+ All Categories
Home > Documents > Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 ·...

Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 ·...

Date post: 21-May-2020
Category:
Upload: others
View: 3 times
Download: 0 times
Share this document with a friend
52
Dimension Reduction Problems for Multiscale Materia in Nonlinear Elasticity. Part 3: simultaneous homogenization and dimension reduction Elisa Davoli CENTRAL Summerschool Humboldt-Universit at zu Berlin, August 29th-September 2nd 2016. Elisa Davoli Multiscale Dimension Reduction 1 / 37
Transcript
Page 1: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Dimension Reduction Problems for Multiscale Materialsin Nonlinear Elasticity.

Part 3: simultaneous homogenization and dimensionreduction

Elisa Davoli

CENTRAL SummerschoolHumboldt-Universitat zu Berlin, August 29th-September 2nd 2016.

Elisa Davoli Multiscale Dimension Reduction 1 / 37

Page 2: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Overview

Part 1: dimension reduction problem for homogeneous nonlinearly elasticplates.

Part 2/tutorial: static Γ-convergence, and the notion of 2-scale convergence.

Part 3: simultaneous homogenization and dimension reduction.I MotivationI A little bit of historyI Homogenization under physical growth conditions

Elisa Davoli Multiscale Dimension Reduction 2 / 37

Page 3: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Motivation

In many applications: establish the macroscopic behavior of a material which is“mycroscopically” heterogeneous, in order to study some characteristics of theheterogeneous material (for example its thermal or electrical conductivity).

⇓Homogenization problems for thin structures.

Elisa Davoli Multiscale Dimension Reduction 3 / 37

Page 4: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Dimension reduction in nonlinear elasticity

Scaling of the applied loads in terms of the thickness parameter

Different scalings of the elastic energy

Different limit models.

Elisa Davoli Multiscale Dimension Reduction 4 / 37

Page 5: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Periodic homogenization and dimension reduction

Scaling of the applied loads in terms of the thickness parameter

Different scalings of the elastic energy & different ratio thickness/periodicityscale(s)

Different limit models.

Elisa Davoli Multiscale Dimension Reduction 4 / 37

Page 6: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

A (very) brief history of homogenization and dimensionreduction

Seminal papers: membrane regime

J-F. Babadjian - M. Baia (2006),

A. Braides - I. Fonseca - G. A. Francfort (2000)

p-growth

1

β|F |p − β ≤W (F ) ≤ β(1 + |F |p).

Incompatible with the physical requirement that the energy blows up undervery strong compressions.

W (F )→ +∞ as detF → 0+.

Homogenization under physical growth conditions for the energy density, at leastfor models corresponding to very small loads f h ≈ hα, α > 2 (Von Karman platetheories) or α = 2 (Kirchhoff plate theories)?

Elisa Davoli Multiscale Dimension Reduction 5 / 37

Page 7: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

A (very) brief history of homogenization and dimensionreduction

Seminal papers: membrane regime

J-F. Babadjian - M. Baia (2006),

A. Braides - I. Fonseca - G. A. Francfort (2000)

p-growth

1

β|F |p − β ≤W (F ) ≤ β(1 + |F |p).

Incompatible with the physical requirement that the energy blows up undervery strong compressions.

W (F )→ +∞ as detF → 0+.

Homogenization under physical growth conditions for the energy density, at leastfor models corresponding to very small loads f h ≈ hα, α > 2 (Von Karman platetheories) or α = 2 (Kirchhoff plate theories)?

Elisa Davoli Multiscale Dimension Reduction 5 / 37

Page 8: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

A brief history of homogenization and dimension reduction

Seminal papers: membrane regime

J-F. Babadjian - M. Baia (2006),

A. Braides - I. Fonseca - G. A. Francfort (2000)

p-growth

Incompatible with the physical requirement that the energy blows up undervery strong compressions.

W (F )→ +∞ as detF → 0+.

P. Hornung - S. Neukamm - I. Velcic (2014), S. Neukamm - I. Velcic (2013), I.Velcic (2014), L. Bufford - E.D. - I. Fonseca (2015): homogenization anddimension reduction under physical growth conditions for the energy density(f h ≈ hα, α ≥ 2).

