Plasticity - Mathematical Theory and Numerical Analysis y/{fX(aV
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by Weimin Han B. Daya Reddy Nq[uoaT
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Springer 1999 KIf dafRL
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The basis for the modern theory of elastoplasticity was laid in the nineteenthcentury, Gbr=+AT
by Tresca, St. Venant, L´evy, and Bauschinger. Further )e+>w=t
major advances followed in the early part of this century, the chief contributors ^z IW+:
during this period being Prandtl, von Mises, and Reuss. This F=e8 IUr
early phase in the history of elastoplasticity was characterized by the introduction BC#C9|n
and development of the concepts of irreversible behavior, yield +H-6e P
criteria, hardening and perfect plasticity, and of rate or incremental constitutive 9G#n 0&wRJ
equations for the plastic strain. f!uw zHA`?
Greater clarity in the mathematical framework for elastoplasticity theory TH&U
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came with the contributions of Prager, Drucker, and Hill, during the dI(@ZV{
period just after the Second World War. Convexity of yield surfaces, and M*, -zGr
all its ramifications, was a central theme in this phase of the development XB^'K2
of the theory. Fn;SF4KOm
The mathematical community, meanwhile, witnessed a burst of progress Oi'5ytsES
in the theory of partial differential equations and variational inequalities kR-SE5`Jk
from the early 1960s onwards. The timing of this set of developments was O7m(o:t x3
particularly fortuitous for plasticity, given the fairly mature state of the mbTEp*H
subject, and the realization that the natural framework for the study of Lv;^My
initial boundary value problems in elastoplasticity was that of variational /wEhVR`=
inequalities. This confluence of subjects emanating from mechanics and gjwn7_
mathematics resulted in yet further theoretical developments, the outstanding uM IIYS
examples being the articles by Moreau, and the monographs feDlH[$
by Duvaut and J.-L. Lions, and Temam. In this manner the stage was t7Iv?5]N
set for comprehensive investigations of the well-posedness of problems in %KlrSo
elastoplasticity, while the simultaneous rapid growth in interest in numer- ]Kt6^|S$a
ical methods ensured that equal attention was given to issues such as the XK3tgaH
development of solution algorithms, and their convergences. t;}|tgC
The interaction between elastoplasticity and mathematics has spawned l'-Bu(
among many engineering scientists an interest in gaining a better understanding qFCOUl
of the modern mathematical developments in the subject. In the xw,IJ/E$1
same way, given the richness of plasticity in interesting and important .+3g*Dv{&
mathematical problems, many mathematicians, either students or mature yy^q2P
researchers, have developed an interest in understanding the mechanical (ylTp]~mR-
and engineering basis of the subject, and its connections with the mathematical ooj,/IEQ
theory. While there are many textbooks and monographs on plasticity (z{#Eq4
that deal with the mechanics of the subject, they are written mainly (l~AV9!m:
for a readership in the engineering sciences; there does not appear to us .\ULbN3Z
to have existed an extended account of elastoplasticity which would serve d9fC<Tp
these dual needs of both engineering scientists and mathematicians. It is XH 4
our hope that this monograph will go some way towards filling that gap. %+W{iu[|
We present in this work three logically connected aspects of the theory of |^"1{7)
elastic-plastic solids: the constitutive theory, the variational formulations of A5I)^B<(
the related initial boundary value problems, and the numerical analysis of OUPUixz2Z
these problems. These three aspects determine the three parts into which D&&9^t9S
the monograph is divided. .Ni\\
The constitutive theory, which is the subject of Part I, begins with a 1QcNp(MO
motivation grounded in physical experience, whereafter the constitutive o4F2%0gJ
theory of classical elastoplastic media is developed. This theory is then cast s^G.]%iU
in a convex analytic setting, after some salient results from convex analysis jUYWrYJ
have been reviewed. The term “classical” refers in this work to that theory zII|9y
of elastic-plastic material behavior which is based on the notion of convex VK\X&Y3l
yield surfaces, and the normality law. Furthermore, only the small strain, ar!R|zmf
quasi-static theory is treated. Much of what is covered in Part I will be X"|['t
familiar to those working on plasticity, though the greater insights offered Ha0M)0Anv
by exploiting the tools of convex analysis may be new to some researchers. #C74z$
On the other hand, mathematicians unfamiliar with plasticity theory will T= y}y
find in this first part an introduction that is self-contained and accessible. ,GbR!j@6
Part II of the monograph is concerned with the variational problems in n`?aC|P2s
elastoplasticity. Two major problems are identified and treated: the primal Db}j?ik/
problem, of which the displacement and internal variables are the primary ,i?nWlh+
unknowns; and the dual problem, of which the main unknowns are the D[[|")Fn
generalized stresses. _/s$ZCd
Finally, Part III is devoted to a treatment of the approximation of the FF`T\&u
variational problems presented in the previous part. We focus on finite element by1<[$8r
approximations in space, and both semi- and fully discrete problems. lHY+}v0
In addition to deriving error estimates for these approximations, attention `_Zg3_K.dS
is given to the behavior of those solution algorithms that are in common sQHv%]s 0
use. [[Ls_ZL!=
Wherever possible we provide background materials of sufficient depth +aCv&sg
to make this work as self-contained as possible. Thus, Part I contains a In"ZIKaC
Preface ix ok"k*?Ov
review of topics in continuum mechanics, thermodynamics, linear elasticity, O'p9u@kc
and convex analytic setting of elastoplasticity. In Part II we include a 5,lEx1{_
treatment of those topics from functional analysis and function spaces that <SAzxo:I
are relevant to a discussion of the well-posedness of vatriational problems. r4b 6 c
And Part III begins with an overview of the mathematics of finite elements. [\98$BN
In writing this work we have drawn heavily on the results of our joint collaboration
9]([\% )
in the past few years. We have also consulted, and made liberal fM :]&
use of the works of many: we mention in particular the major contributions T?CdZc.
of G. Duvaut and J.-L. Lions, C. Johnson, J.B. Martin, H. ~OYiq}g
Matthies, and J.C. Simo. While we acknowledge this debt with gratitude, x*\Y)9Vgy
the responsibility for any inaccuracies or erroneous interpretations }#RakV4
that might exist in this work, rests with its authors. ,GhS[VJjR
We thank our many friends, colleagues and family members whose interest, )5Q~I,dP
guidance, and encouragement made this work possible. :gv{F} ##
W.H. >UTBO|95y
Iowa City \g&,@'uh
B.D.R. y4
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Cape Town