Automatic feedback control for one class of contact piezoelectric problems
In this paper we investigate the dynamics of solutions of the second order evolution inclusion with discontinuous interaction function which can be represented as the difference of subdifferentials. This case is actual for feedback automatic control problems. In particular, we concider mathematical...
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Навчально-науковий комплекс "Інститут прикладного системного аналізу" НТУУ "КПІ" МОН та НАН України
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irk-123456789-854602015-09-09T17:30:01Z Automatic feedback control for one class of contact piezoelectric problems Zgurovsky, M.Z. Kasyanov, P.O. Paliichuk, L.S. Математичні методи, моделі, проблеми і технології дослідження складних систем In this paper we investigate the dynamics of solutions of the second order evolution inclusion with discontinuous interaction function which can be represented as the difference of subdifferentials. This case is actual for feedback automatic control problems. In particular, we concider mathematical model of contact piezoelectric process between a piezoelectric body and a foundation and for this problem investigate the long-term behavior of state function. We deduce a priory estimates for weak solutions of studied problem in the phase spase. The theorem on the existence of a global attractor for multi-valued semiflow generated by weak solutions of the problem and the structural properties of the limit sets is prooved. The main results of the paper were applied to the investigated piezoelectric problem. Досліджено динаміку розв’язків еволюційного включення другого порядку з розривною функцією взаємодії, яка може бути представлена у вигляді різниці субдиференціалів. Цей випадок є актуальним для задач автоматичного управління зі зворотнім зв’язком. Розглянуто математичну модель контактного п’єзоелектричного процесу між п’єзоелектричним тілом та опорою, і для неї досліджено довгострокову поведінку функції стану. Введено апріорні оцінки для слабких розв’язків даної задачі в фазовому просторі. Доведено теорему про існування глобального атрактора для багатозначного напівпотоку, породженого слабкими розв’язками задачі, та про структурні властивості граничних множин. Основні результати було застосовано до досліджуваної п’єзоелектричної задачі. Исследована динамика решений эволюционного включения второго порядка с разрывной функцией взаимодействия, которая может быть представлена в виде разности субдифференциалов. Данный случай является актуальным для задач автоматического управления с обратной связью. Рассмотрена математическая модель контактного пьезоэлектрического процесса между пьезоэлектрическим телом и опорой, и для нее исследовано долгосрочное поведение функции состояния. Выведены априорные оценки для слабых решений рассматриваемой задачи в фазовом пространстве. Доказана теорема о существовании глобального аттрактора для многозначного полупотока, порожденного слабыми решениями задачи, и о структурных свойствах предельных множеств. Основные результаты были применены к исследуемой пьезоэлектрической задаче. 2014 Article Automatic feedback control for one class of contact piezoelectric problems / М.Z. Zgurovsky, P.О. Kasyanov, L.S. Paliichuk // Системні дослідження та інформаційні технології. — 2014. — № 1. — С. 56-68. — Бібліогр.: 10 назв. — англ. 1681–6048 http://dspace.nbuv.gov.ua/handle/123456789/85460 517.9 en Системні дослідження та інформаційні технології Навчально-науковий комплекс "Інститут прикладного системного аналізу" НТУУ "КПІ" МОН та НАН України |
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Математичні методи, моделі, проблеми і технології дослідження складних систем Математичні методи, моделі, проблеми і технології дослідження складних систем |
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Математичні методи, моделі, проблеми і технології дослідження складних систем Математичні методи, моделі, проблеми і технології дослідження складних систем Zgurovsky, M.Z. Kasyanov, P.O. Paliichuk, L.S. Automatic feedback control for one class of contact piezoelectric problems Системні дослідження та інформаційні технології |
description |
In this paper we investigate the dynamics of solutions of the second order evolution inclusion with discontinuous interaction function which can be represented as the difference of subdifferentials. This case is actual for feedback automatic control problems. In particular, we concider mathematical model of contact piezoelectric process between a piezoelectric body and a foundation and for this problem investigate the long-term behavior of state function. We deduce a priory estimates for weak solutions of studied problem in the phase spase. The theorem on the existence of a global attractor for multi-valued semiflow generated by weak solutions of the problem and the structural properties of the limit sets is prooved. The main results of the paper were applied to the investigated piezoelectric problem. |