Elisa Davoli Multiscale Dimension Reduction 5 / 37

Page 9: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Homogenization with physical growth conditions for amultiscale thin plate[P. Hornung - S. Neukamm - I. Velcic (2014)], [L. Bufford - E.D. - I. Fonseca (2015)]

Reference configuration:Ωh := ω × (− h

2 ,h2 )

ω=bounded Lipschitz domain in R2, whose boundary is piecewise C 1,

h > 0=thickness parameter.

two in plane homogeneity scales - a coarser one and a finer one - ε(h) andε2(h),

h and ε(h) are monotone decreasing sequences of positive numbers,h→ 0, and ε(h)→ 0 as h→ 0.

Elisa Davoli Multiscale Dimension Reduction 6 / 37

Page 10: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Homogenization with physical growth conditions for amultiscale thin plate[P. Hornung - S. Neukamm - I. Velcic (2014)], [L. Bufford - E.D. - I. Fonseca (2015)]

Reference configuration:Ωh := ω × (− h

2 ,h2 )

ω=bounded Lipschitz domain in R2, whose boundary is piecewise C 1,

h > 0=thickness parameter.

two in plane homogeneity scales - a coarser one and a finer one - ε(h) andε2(h),

h and ε(h) are monotone decreasing sequences of positive numbers,h→ 0, and ε(h)→ 0 as h→ 0.

Elisa Davoli Multiscale Dimension Reduction 6 / 37

Page 11: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Homogenization with physical growth conditions

The rescaled nonlinear elastic energy:

J h(v) :=1

h

ˆΩh

W( x ′

ε(h),

x ′

ε2(h),∇v(x)

)dx

for every deformation v ∈W 1,2(Ωh;R3).

Kirchhoff’s plate theory: we consider sequences of deformationsvh ⊂W 1,2(Ωh;R3) verifying

lim suph→0

J h(vh)

h2< +∞.

Elisa Davoli Multiscale Dimension Reduction 7 / 37

Page 12: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Our goal

To identify the effective energy associated to the rescaled elastic energiesJ h(vh)h2

for different values of

γ1 := limh→0

h

ε(h)

and

γ2 := limh→0

h

ε2(h),

i.e. depending on the interaction of the homogeneity scales with the thicknessparameter.

Five regimes: γ1 = +∞, 0 < γ1 < +∞, γ1 = 0 and γ2 = +∞, 0 < γ2 < +∞,γ2 = +∞.

Elisa Davoli Multiscale Dimension Reduction 8 / 37

Page 13: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Assumptions on the stored energy density

W : R2 × R2 ×M3×3 → [0,+∞)

(H0) (·, ·,F ) 7→W (·, ·,F ) is measurable and Q-periodic, W (y , z , ·) is continuous,

(H1) W (y , z ,RF ) = W (y , z ,F ) for every F ∈M3×3 and for all R ∈ SO(3) (frameindifference),

(H2) W (y , z ,F ) ≥ C1 dist2(F ;SO(3)) for every F ∈M3×3 (nondegeneracy),

(H3) there exists δ > 0 such that W (y , z ,F ) ≤ C2 dist2(F ;SO(3)) for every

F ∈M3×3 with dist(F ;SO(3)) < δ,

(H4) lim|G |→0W (y ,z,Id+G)−Q(y ,z,G)

|G |2 = 0, where Q(y , z , ·) is a quadratic form on

M3×3.

Elisa Davoli Multiscale Dimension Reduction 9 / 37

Page 14: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Assumptions on the stored energy density

W : R2 × R2 ×M3×3 → [0,+∞)

(H0) (·, ·,F ) 7→W (·, ·,F ) is measurable and Q-periodic, W (y , z , ·) is continuous,

(H1) W (y , z ,RF ) = W (y , z ,F ) for every F ∈M3×3 and for all R ∈ SO(3) (frameindifference),

(H2) W (y , z ,F ) ≥ C1 dist2(F ;SO(3)) for every F ∈M3×3 (nondegeneracy),

(H3) there exists δ > 0 such that W (y , z ,F ) ≤ C2 dist2(F ;SO(3)) for every

F ∈M3×3 with dist(F ;SO(3)) < δ,

(H4) lim|G |→0W (y ,z,Id+G)−Q(y ,z,G)

|G |2 = 0, where Q(y , z , ·) is a quadratic form on

M3×3.

