticity, but only the simplest things, so that the readers would afterwards
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8JW= understand also the dynamic problems. Also, since in dynamic problems the soils
1L|(:m+ and rocks played a fundamental role, I thought to write a chapter on rocks and soils.
0_EF7`T Then were expressed several chapters about dynamic plasticity, as propagation of
Ed-gYL^< elastic–plastic waves in thin bars, the rate influence and the propagation of waves
f#t^<`7 in flexible strings. It is good to remember here that all problems related to dynamic
2I<T<hFW] problems, are to be considered using the mechanics of the wave propagation; without
a8 1%M the wave propagation mechanics all results concerning constitutive equations,
mI0r,Z*+M rate effect, etc. are only informative. Such problems are mentioned however in the
rifxr4c[X> book. We have presented mainly the different aspects on constitutive equations of
6. jZy~ materials, as resulting from dynamic problems. Rate effects are considered in this
`lhLIQ'j way. They have been used by a variety of authors. The same with the mechanics of
Hn~1x'$ flexible strings, presented afterwards. Not very many authors have considered till
<j#Ey GAV now the mechanics of deformable cables.
6 b|`[t Therefore I thought to write a very simple book, which can be read by the
LA+MX 0* students themselves, without any additional help. They can understand what
E~P 0}' “plasticity” is after all. Then several other problems have been presented. Not
v3"xJN_,[p trying to remove the fundamentals, I have thought also to add some additional
a< EC]-nw problems, which are in fact dynamic, though the inertia effect is disregarded. They
$Da^z[ 8e are the stationary problems, quite often met in many applications. It is question
Uu+C<j&- obviously, about problems involving Bingham bodies, as wire drawing, floating with
"m3Y))a working plug, extrusion, stability of natural inclined plane, etc.
M&F uXG% Further I have considered various problems of plastic waves, using various
r;C \eN theories. Also the perforation problems, was presented, using various symmetry
yd~fC:_ ] assumptions, or any other assumption made.
x(`$D The last chapter is on hypervelocity impact. To keep it simple, I have given
t;]egk only very few information about. Thus I wished to show what hypervelocity is and
Zy%Z]dF how is it considered now.
bM-Rj1#Lo Though the book is a very simple one, I wished to ask any author to disregard
E0Djo'64 possible missing of some papers. All literature is certainly incomplete. One has
{Jc!T:vJ done today much more than given here. It was impossible for me to mention “all”
$yAfs3/%)s authors in this field.
aiH r2x6 N. D. Cristescu
_ XZ=4s cristesc@ufl.edu