format |
Article |
author |
Zgurovsky, M.Z. Kasyanov, P.O. Paliichuk, L.S. |
author_facet |
Zgurovsky, M.Z. Kasyanov, P.O. Paliichuk, L.S. |
author_sort |
Zgurovsky, M.Z. |
title |
Automatic feedback control for one class of contact piezoelectric problems |
title_short |
Automatic feedback control for one class of contact piezoelectric problems |
title_full |
Automatic feedback control for one class of contact piezoelectric problems |
title_fullStr |
Automatic feedback control for one class of contact piezoelectric problems |
title_full_unstemmed |
Automatic feedback control for one class of contact piezoelectric problems |
title_sort |
automatic feedback control for one class of contact piezoelectric problems |
publisher |
Навчально-науковий комплекс "Інститут прикладного системного аналізу" НТУУ "КПІ" МОН та НАН України |
publishDate |
2014 |
topic_facet |
Математичні методи, моделі, проблеми і технології дослідження складних систем |
url |
http://dspace.nbuv.gov.ua/handle/123456789/85460 |
citation_txt |
Automatic feedback control for one class of contact piezoelectric problems / М.Z. Zgurovsky, P.О. Kasyanov, L.S. Paliichuk // Системні дослідження та інформаційні технології. — 2014. — № 1. — С. 56-68. — Бібліогр.: 10 назв. — англ. |
series |
Системні дослідження та інформаційні технології |
work_keys_str_mv |
AT zgurovskymz automaticfeedbackcontrolforoneclassofcontactpiezoelectricproblems AT kasyanovpo automaticfeedbackcontrolforoneclassofcontactpiezoelectricproblems AT paliichukls automaticfeedbackcontrolforoneclassofcontactpiezoelectricproblems |
first_indexed |
2025-07-06T12:39:42Z |
last_indexed |
2025-07-06T12:39:42Z |
_version_ |
1836901290902290432 |
fulltext |
© M.Z. Zgurovsky, P.O. Kasyanov, L.S. Paliichuk, 2014
56 ISSN 1681–6048 System Research & Information Technologies, 2014, № 1
TIДC
МАТЕМАТИЧНІ МЕТОДИ, МОДЕЛІ,
ПРОБЛЕМИ І ТЕХНОЛОГІЇ ДОСЛІДЖЕННЯ
СКЛАДНИХ СИСТЕМ
УДК 517.9
AUTOMATIC FEEDBACK CONTROL FOR ONE CLASS
OF CONTACT PIEZOELECTRIC PROBLEMS
M.Z. ZGUROVSKY, P.O. KASYANOV, L.S. PALIICHUK
In this paper we investigate the dynamics of solutions of the second order evolution
inclusion with discontinuous interaction function which can be represented as the
difference of subdifferentials. This case is actual for feedback automatic control
problems. In particular, we concider mathematical model of contact piezoelectric
process between a piezoelectric body and a foundation and for this problem
investigate the long-term behavior of state function. We deduce a priory estimates
for weak solutions of studied problem in the phase spase. The theorem on the
existence of a global attractor for multi-valued semiflow generated by weak
solutions of the problem and the structural properties of the limit sets is prooved.
The main results of the paper were applied to the investigated piezoelectric problem.
INTRODUCTION AND PROBLEM FORMULATION
Let us consider a mathematical model which describes the contact between
a piezoelectric body and a foundation. We formulate this problem as in [1].
Let dR be a d -dimensional real linear space and dS be the linear space of
second order symmetric tensors on dR with the inner product ijij
ij
τστσ ∑=:
and the corresponding norm τττ :2 =dS , ijσ , .dij S∈τ
Let us consider a plane electro-elastic material which in its undeformed state
occupies an open bounded domain ,Ω dR⊂ .2=d This domain as a result of
volume forces and boundary friction can contact with rigid or elastic support. Let
the boundary of piezoelectric body Ω be Lipschitz continuous. Assume that the
boundary Γ, on the one hand, consists of two disjoint measurable parts DΓ and
NΓ , 0)Γ( >Dm and, on the other hand, consists of two disjoint measurable parts
aΓ and bΓ , 0)Γ( >am (Figure). Suppose that the body is clamped on ,ΓD so
the displacement field ,: dQu R→ ),,( txuu = where ),0(Ω ∞+×=Q , vanishes
there. Moreover, a surface traction of density g act on ,ΓN and the electric
potential R→Ω:ϕ vanishes on .Γa The body Ω is lying on “support” medium,
which introduce frictional effects. The interaction between the body and the
Automatic feedback control for one class of contact piezoelectric problems
Системні дослідження та інформаційні технології, 2014, № 1 57
support is described, due to the adhesion or skin friction, by a nonmonotone
possibly multivalued law between the
bonding forces and the corresponding
displacements.
The body forces of density f
consist of force ,ef which is prescribed
external loading and force sf which is
the reaction of constrains introducing the
skin effects, i.e. se fff += . Here sf is
a possibly multivalued function of the
displacement u .
To describe the contact between
a piezoelectric body Ω and a foundation
let us consider the basic piezoelectric equations: equation of motion, equilibrium
equation, strain-displacement equation, equation of electric field-potential and
other constitutive relations (see [1] and references therein).