Elisa Davoli Multiscale Dimension Reduction 9 / 37

Page 15: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Change of variables

We focus on the asymptotic behavior of sequences of deformationsuh ⊂W 1,2(Ω;R3) satisfying the uniform energy estimate

Eh(uh) :=

ˆΩ

W( x ′

ε(h),

x ′

ε2(h),∇hu

h(x))dx ≤ Ch2 for every h > 0.

where Ω := Ω1 = ω × (− 12 ,

12 ), and ∇hu(x) :=

(∇′u(x)

∣∣∂x3u(x)

h

)for a.e. x ∈ Ω.

RemarkFor W independent of y and z , such scalings of the energy lead to Kirchhoff’snonlinear plate theory [G. Friesecke - R.D James - S. Muller (2006)].

Elisa Davoli Multiscale Dimension Reduction 10 / 37

Page 16: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Compactness

Theorem (G. Friesecke - R.D James - S. Muller (2006))

Let uh ⊂W 1,2(Ω;R3) satisfy the uniform energy estimate. Then, there exists amap u ∈W 2,2(ω;R3) such that, up to subsequences,

uh −

Ω

uh(x) dx → u strongly in L2(Ω;R3)

∇huh → (∇′u|nu) strongly in L2(Ω;M3×3),

with∂xαu(x ′) · ∂xβu(x ′) = δα,β for a.e. x ′ ∈ ω, α, β ∈ 1, 2

andnu(x ′) := ∂x1u(x ′) ∧ ∂x2u(x ′) for a.e. x ′ ∈ ω.

Elisa Davoli Multiscale Dimension Reduction 11 / 37

Page 17: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

The limit model

Theorem (L. Bufford - E.D. - I. Fonseca (2015))

Let γ1 ∈ [0,+∞] and let γ2 = +∞. Let uh ⊂W 1,2(Ω;R3) andu ∈W 2,2(ω;R3) be as in Theorem 1. Then

lim infh→0

Eh(uh)

h2≥ Eγ1 (u).

Moreover, for every u ∈W 2,2(ω;R3) as in Theorem 1, there exists a sequenceuh ⊂W 1,2(Ω;R3) such that

lim suph→0

Eh(uh)

h2≤ Eγ1 (u).

Elisa Davoli Multiscale Dimension Reduction 12 / 37

Page 18: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

The limit model

Theorem (L. Bufford - E.D. - I. Fonseca (2015))

The effective energy is given by

Eγ1 (u) :=

1

12

´ω

Qγ1

hom(Πu(x ′)) dx ′ if u is as in Theorem 1,

+∞ otherwise in L2(Ω;R3),

where Πu is the second fundamental form associated to u,

Πuα,β(x ′) := −∂2

α,βu(x ′) · nu(x ′) for α, β = 1, 2,

nu(x ′) := ∂1u(x ′) ∧ ∂2u(x ′), and Qγ1

hom is a quadratic from dependent on thevalue of γ1.

Elisa Davoli Multiscale Dimension Reduction 13 / 37

Page 19: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

The limit model

Theorem (0 < γ1 < +∞.)

In particular, if 0 < γ1 < +∞, for every A ∈M2×2sym

Qγ1

hom(A) := inf

ˆ(− 1

2 ,12

)×Q

Qhom

(y ,( x3A + B 0

0 0

)+ sym

(∇yφ1(x3, y)

∣∣∣∂x3φ1(x3, y)

γ1

)):

φ1 ∈W 1,2((− 1

2 ,12 );W 1,2

per(Q;R3)), B ∈M2×2

sym

;

where

Qhom(y ,C ) := infˆ

Q

Q(y , z ,C + sym

(∇φ2(z)

∣∣0)) : φ2 ∈W 1,2per(Q;R3)

for a.e. y ∈ Q, and for every C ∈M3×3

sym.

Elisa Davoli Multiscale Dimension Reduction 14 / 37

Page 20: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

The limit model

Theorem (γ1 = +∞)

If γ1 = +∞, for every A ∈M2×2sym

Q∞hom(A) := inf

ˆ(− 1

2 ,12

)×Q

Qhom

(y ,( x3A + B 0

0 0

)+ sym (∇yφ1(x3, y)|d(x3))

): d ∈ L2((− 1

2 ,12 );R3),

φ1 ∈ L2((− 12 ,

12 );W 1,2

per(Q;R3)), and B ∈M2×2sym

.

