Plasticity - Mathematical Theory and Numerical Analysis niYz9YX
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by Weimin Han B. Daya Reddy BZJKiiD
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Springer 1999 VR4E
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The basis for the modern theory of elastoplasticity was laid in the nineteenthcentury, m|[\F#+C
by Tresca, St. Venant, L´evy, and Bauschinger. Further tg7C;rJ
major advances followed in the early part of this century, the chief contributors Lf^5Eo/
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during this period being Prandtl, von Mises, and Reuss. This dd\bI_
early phase in the history of elastoplasticity was characterized by the introduction '!wPnYT@D
and development of the concepts of irreversible behavior, yield l5=u3r9WYC
criteria, hardening and perfect plasticity, and of rate or incremental constitutive $/[Gys3"
equations for the plastic strain. 5;FP.{+
Greater clarity in the mathematical framework for elastoplasticity theory ^91sl5c8yD
came with the contributions of Prager, Drucker, and Hill, during the 068WlF cWV
period just after the Second World War. Convexity of yield surfaces, and ^e?$ ]JiA!
all its ramifications, was a central theme in this phase of the development ezcS[r
of the theory. +R
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The mathematical community, meanwhile, witnessed a burst of progress t7|MkX1
in the theory of partial differential equations and variational inequalities j6tP)f^tD
from the early 1960s onwards. The timing of this set of developments was S}.\v<
particularly fortuitous for plasticity, given the fairly mature state of the v#<\:|XAg
subject, and the realization that the natural framework for the study of E\R raPkQT
initial boundary value problems in elastoplasticity was that of variational Cq?',QU6j
inequalities. This confluence of subjects emanating from mechanics and .Lojzx
mathematics resulted in yet further theoretical developments, the outstanding c8#T:HM|`
examples being the articles by Moreau, and the monographs =<[7J]%
by Duvaut and J.-L. Lions, and Temam. In this manner the stage was 6sYV7w,'@
set for comprehensive investigations of the well-posedness of problems in 7o;x (9
elastoplasticity, while the simultaneous rapid growth in interest in numer- CgVh\4,a
ical methods ensured that equal attention was given to issues such as the cs K>iN
development of solution algorithms, and their convergences. Lzh9DYU6
The interaction between elastoplasticity and mathematics has spawned fd?bU|I_2
among many engineering scientists an interest in gaining a better understanding ?_VRfeztw
of the modern mathematical developments in the subject. In the >vQ6V'F
same way, given the richness of plasticity in interesting and important !Z
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mathematical problems, many mathematicians, either students or mature Q&u>7_, Du
researchers, have developed an interest in understanding the mechanical cy1\u2x_`
and engineering basis of the subject, and its connections with the mathematical E x_L!9>!
theory. While there are many textbooks and monographs on plasticity X$Q2m{dR
that deal with the mechanics of the subject, they are written mainly T(Y}V[0+
for a readership in the engineering sciences; there does not appear to us *I:mw8t
to have existed an extended account of elastoplasticity which would serve =LXvlt'Q34
these dual needs of both engineering scientists and mathematicians. It is PqT"jOF]n
our hope that this monograph will go some way towards filling that gap. xik`W!1S
We present in this work three logically connected aspects of the theory of >65
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elastic-plastic solids: the constitutive theory, the variational formulations of `0yb?Nk `:
the related initial boundary value problems, and the numerical analysis of /K_ i8!y
these problems. These three aspects determine the three parts into which 3hc#FmLr2b
the monograph is divided. 'Z\{D*=V8
The constitutive theory, which is the subject of Part I, begins with a "w*@R8v
motivation grounded in physical experience, whereafter the constitutive &}zRH}s;
theory of classical elastoplastic media is developed. This theory is then cast UUl*f!&
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in a convex analytic setting, after some salient results from convex analysis >W8bWQ^fK
have been reviewed. The term “classical” refers in this work to that theory myD{sE2A
of elastic-plastic material behavior which is based on the notion of convex 54=}GnZN
yield surfaces, and the normality law. Furthermore, only the small strain, ;xSRwSNDi(
quasi-static theory is treated. Much of what is covered in Part I will be (-bRj#
familiar to those working on plasticity, though the greater insights offered M|U';2hZN:
by exploiting the tools of convex analysis may be new to some researchers. BiA>QQ
On the other hand, mathematicians unfamiliar with plasticity theory will De;, =BSp
find in this first part an introduction that is self-contained and accessible. mH'\:oN
Part II of the monograph is concerned with the variational problems in LPq2+:JpS
elastoplasticity. Two major problems are identified and treated: the primal j,}4TDWa
problem, of which the displacement and internal variables are the primary 0;vtdM[_
unknowns; and the dual problem, of which the main unknowns are the PT mf
generalized stresses. a|UqeNI{
Finally, Part III is devoted to a treatment of the approximation of the -<O JqB
variational problems presented in the previous part. We focus on finite element >[K0=nA
approximations in space, and both semi- and fully discrete problems. ?#4+r_dP
In addition to deriving error estimates for these approximations, attention -dg} BM
is given to the behavior of those solution algorithms that are in common yHl@_rN
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use. j\!
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Wherever possible we provide background materials of sufficient depth Z%Vr+)!4
to make this work as self-contained as possible. Thus, Part I contains a F\JLbY{x]
Preface ix [d0%.+U
review of topics in continuum mechanics, thermodynamics, linear elasticity, iNt 4>
and convex analytic setting of elastoplasticity. In Part II we include a HH7[tGF
treatment of those topics from functional analysis and function spaces that m6-76ma,hi
are relevant to a discussion of the well-posedness of vatriational problems. 77``8,
And Part III begins with an overview of the mathematics of finite elements. Dft4isyt^
In writing this work we have drawn heavily on the results of our joint collaboration -zprNQW
in the past few years. We have also consulted, and made liberal 6mwvI4)
use of the works of many: we mention in particular the major contributions _~PO
of G. Duvaut and J.-L. Lions, C. Johnson, J.B. Martin, H. #`vVgGZ&
Matthies, and J.C. Simo. While we acknowledge this debt with gratitude, >Z}@7$(7!~
the responsibility for any inaccuracies or erroneous interpretations +hpSxdAz4
that might exist in this work, rests with its authors. _ ~|Q4AJ
We thank our many friends, colleagues and family members whose interest, g+.0c=G(
guidance, and encouragement made this work possible. Cgo9rC~]
W.H. j13riI3A
Iowa City (JWv *p
B.D.R. 'X54dXS?l
Cape Town