We suppose that the process is dynamic. Let us set the constant mass density
.1=ρ Then we have the equation of motion for the stress field and the
equilibrium equation for the electric displacement field respectively:
, in Div Qufu ttt γσ −=− (1)
, in 0div QD =
where (Ω)L∞γ ∈ is nonnegative function of viscosity; ,: dQ S→σ ( )ijσ σ= is
stress tensor; ,Ω: dD R→ ),( iDD = , 1, 2i j = is the electric displacement
field; )(Div , jijσσ = is the divergence operator for tensor valued functions;
)(div , iiDD = is the divergence operator for vector valued. Equation (1) regulates
the change in time of the mechanical state of the piezoelectric body.
The stress-charge form of piezoelectric constitutive relations describes the
behavior of the material and are following:
, in )()( T QEu ϕεσ PA −=
, in )()( QEuD ϕε BP +=
where dd SS →×Ω:A is a linear elasticity operator with the elasticity tensor
,)( ijklaa = 2,1,,, =lkji ; dd RS →×Ω:P is a linear piezoelectric operator
represented by the piezoelectric coefficients ),( ijkpp = ;2,1,, =kji
dd SR →×Ω:TP is transpose to P operator represented by
)()( TT
kijijk pp ==P , ,2,1,, =kji dd RR →×Ω:B is a linear electric
permittivity operator with the dielectric constants ),( ijββ = ;2,1, =ji
)),(()( uu ijεε = , 1, 2i j = is the linear strain tensor; )),(()( ϕϕ iEE = the electric
vector field.
Figure. Partition of Γ
M.Z. Zgurovsky, P.O. Kasyanov, L.S. Paliichuk
ISSN 1681–6048 System Research & Information Technologies, 2014, № 1 58
The elastic strain-displacement and electric field-potential relations are
given by
, in ))((2/1)( T Quuu ∇+∇=ε
. in )( QE ϕϕ −∇=
We consider the reaction-displacement law of the form:
, in )),(,()),(,(),( 21 QtxuxGtxuxGtxf s ∂−∂∈−
where RR →× d
iG Ω: , 2,1=i are measurable in ( , )x u , convex in u for a.e.
Ω∈x functionals; ),,( ⋅∂ xGi 2,1=i are their subdifferentials [2, Chapter 2].
Let 0u be the initial displacement and 1u be the initial velocity. The
classical formulation of the mechanical model can be stated as follows: find
a displacement field u on dR×Ω and an electric potential ϕ on R×Ω such that:
, in Div Quffu tsett γσ −+=−
, in 0div QD =
,in )()( T QEu ϕεσ PA −=
, in )()( QEuD ϕε BP +=
,in )),(,()),(,(),( 21 QtxuxGtxuxGtxfs ∂−∂∈− (2)
),,0( on Γ ),,0( on Γ0 TgnTu ND ×=×=
),,0( on Γ0 ),,0( on Γ0 TDnT ba ×=×=ϕ
,)0( ,)0( 10 uuuu t ==
where n denotes the outward unit normal to Γ.
We now turn to the variational formulation of Problem (2). Let us
consider the space 0:);Ω({ 1 =∈= vHvV dR on ).;Ω(}Γ 1 d
D H R⊂ Let =H
),;Ω(2 dL R= );Ω( dR=H be a Hilbert spaces equipped with the inner products
uvdxvu H ∫=〉〈
Ω
, and dxτστσ :,
Ω
∫=〉〈 H respectively. Then ),,( *VHV be an
evolution triple of spaces. Then H〉〈=〉〈 )(),(, vuvu V εε , H)(vv V ε= , Vvu ∈,
is the inner product and the corresponding norm on V . Therefore ),( VV ⋅ is
Hilbert space.
Assume that ,2,1 ,Ω: =→× iG d
i RR satisfies standard Carathéodory’s
conditions, and there exist )Ω(1
)( Lc i ∈ and ,0)( >iα and that ≤d
id
R
|||| )(
duxc ii
R
||||)( )()( α+≤ for a.e. Ω∈x and any du R∈ , .),()( uxGd i
i ∂∈
Moreover, )2(α is sufficiently small.
Let us set the following hypotheses for the constitutive tensors:
Automatic feedback control for one class of contact piezoelectric problems
Системні дослідження та інформаційні технології, 2014, № 1 59
(i) ),( ijklaa = ),Ω(∞Laijkl ∈ klijijkl aa = , jiklijkl aa = , ijlkijkl aa = ,
ijijklijijkl xa τατττ ≥)( for a.e. Ω∈x , d
ij +∈=∀ S)(ττ , ;0>α
(ii) ),( ijkpp = ;)Ω(∞Lpijk ∈
(iii) ),( ijββ = )Ω(∞ββ Ljiij ∈= , 2||||)( dmx jiij R
ζζζβ β≥ for a.e. Ω∈x ,
d
i R∈=∀ )(ζζ , .0>βm
Without loss of generality let us consider 0≡g and 0≡ef . Following [1],
we present Problem ( 2 ) in the generalized formulation:
( )
⎪⎩
⎪
⎨
⎧
==
∋∂−∂+++
,)0( ,)0(
, for a.e. ,0))(()()()()(
10
_
21
uuuu
ttuJtuJtAutButu
t
ttt (3)
where ;: *VHB → ;: *VVA → RHJi →: , 2,1=i are locally Lipschitz
functionals, dxxuxGuJ ii ))(,(:)(
Ω
∫= , .2,1=i iJ∂ is the Clarke subdifferential
for )(⋅iJ , 2,1=i ; );;( *VHV is evolution triple.