Elisa Davoli Multiscale Dimension Reduction 15 / 37

Page 21: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

The limit model

Theorem (γ1 = 0)

If γ1 = 0, for every A ∈M2×2sym

Q0

hom(A) := inf

ˆ(− 1

2 ,12

)×Q

Qhom

(y ,( x3A + B 0

0 0

)

+ sym

sym∇yξ(x3, y) + x3∇2yη(y) g1(x3, y)

g2(x3, y)g1(x3, y) g2(x3, y) g3(x3, y)

:

ξ ∈ L2((− 1

2 ,12 );W 1,2

per(Q;R2)), η ∈W 2,2

per(Q),

gi ∈ L2((− 1

2 ,12 )× Q), i = 1, 2, 3,B ∈M2×2

sym

.

Elisa Davoli Multiscale Dimension Reduction 16 / 37

Page 22: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

A few questions

Why are there pointwise minimizations with respect to gradients in theperiodicity variables?

How does the value of γ1 determine the different minimization problems?

Where does two-scale convergence come into play?

Elisa Davoli Multiscale Dimension Reduction 17 / 37

Page 23: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality for γ1 ∈ (0,+∞)(sketch)1. Convergence of scaled stresses

|√FTF − Id |2 ≤ Cdist2(F ;SO(3)) ≤W (y , z ,F )

&

Uniform energy estimate

Uniform bound on the L2-norm of the sequence of linearized stresses

E h(x) :=

√(∇huh(x))T∇huh(x)− Id

h.

Elisa Davoli Multiscale Dimension Reduction 18 / 37

Page 24: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality for γ1 ∈ (0,+∞)(sketch)1. Convergence of scaled stresses

|√FTF − Id |2 ≤ Cdist2(F ;SO(3)) ≤W (y , z ,F )

&

Uniform energy estimate

Uniform bound on the L2-norm of the sequence of linearized stresses

E h(x) :=

√(∇huh(x))T∇huh(x)− Id

h.

Elisa Davoli Multiscale Dimension Reduction 18 / 37

Page 25: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality for γ1 ∈ (0,+∞)(sketch)1. Convergence of scaled stresses

Linearization of the stored energy density around the identity

lim infh→0

Eh(uh)

h2u lim inf

h→0

ˆΩ

Q( x ′

ε(h),

x ′

ε2(h),E h(x)

)dx .

Key point: to identify the multiscale limit of the sequence E h.Key ingredient: multiscale convergence adapted to dimension reduction.

Elisa Davoli Multiscale Dimension Reduction 19 / 37

Page 26: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality for γ1 ∈ (0,+∞)(sketch)1. Convergence of scaled stresses

Linearization of the stored energy density around the identity

lim infh→0

Eh(uh)

h2u lim inf

h→0

ˆΩ

Q( x ′

ε(h),

x ′

ε2(h),E h(x)

)dx .

Key point: to identify the multiscale limit of the sequence E h.Key ingredient: multiscale convergence adapted to dimension reduction.

Elisa Davoli Multiscale Dimension Reduction 19 / 37

Page 27: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality for γ1 ∈ (0,+∞)(sketch)

Definition (G. Allaire (1992), D. Lukkassen - G. Nguetseng - P. Wall(2002), G. Nguetseng (1989), G.Allaire - M. Briane (1996))

Let u ∈ L2(Ω× Q × Q) and uh ∈ L2(Ω). We say that uh converges weakly

3-scale to u in L2(Ω× Q × Q), and we write uh3−s− u, if

ˆΩ

uh(ξ)ϕ(ξ,

ξ

ε(h),

ξ

ε2(h)

)dξ →

ˆΩ

ˆQ

ˆQ

u(ξ, η, λ)ϕ(ξ, η, λ) dλ dη dξ

for every ϕ ∈ C∞c (Ω;Cper(Q × Q)).