Note that the parameters of Problem (3) satisfy following assumptions [1]:
• Assumtion :)(B HHB →: be a linear symmetric such that there exists
0>β such that 2),( HH vvBv β= ;Hv∈∀
• Assumtion : )(A V is a Hilbert space; *:A V V→ be a linear,
symmetric and there exists 0Ac > such that 2,
VAV vcvAv ≥〉〈 ;Vv∈∀
• Assumtion :)(J RHJi →: , 2,1=i be the functions such that
(i) )(⋅iJ , 2,1=i are locally Lipschitz and regular (see Clarke [2]), i.e.:
- for any ,, Hvx ∈ the usual one-sided directional derivative
t
xJtvxJ
vxJ ii
ti
)()(
lim);(
0
−+
=′
→
, 2,1=i , exists,
- for all ,, Hvx ∈ ,);();( vxJvxJ ii
o=′ where =);( vxJi
o
t
yJtvyJ ii
txy
)()(
lim
0 ,
−+
=
→→
, ;2,1=i
(ii) for 2,1=i there exists 0>ic such that
; ),( ),1( HvvJlvcl iHiH ∈∀∂∈∀+≤
(iii) there exists 02 >c such that
, ),( ,),( 22
2 HvvJlcvvl HH ∈∀∂∈∀+≤ λ
where ( )( ) { | ( , ) ; }i H iJ u p H p w J u w w H∂ = ∈ ≤ ∀ ∈o denotes the Clarke
subdifferentials of ,)(⋅iJ 2,1=i at a point Hu∈ (see Clarke [2] for details);
),0( 1λλ ∈ , 01 >λ : 2
1
2
HVA vvc λ≥ .Vv∈∀
M.Z. Zgurovsky, P.O. Kasyanov, L.S. Paliichuk
ISSN 1681–6048 System Research & Information Technologies, 2014, № 1 60
We define Hilbert space X V H= × as the phase space for Problem (3). Let
.∞+<<<− Tτ∞
Definition. Let . ∞+<<<∞− Tτ The function ];,[))(),(( XTLuu T
t τ∞∈⋅⋅
is called a weak solution for Problem (3) on ],[ Tτ if there exist );,(2 HTLli τ∈ ,
,2,1=i ))(()( tuJtl ii ∂∈ for a.e. ( , )t Tτ∈ such that ,V∈∀ψ :),(0 TC τη ∞∈∀
+− ∫ dtttu tHt
T
)()),(( ηψ
τ
[ ] .0)()),(()),(()),(()),(( 21 =−+++ ∫ dtttltltutu HHHHt
T
ηψψψψ
τ
Theorem 1.4 from [1] provides the existance of a weak solution of
Problem (3) on ],[ Tτ with initial data
buau t == )( ,)( ττ (4)
for any ,Va∈ .Hb∈
In the non-autonomous case the abstract existence results for such problem
with nonmonotone skin effects are presented in [1]. The long-time behavior of all
weak solutions for this problem with continuous interaction function is
investigated by Ball in [3]. The solution dynamics for autonomous model when
02 ≡J is studied in [4], [5]. The particular scalar situation is considered in [6].
Here we consider the case of multidimensional laws with discontinuous
interaction function which can be represented as the difference of subdifferentials,
that is actual for feedback automatic control problems. The main purpose of this
paper is to investigate the long-term behavior of state function, to study the
structural properties of the limit sets and to deduce sufficient conditions that
direct the system to the desired asymptotic level.
PROPERTIES OF SOLUTIONS
We consider a class of functions ).];,([ XTCW T ττ = To simplify our conclusions
from Assumptions ( )A , ( )B we suppose that
,),(),( ,, ,,),( 2
HHVVVV vBuvuvAuvvAuvu =〉〈=〉〈= β
., ),(2 VvuvBvv HH ∈∀=β (5)
Let us set ),()()( 21 uJuJuJ −= .Hu∈ Lebourgue’s mean value theorem
[2, Chapter 2] yields the existence of constants 3 4, 0c c > and :),0( 1λμ∈
.
2
)( ),1(|)(| 4
22
3 HucuuJucuJ HH ∈∀−−≥+≤
μ (6)
According to [7, Lemma 4.1, p. 78], [7, Lemma 3.1, p. 71] and [1,
Theorem 1.4] the following existence result holds.