Elisa Davoli Multiscale Dimension Reduction 20 / 37

Page 28: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality for γ1 ∈ (0,+∞)(sketch)

Definition (S. Neukamm (2010))

Let u ∈ L2(Ω× Q × Q) and uh ∈ L2(Ω). We say that uh converges weakly

dr-3-scale to u in L2(Ω× Q × Q), and we write uhdr−3−s− u, if

ˆΩ

uh(x)ϕ(x ,

x ′

ε(h),

x ′

ε2(h)

)dx →

ˆΩ

ˆQ

ˆQ

u(x , y , z)ϕ(x , y , z) dz dy dx

for every ϕ ∈ C∞c (Ω;Cper(Q × Q)).

Remark

Bounded sequences in L2 are precompact with respect to multiscale convergence

Question: how are 3-scale limits, 2-scale limits, and weak L2-limit related? On theblackboard!

Elisa Davoli Multiscale Dimension Reduction 21 / 37

Page 29: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality for γ1 ∈ (0,+∞)(sketch)

Definition (S. Neukamm (2010))

Let u ∈ L2(Ω× Q × Q) and uh ∈ L2(Ω). We say that uh converges weakly

dr-3-scale to u in L2(Ω× Q × Q), and we write uhdr−3−s− u, if

ˆΩ

uh(x)ϕ(x ,

x ′

ε(h),

x ′

ε2(h)

)dx →

ˆΩ

ˆQ

ˆQ

u(x , y , z)ϕ(x , y , z) dz dy dx

for every ϕ ∈ C∞c (Ω;Cper(Q × Q)).

Remark

Bounded sequences in L2 are precompact with respect to multiscale convergence

Question: how are 3-scale limits, 2-scale limits, and weak L2-limit related? On theblackboard!

Elisa Davoli Multiscale Dimension Reduction 21 / 37

Page 30: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality for γ1 ∈ (0,+∞)(sketch)

Theorem (Multiscale limits of scaled gradients)

Let u, uh ⊂W 1,2(Ω) be such that

uh u weakly in W 1,2(Ω).

and

lim suph→0

ˆΩ

|∇huh(x)|2 dx <∞.

Then u is independent of x3.

Moreover, there exist u1 ∈ L2(Ω;W 1,2per(Q)),

u2 ∈ L2(Ω× Q;W 1,2per(Q)), and u ∈ L2

(ω × Q × Q;W 1,2

(− 1

2 ,12

))such that, up

to the extraction of a (not relabeled) subsequence,

∇huh

dr−3−s−

(∇′u +∇yu1 +∇zu2

∣∣∣∂x3 u)

weakly dr-3-scale.

Elisa Davoli Multiscale Dimension Reduction 22 / 37

Page 31: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality for γ1 ∈ (0,+∞)(sketch)

Theorem (Multiscale limits of scaled gradients)

Let u, uh ⊂W 1,2(Ω) be such that

uh u weakly in W 1,2(Ω).

and

lim suph→0

ˆΩ

|∇huh(x)|2 dx <∞.

Then u is independent of x3.Moreover, there exist u1 ∈ L2(Ω;W 1,2per(Q)),

u2 ∈ L2(Ω× Q;W 1,2per(Q)), and u ∈ L2

(ω × Q × Q;W 1,2

(− 1

2 ,12

))such that, up

to the extraction of a (not relabeled) subsequence,

∇huh

dr−3−s−

(∇′u +∇yu1 +∇zu2

∣∣∣∂x3 u)

weakly dr-3-scale.

Elisa Davoli Multiscale Dimension Reduction 22 / 37

Page 32: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality for γ1 ∈ (0,+∞)(sketch)

Theorem (Multiscale limits of scaled gradients)

Moreover,

(i) if γ1 = γ2 = +∞ (i.e. ε(h) << h), then ∂yi u = ∂zi u = 0, for i = 1, 2;

(ii) if 0 < γ1 < +∞ and γ2 = +∞ (i.e. ε(h) ∼ h), then

u =u1

γ1;

(iii) if γ1 = 0 and γ2 = +∞ (i.e. h << ε(h) << h12 ), then

∂x3u1 = 0 and ∂zi u = 0, i = 1, 2.

Question: why do we have such a structure for multiscale limits of scaledgradients? On the blackboard!