Automatic feedback control for one class of contact piezoelectric problems
Системні дослідження та інформаційні технології, 2014, № 1 61
Lemma 1. For any ,T<τ ,Va∈ Hb∈ Cauchy problem (3), (4) has
a weak solution ).;,(),( XTLuu T
t τ∞∈ Moreover, each weak solution T
tuu ),( of
Cauchy problem (3), (4) on the interval ],[ Tτ belongs to the space )];,([ XTC τ
and ).;,( *
2 VTLutt τ∈
Let us consider the next denotations: Xba T ∈=∀ ),(τϕ we consider
T
tT uu ))(),({()(, ⋅⋅=ττ ϕD | T
tuu ),( is a weak solution of (3) on ],[ Tτ , ,)( au =τ
})( but =τ . Lemma 1 implies that .)];,([)(,
T
T WXTC τττ τϕ =⊂D
Note that translation and concatenation of weak solutions are also the weak
solutions.
Lemma 2. If ∞+<<< Tτ0 , ,X∈τϕ ),()( , ττ ϕϕ TD∈⋅ then =⋅)(ψ
)()( , ττ ϕϕ sTss −−∈+⋅= D s∀ . If ,Tt <<τ ,X∈τϕ )()( , ττ ϕϕ tD∈⋅ and
)()( , τϕψ TtD∈⋅ , then
⎩
⎨
⎧
∈
∈
=
],[),(
],,[),(
)(
Ttss
tss
s
ψ
τϕ
θ belongs to ).(, ττ ϕTD
Proof. The proof is trivial.
Let Xba T ∈= ),(ϕ and
).()(
2
1)( 21
2 aJaJX −+= ϕϕV (7)
Then we have the next lemma.
Lemma 3. Let ,∞+<<<∞− Tτ ,X∈τϕ ).())(),(()( , ττ ϕϕ T
T
tuu D∈⋅⋅=⋅
Then RT →],[: τϕoV is absolutely continuous function, and for a.e. ),( Tt τ∈
2)())(( Ht tut
dt
d βϕ −=V .
Proof. Let ∞+<<<∞− Tτ , TT
t Wuu τϕ ∈⋅⋅=⋅ ))(),(()( be an arbitrary weak
solution of (3) on ).,( Tτ As ),;,())(( 2 HTLuJ i τ⊂⋅∂ 1, 2i = then from [7,
Lemma 4.1, p. 78] and [7, Lemma 3.1, p. 71] we get that the function
22 )()( VHt tutut +→ is absolutely continuous, and for a.e. :),( Tt τ∈
[ ] =+=+ HtttVHt tutAutututu
dt
d ))(),()(()()(
2
1 22
,))(),(())(),(()( 21
2
HtHtHt tutltutltu +−−= β (8)
where ))(()( tuJtl ii ∂∈ , 2,1=i for a.e. ),( Tt τ∈ and ).;,()( 2 HTLli τ∈⋅
As )];,([)( 1 HTCu τ∈⋅ and RHJi →: , 2,1=i are regular and locally
Lipschitz, due to [5, Lemma 2.16] we obtain that for a.e. ),( Tt τ∈ there exist
),)(( tuJ
dt
d
i o .2,1=i Moreover, ),,())(( 1 TLuJ
dt
d
i τ∈⋅o 2,1=i and for a.e.
M.Z. Zgurovsky, P.O. Kasyanov, L.S. Paliichuk
ISSN 1681–6048 System Research & Information Technologies, 2014, № 1 62
,),( Tt τ∈ )),(( tuJp i∂∈∀ ,2,1=i Hti tuptuJ
dt
d ))(,())(( =o , .2,1=i In
particular, for a.e. ),( Tt τ∈ ,))(),(())(( Htii tutltuJ
dt
d
=o .2,1=i Taking into
account (8) we finally obtain the necessary statement.
The lemma is proved.
Lemma 4. Let 0>T . Then any weak solution of Problem (3) on ],0[ T can
be extended to a global one defined on ),0[ ∞+ . For any X∈0ϕ and )( 0ϕϕ D∈
the next inequality holds :0 >∀t
,
)(2
)0(
2
)(
1
1432
1
312
μλ
λ
ϕ
μλ
λ
ϕ
−
+
+
−
+
≤
ccc
t XX (9)
where for an arbitrary X∈0ϕ let )( 0ϕD be the set of all weak solutions (defined
on ),0[ ∞+ ) of problem (3) with initial data .)0( 0ϕϕ =
Proof. The statement of this lemma follows from Lemmas 1–3, conditions
(5), (6) and from the next estimates:
),())(),(()( , , , τττ ϕϕϕτ T
T
tuuXT D∈⋅⋅=⋅∀∈∀<∀
],[ Tt τ∈∀ 22
1
3
3 )()(
2
12 HtV uu
c
c ττ
λ
+⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
++ =≥≥ ))((2))((2 tϕτϕ VV
4
22
1
22 2)()(1))((2)()( ctututuJtutu HtVHtV −+⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
−≥++=
λ
μ .
The lemma is proved.
Now let us provide the continuity property for the weak solutions of the
main problem in the weak topologies of the phase and the extended phase spaces.
Theorem 1. Let ,T<τ T
nn Wτϕ ⊂⋅ ≥1)}({ be an arbitrary sequence of weak
solutions of (3) on ],[ Tτ such that τϕτϕ →)(n weakly in ,X ∞+→n , and let
],[}{ 1 Tt nn τ⊂≥ be a sequence such that ,0ttn → ∞+→n . Then there exists
)(, ττ ϕϕ TD∈ such that up to a subsequence )()( 0ttnn ϕϕ → weakly in ,X
∞+→n .
Proof. Let ,Tτ < T
nnnn Wuu τϕ ⊂⋅′⋅=⋅ ≥1))}(),(()({ be an arbitrary sequence
of the weak solutions of (3) on ],[ Tτ , and ],[}{ 1 Tt nn τ⊂≥ such that
. , , in weakly )( 0 ∞+→→→ nttX nn τϕτϕ (10)
According to Lemma 4 we have that 1)}({ ≥⋅ nnϕ is bounded on
).;,( XTLW T ττ ∞⊂ Therefore there exists a subsequence 11 )}({)}({ ≥≥ ⋅⊂⋅ nnknk
ϕϕ
such that
Automatic feedback control for one class of contact piezoelectric problems
Системні дослідження та інформаційні технології, 2014, № 1 63
,,);,(instarweakly
,,);,(instarweakly
,,),(a.e.forin)()(
,,],[a.e.forin)()(
,,);,(in
,,);,(instarweakly
,,);,(instarweakly
,,);,(instarweakly
,,);,(instarweakly
*
2
2
*
2
,
*
∞+→→
∞+→′→′
∞+→∈′→′
∞+→∈→
∞+→→
∞+→→
∞+→′′→′′
∞+→′→′
∞+→→
∞
∞
∞
∞
kVTLAuAu
kHTLuBuB
kTtVtutu
kTtHtutu
kHTLuu
kHTLll
kVTLuu
kHTLuu
kVTLuu
kn
kn
kn
kn
kn
iikn
kn
kn
kn
τ
τ
τ
τ
τ
τ
τ
τ
τ
(11)
where );,(2, HTLl in τ∈ be such that
,)()()()()( 2,1, FtAutltltuBtu nnnnn =+−+′+′′
)),(()(, tujtl niin ∂∈ .2,1 ,1 ),,( for a.e. =≥∈ inTt τ
Since ij∂ , 2,1=i is demiclosed, the following inclusion holds:
))(()( ⋅∂∈⋅ ujl ii , 2,1=i , where .)(),(: ,
T
Tt Wuu τττ ϕϕ ⊂∈= D
For a fixed Vh∈ formula (11) implies that the sequence of real functions
)),(( hu
kn ⋅ is uniformly bounded and equicontinuous one. According to (9), (11)
and the density of V in H we obtain that )()( 0tutu
kk nn ′→′ weakly in H and
)()( 0tutu
kk nn → weakly in V as .∞+→k
The theorem is proved.
Theorem 2. Let ,Tτ < T
nn Wτϕ ⊂⋅ ≥1)}({ be an arbitrary sequence of weak
solutions of (3) on ],[ Tτ such that τϕτϕ →)(n strongly in ,X ∞+→n , then up
to a subsequence )()( ⋅→⋅ ϕϕn in ),];,([ XTC τ ∞+→n .
Proof. The proof follows from [4, Theorem 2] and Lemma 3.
MAIN RESULTS
Now let us examine the long-time behavior of all weak solutions of the main
problem as time .∞+→t For this purpose let us define the m-semiflow G as
.0 )},()(| )({),( 00 ≥∈⋅= ttt ξξξξ DG (12)
Denote the set of all nonempty (nonempty bounded) subsets of X by )(XP
))(( Xβ . Note that the multivalued map )(: XPXR →×+G is a strict
m-semiflow, i.e. (see Lemma 2): dI),0( =⋅G (the identity map),
)),(,(),( xstxst GGG =+ +∈∈∀ RstXx ,, . Further G∈ϕ will mean that
)( 0ξϕ D∈ for some .0 X∈ξ
M.Z. Zgurovsky, P.O. Kasyanov, L.S. Paliichuk
ISSN 1681–6048 System Research & Information Technologies, 2014, № 1 64
We recall, that the m-semiflow G is asymptotically compact if for any
sequence G∈≥1}{ nnϕ 1)}0({ ≥nnϕ is bounded, and for any sequence :}{ 1≥nnt
∞+→nt as ∞→n , the sequence 1)}({ ≥nnn tϕ has a convergent subsequence.