Elisa Davoli Multiscale Dimension Reduction 23 / 37

Page 33: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality for γ1 ∈ (0,+∞)(sketch)

Theorem (Multiscale limits of scaled gradients)

Moreover,

(i) if γ1 = γ2 = +∞ (i.e. ε(h) << h), then ∂yi u = ∂zi u = 0, for i = 1, 2;

(ii) if 0 < γ1 < +∞ and γ2 = +∞ (i.e. ε(h) ∼ h), then

u =u1

γ1;

(iii) if γ1 = 0 and γ2 = +∞ (i.e. h << ε(h) << h12 ), then

∂x3u1 = 0 and ∂zi u = 0, i = 1, 2.

Question: why do we have such a structure for multiscale limits of scaledgradients? On the blackboard!

Elisa Davoli Multiscale Dimension Reduction 23 / 37

Page 34: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality for γ1 ∈ (0,+∞)(sketch)2. The rigidity estimate

Theorem (G. Friesecke - R.D. James - S. Muller (2002))

Let γ0 ∈ (0, 1] and let h, δ > 0 be such that

γ0 ≤h

δ≤ 1

γ0.

There exists a constant C , depending only on ω and γ0, such that for everyu ∈W 1,2(ω;R3) there exists a map R : ω → SO(3) piecewise constant on eachcube x + δY , with x ∈ δZ2, and there exists R ∈W 1,2(ω;M3×3) such that

‖∇hu − R‖2L2(Ω;M3×3) + ‖R − R‖2

L2(ω;M3×3)

+ h2‖∇′R‖2L2(ω;M3×3×M3×3) ≤ C‖dist(∇hu;SO(3))‖L2(Ω).

Elisa Davoli Multiscale Dimension Reduction 24 / 37

Page 35: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality3. Compactness of linearized strains

γ1 := limh→0

h

ε(h)∈ (0,+∞)

Apply the theorem with δ = ε(h) and construct maps Rh piecewise constant oncubes of size ε(h) and centers in ε(h)Z2 such that

‖∇huh − Rh‖2

L2(Ω;M3×3) ≤ C‖dist(∇huh;SO(3))‖L2(Ω) ≤ Ch2.

The sequence of linearized strains

G h(x) :=Rh(x ′)T∇hu

h(x)− Id

h

is uniformly bounded in L2.

Elisa Davoli Multiscale Dimension Reduction 25 / 37

Page 36: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality4. Stress-strain relation and liminf inequality

E h(x) :=

√(∇huh(x))T∇huh(x)− Id

h

=

√(Id + hRh(x ′)G h(x))T (Id + hRh(x ′)G h(x))− Id

h

≈ symRh(x ′)G h(x) ≈ sym∇hu

h(x)− Rh(x ′)

h.

The problem becomes:to identify the multiscale limit of the sequence

sym∇hu

h − Rh

h.

Elisa Davoli Multiscale Dimension Reduction 26 / 37

Page 37: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality5. Identification of the limit strain

Idea: rewrite uh as

uh(x) =: uh(x ′) + hx3Rh(x ′)e3 + hrh(x ′, x3)

where

uh(x ′) :=

ˆ 12

− 12

uh(x ′, x3) dx3.

Then

∇huh − Rh

h=(∇′uh − (Rh)′

h+ x3∇′Rhe3

∣∣∣ (Rh − Rh)

he3

)+∇hr

h.

Elisa Davoli Multiscale Dimension Reduction 27 / 37

Page 38: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality5. Identification of the limit strain

Bounded sequences in L2 are precompact with respect to multiscale convergence

∇′uh − (Rh)′

h

3−s− V weakly 3-scale.

By the results by [P. Hornung - S. Neukamm - I. Velcic (2014)] and the relationbetween 3-scale limits and 2-scale limits we only need to show

V (x ′, y , z)−ˆQ

V (x ′, y , ξ) dξ = ∇zv(x ′, y , z)

for some v ∈ L2(Ω× Q;W 1,2per(Q))...

Elisa Davoli Multiscale Dimension Reduction 28 / 37

Page 39: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality5. Identification of the limit strain

...that isˆΩ

ˆQ

ˆQ

(V (x ′, y , z)−

ˆQ

V (x ′, y , ξ) dξ)

: (∇′)⊥ϕ(z)ψ(x ′, y) dx dy dz = 0

for every ϕ ∈ C 1per(Q;R3) and ψ ∈ C∞c (ω;C∞per(Q)), where

(∇′)⊥ϕ(z) :=(− ∂z2ϕ(z)|∂z1ϕ(z)

).

Test functions of the form

(∇′)⊥ϕ( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

).

Elisa Davoli Multiscale Dimension Reduction 29 / 37

Page 40: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality5. Identification of the limit strain

...that isˆΩ

ˆQ

ˆQ

(V (x ′, y , z)−

ˆQ

V (x ′, y , ξ) dξ)

: (∇′)⊥ϕ(z)ψ(x ′, y) dx dy dz = 0

for every ϕ ∈ C 1per(Q;R3) and ψ ∈ C∞c (ω;C∞per(Q)), where

(∇′)⊥ϕ(z) :=(− ∂z2ϕ(z)|∂z1ϕ(z)

).

Test functions of the form

(∇′)⊥ϕ( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

).

Elisa Davoli Multiscale Dimension Reduction 29 / 37

Page 41: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality5. Identification of the limit strain

We need to identify

limh→0

ˆω

∇′uh(x ′)− (Rh)′(x ′)

h: (∇′)⊥ϕ

( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

)dx .

Step 1:

limh→0

ˆω

∇′uh(x)

h: (∇′)⊥ϕ

( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

)dx = 0.

Step 2:ˆΩ

ˆQ

ˆQ

(ˆQ

V (x ′, y , ξ) dξ)

: (∇′)⊥ϕ(z)ψ(x ′, y) dx dy dz = 0.

Step 3:

limh→0

ˆω

(Rh)′(x ′)

h: (∇′)⊥ϕ

( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

)dx = 0

Elisa Davoli Multiscale Dimension Reduction 30 / 37

Page 42: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality5. Identification of the limit strain

We need to identify

limh→0

ˆω

∇′uh(x ′)− (Rh)′(x ′)

h: (∇′)⊥ϕ

( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

)dx .

Step 1:

limh→0

ˆω

∇′uh(x)

h: (∇′)⊥ϕ

( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

)dx = 0.

Step 2:ˆΩ

ˆQ

ˆQ

(ˆQ

V (x ′, y , ξ) dξ)

: (∇′)⊥ϕ(z)ψ(x ′, y) dx dy dz = 0.

Step 3:

limh→0

ˆω

(Rh)′(x ′)

h: (∇′)⊥ϕ

( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

)dx = 0

Elisa Davoli Multiscale Dimension Reduction 30 / 37

Page 43: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality5. Identification of the limit strain

We need to identify

limh→0

ˆω

∇′uh(x ′)− (Rh)′(x ′)

h: (∇′)⊥ϕ

( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

)dx .

Step 1:

limh→0

ˆω

∇′uh(x)

h: (∇′)⊥ϕ

( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

)dx = 0.

Step 2:ˆΩ

ˆQ

ˆQ

(ˆQ

V (x ′, y , ξ) dξ)

: (∇′)⊥ϕ(z)ψ(x ′, y) dx dy dz = 0.

Step 3:

limh→0

ˆω

(Rh)′(x ′)

h: (∇′)⊥ϕ

( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

)dx = 0

Elisa Davoli Multiscale Dimension Reduction 30 / 37

Page 44: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality5. Identification of the limit strain

We need to identify

limh→0

ˆω

∇′uh(x ′)− (Rh)′(x ′)

h: (∇′)⊥ϕ

( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

)dx .

Step 1:

limh→0

ˆω

∇′uh(x)

h: (∇′)⊥ϕ

( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

)dx = 0.

Step 2:ˆΩ

ˆQ

ˆQ

(ˆQ

V (x ′, y , ξ) dξ)

: (∇′)⊥ϕ(z)ψ(x ′, y) dx dy dz = 0.

Step 3:

limh→0

ˆω

(Rh)′(x ′)

h: (∇′)⊥ϕ

( x ′

ε2(h)

)ψ(x ′,

x ′

ε(h)

)dx = 0

Elisa Davoli Multiscale Dimension Reduction 30 / 37

Page 45: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality5. Identification of the limit strain

Idea: the maps Rh are piecewise constant con cubes of size ε(h) and centers inε(h)Z2....