Let us consider a family )( 00
uXu DK ∈+ = U of all weak solutions of
inclusion (3) defined on ),0[ ∞+ . Note that +K is translation invariant one, i.e.
+∈⋅∀ K)(u , 0≥∀h +∈⋅ K)(hu , where ,)()( shusuh += 0≥s . On +K we set
the translation semigroup 0)}({ ≥hhT , )()()( ⋅=⋅ huuhT , ,0≥h +∈Ku . In view
of the translation invariance of +K we conclude that ++ ⊂ KK)(hT as 0≥h . On
+K we consider a topology induced from the Fréchet space .);(loc XRC + Note
that
0 );( in )()( loc >∀⇔⋅→⋅ + MXRCffn
),];,0([ in )(Π)(Π XMCff MnM ⋅→⋅
where MΠ is the restriction operator to the interval ],0[ M [8, p.179]. We denote
the restriction operator to ),0[ ∞+ by .Π+
Let us consider autonomous inclusion (3) on the entire time axis. Similarly
to the space );(loc XRC + the space );(loc XRC is endowed with the topology of
local uniform convergence on each interval RMM ⊂− ],[ (cf. [8, p. 180]).
A function );();(loc XRLXRCu ∞∩∈ is said to be a complete trajectory of
inclusion (3) if Rh∈∀ ++ ∈⋅ K)(Π hu [8, p. 180].
Let K be a family of all complete trajectories of inclusion (3). Note that
Rh∈∀ , K∈⋅∀ )(u K∈⋅)(hu . We say that the complete trajectory K∈ϕ is
stationary if zt =)(ϕ for all t R∈ for some .Xz∈
Following [9, p. 486] we denote the set of the rest points of G by ).(GZ We
remark that }.0)()()( , | ),0{()(
_
21
_
∋∂−∂+∈= uJuJuAVuuZ G Assumptions )(A
and )(J provide that the set )(GZ is bounded in .X Lemma 3 implies the
existence of a Lyapunov type function [9, p.486] for m-semiflow G.
We consider construction presented in Ball [9], Melnik and Valero [10]. We
recall that the set A is said to be a global attractor for G if: (i) ),,( AGA t⊂
;0≥∀t (ii) A is attracting set, i.e.
),( , ,0)),,((dist XCtCt β∈∀∞+→→AG (13)
where XEeDd edED −= ∈∈ infsup),(dist is the Hausdorff semidistance; (iii) for
any closed set HY ⊂ satisfying (13), we have .Y⊆A The global attractor is
invariant if ,),( AGA t= .0≥∀t
Provide the main result of this paper.
Automatic feedback control for one class of contact piezoelectric problems
Системні дослідження та інформаційні технології, 2014, № 1 65
Theorem 3. The m-semiflow G has the invariant compact in the phase
space X global attractor A . For each K∈ψ the limit sets
ztXz j →∈= )( |{)( ψψα for some sequence },∞−→jt
ztXz j →∈= )( |{)( ψψω for some sequence }∞+→jt
are connected subsets of )(GZ on which V is constant. If )(GZ is totally
disconnected (in particular, if )(GZ is countable), the limits ),(lim tz
t
ψ
∞−→
− =
)(lim tz
t
ψ
∞+→
+ = exist and −z , +z are the rest points; furthermore, )(tϕ tends to
a rest point as ∞+→t for every +∈Kϕ .
Proof. According to Theorems 1, 2 and [3, Theorem 2.7] we need to provide
that m-semiflow G is asymptotically compact.
Let ),,( nnn vtG∈ξ )(XCvn β∈∈ , 1≥n , ,∞+→nt .∞+→n Let us
check the precompactness of 1}{ ≥nnξ in .X In order to do that without loss of the
generality it is sufficiently to extract a convergent in X subsequence from
1}{ ≥nnξ . From Lemma 4 we obtain that there exist such 1}{ ≥knk
ξ and X∈ξ that
ξξ →
kn weakly in ,X XXn a
k
ξξ ≥→ , .∞+→k Show that Xa ξ≤ .
Let us fix an arbitrary .00 >T Then for rather big 1≥k
)),(,(),( 00 kkkk nnnn vTtTvt −⊂ GGG . Hence, ),,( 0 kk nn T βξ G∈ where ∈
knβ
),( 0 kk nn vTt −∈ G and ∞+<
≥ Xn
k
k
β
1
sup (see Lemma 4). From Theorem 1 for
some 1 1{ , } { , }
j j k kk k j n n kξ β ξ β≥ ≥⊂ , XT ∈
0
β we obtain:
. , in weakly ),,(
000 ∞+→→∈ jXT TkT j
βββξ G (14)
From the definition of G we set: 1≥∀ j ,))(),(( 00
T
jjk TuTu
j
′=ξ
,))0(),0(( T
jjk uu
j
′=β ,))(),(( 0000
TTuTu ′=ξ ,))0(),0(( 000
T
T uu ′=β where
),];,0([),( 0 XTCuu T
jjj ∈′=ϕ ),;,0( *
02 VTLu j ∈′ ),;,0( 0 HTLl j ∞∈
)),(()( ,0)()()()()( ,
_
2,1, tuJtltltltAutuBtu jiijjjjjj ∂∈=−++′+′′
),0(a.e. for 2,1 0Tti ∈= .