Main difficulty: ...but we have oscillations on cubes of size ε2(h) and centers inε2(h)Z2.

Elisa Davoli Multiscale Dimension Reduction 31 / 37

Page 46: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality5. Identification of the limit strain

Idea: the maps Rh are piecewise constant con cubes of size ε(h) and centers inε(h)Z2....Main difficulty: ...but we have oscillations on cubes of size ε2(h) and centers inε2(h)Z2.

Elisa Davoli Multiscale Dimension Reduction 31 / 37

Page 47: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Proof of the liminf inequality5. Identification of the limit strain

Solution: to distinguish between “bad cubes” and “good cubes” and show thatthe measure of the intersection between ω and the set of “bad cubes” convergesto zero faster than or comparable to ε(h), as h→ 0.

Elisa Davoli Multiscale Dimension Reduction 32 / 37

Page 48: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Final remarks on the case γ1 = 0.

By G. Friesecke, R.D. James and S. Muller’s rigidity estimate: work withsequences of piecewise constant rotations which are constant on cubesof size ε2(h) having centers in the grid ε2(h)Z2.

To identify the limit multiscale stress we need to deal with oscillating testfunctions with vanishing averages on a scale ε(h).

Elisa Davoli Multiscale Dimension Reduction 33 / 37

Page 49: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Final remarks on the case γ1 = 0.

The identification of “good cubes” and “bad cubes” of size ε2(h) is not helpful asthe contribution of the oscillating test functions on cubes of size ε2(h) is notnegligible anymore.

We are only able to perform an identification of the multiscale limit in the caseγ2 = +∞, extending to the multiscale setting the results obtained by I. Velcic.The identification of the effective energy in the case in which γ1 = 0 andγ2 ∈ [0,+∞) remains an open question.

Elisa Davoli Multiscale Dimension Reduction 34 / 37

Page 50: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

References-1

G. Allaire. Homogenization and two-scale convergence. SIAM J. Math. Anal.23 (1992), 1482–1518.

G. Allaire, M. Briane. Multiscale convergence and reiterated homogenisation.Proc. Roy. Soc. Edinburgh Sect. A 126 (1996), 297–342.

J.F. Babadjian, M. Baıa. 3D-2D analysis of a thin film with periodicmicrostructure. Proc. Roy. Soc. Edinburgh Sect. A 136 (2006), 223–243.

A. Braides. Homogenization of some almost periodic coercive functionals.Rend. Naz. Accad. Sci. XL. Mem. Mat. 5 (1985), 313–322.

A. Braides, I. Fonseca, G.A. Francfort. 3D-2D asymptotic analysis forinhomogeneous thin films. Indiana Univ. Math. J. 49 (2000), 1367–1404.

L. Bufford, E. Davoli, I. Fonseca. Multiscale homogenization in Kirchhoff’snonlinear plate theory. Math. Models Methods Appl. Sci. 25 (2015),1765–1812.

Elisa Davoli Multiscale Dimension Reduction 35 / 37

Page 51: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

References-2

S. Muller. Homogenization of nonconvex integral functionals and cellularelastic materials. Arch. Ration. Mech. Anal. 99 (1987), 189–212.

G. Nguetseng. A general convergence result for a functional related to thetheory of homogenization. SIAM J. Math. Anal. 20 (1989), 608–623.

P. Hornung, S. Neukamm, I. Velcic. Derivation of a homogenized nonlinearplate theory from 3d elasticity. Calc. Var. Partial Differential Equations 51(2014), 677–699.

S. Neukamm. Homogenization, linearization and dimension reduction inelasticity with variational methods. PhD thesis, Technische UniversitatMunchen, 2010.

I. Velcic. On the derivation of homogenized bending plate model. Calc. Var.Partial Differential Equations 53 (2015), 561–586.

Elisa Davoli Multiscale Dimension Reduction 36 / 37

Page 52: Dimension Reduction Problems for Multiscale Materials in …ccafm/Archive/... · 2016-09-20 · Overview Part 1: dimension reduction problem for homogeneous nonlinearly elastic plates.

Thank you for your attention!

Elisa Davoli Multiscale Dimension Reduction 37 / 37


Recommended