Let for each ],0[ 0Tt ∈
)).(),((
2
))(())(()(
2
1:))(( 21
2
tututuJtuJttI jjjjXjj ′+−+=
βϕϕ
Then, in virtue of [5, Lemma 2.16], [7, Lemma 4.1, p.78] and [7, Lemma
3.1, p.71], )),(())((
))((
ttI
dt
tdI
jj
j ϕβϕβ
ϕ
H+−= for a.e. ,),0( 0Tt ∈ where
M.Z. Zgurovsky, P.O. Kasyanov, L.S. Paliichuk
ISSN 1681–6048 System Research & Information Technologies, 2014, № 1 66
)).(),((
2
1))(())(),((
2
1))(())(( 2,21,1 tutltuJtutltuJt jjjjjjj +−−=ϕH
From (9), (14) we have that there exists :0
_
>R 0≥∀ j ],0[ 0Tt∈∀
.)()(
_
222
Rtutu
VjHj ≤+′ Moreover,
, ),;,0( in weakly 020 ∞+→→ jVTLuu j
, ),;,0( in weakly 020 ∞+→′→′ jHTLuu j
, ),;,0( in 020 ∞+→→ jHTLuu j
, ),;,0( in weakly 02, ∞+→→ jHTLll iij (15)
, ),;,0( in weakly *
020 ∞+→′′→′′ jVTLuu j
. , in )()( ],0[ 00 ∞+→→∈∀ jHtutuTt j
For any 0≥j and ],0[ 0Tt ∈
,))(())0(())(( )(
0
dseseItI st
j
t
t
jj
−−− ∫+= ββ ϕϕϕ H
in particular
.))(())0(())(( )(
0
0
0
0
0 dseseITI sT
j
T
T
jj
−−− ∫+= ββ ϕϕϕ H
From (15) and [5, Lemma 2.16] we have
. ,))(())(( )(
0
0
)(
0
0
0
0
0
∞+→→ −−−− ∫∫ jdsesdses sT
T
sT
j
T
ββ ϕϕ HH
Therefore,
=+≤ −−−
+→+→ ∫ dseseITI sT
T
T
j
j
j
j
)(
0
0
0
0
0
0 ))(())0((lim))((lim ββ
∞∞
ϕϕϕ H .
,))(())0(())0((lim))(( 00
00000
TT
jj
eTIeIITI ββ
∞
ςϕϕϕϕ −−
+→
+≤⎥⎦
⎤
⎢⎣
⎡ −+=
where ς does not depend on .00 >T On the other hand, from (15) we have
≥
+→
))((lim 0TI jj
ϕ
∞
)).(),((
2
))(())(()(lim
2
1
0000002001
2
0 TuTuTuJTuJT
Xjj
′+−+≥
+→
βϕ
∞
Therefore, we obtain: 022
2
1
2
1 T
X ea βςξ −+≤ .00 >∀T Thus, .
X
a ξ≤
The Theorem is proved.
Automatic feedback control for one class of contact piezoelectric problems
Системні дослідження та інформаційні технології, 2014, № 1 67
APLICATION
Let us apply main Theorem 3 to Problem (2).
Corollary. Under listed above assumptions on parameters of Problem (2) all
statements of Theorem 3 for m-semiflow G defined in (12) hold.
In particular, for any Vu ∈ such that HuA ∈ there exist such functionals
1G and 2G such that Assumption )(J holds and .}{)( uZ =G
CONCLUSIONS
For one class of feedback automatic control problems in sence of the global
attractor theory the dynamics of solutions is investigated. In particular, we
concider the mathematical model of contact piezoelectric problem with
discontinuous interaction function which can be represented as the difference of
subdifferentials.
A priory estimates for weak solutions of studied problem in the phase spase
are deduced. This contributes to obtain the existence of the weak solutions and
their properties.
The existence of global attractor for generated multi-valued semiflow is
proved. The structural properties of the limit sets are studied. These results are
applied to the considered piezoelectric problem. Thus, it became possible to
forecast the long-term behavior of state function and to direct the investigated
system to the desired asymptotic level.
This research was partially supported by Grants of the President of Ukraine
GP/f44/076, GP/F49/070 and Grant of NAS of Ukraine 2273/13.
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Received 18.11.2013
From the Editorial Board: the article corresponds completely to submitted manuscript.
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