Combined computational-experimental approach towards ...

Combined computational-experimental approach

towards quantifying the structure resilience

Prof. Adnan Ibrahimbegovic, (Classe Exceptionnelle)

Univ. Technologie Compiegne/ Sorbonne Universites, Paris, France

Acknowledgements : “Structures under extreme conditions”

MENRT, EDF, CEA/DAM, IRSN …

Two hundred years of modeling of concrete and challenges

for the next century (Adnan Ibrahimbegovic, France)

Colosseum, Rome

- Studies : PhD Structural Eng. Mechanics Materials: University of California, Berkeley, USA 1989Habilitation in Mechanics: Université Pierre et Marie Curie, Paris, France 1997

Fullbright Fellowship for Yugoslavia (1 /8 excellence awards) 1986« George and Helen Popert » Scholarship, University of California, Berkeley 1987UC Berkeley Regents Scholarship, University of California, Berkeley 1988

NSERC International Fellowship, Canada : 1994Hôte académique, Ecole Polytechnique Fédérale, Lausanne, Switzerland 1998-9, 2000-5

NATO Fellowship for Croatia, Slovenia 2005, 2006

Alexander von Humboldt Research Award ‘Technischen Mechanik’, Germany 2005Fellow IACM Award, International Association of Computational Mechanics 2006Slovenian Science Foundation Research Award, Slovenia 2007Classe Exceptionnelle of University Professors (CNU60), France 20092010: France-India; 2011: France-Berkeley; 2012: Chair Claude Levy-Strauss USP Brazil;2013 Chair Asgard Norway; 2014: TUBITAK Professor TU Istanbul, Turkey;2014: OSCE Professor KAIST S. Korea; 2014: Mercator-Professor TU-Braunschweig, Germany2015 IUF – Institut Universitaire de France - Membre Senior

- Studies Awards :

… in recognition of a researcher's entire achievements to date to academics whose fundamental discoveries, new theories, or

insights have had a significant impact on their own discipline and who are expected to continue producing

cutting-edge achievements in future …

Professor Adnan Ibrahimbegovic, Chaire de MécaniqueE-mail: [email protected]

- Carrier Awards :

Evidence of efforts and ability to inspire young researchers:

Former: post-doc (5), thesis (31) + Habilitations: (5) current positions

of my former students:

-with each of the top engineering schools in Paris (ENPC, ECP, ESTP);

-with well-known technology institutes (MIT-Boston, PEER Center UC-Berkeley.

UT-Compiegne, INSA-Toulouse, Univ. Nantes, Univ. Lille);

-with a number of French industry leaders (AREVA, EDF, Lafarge, Renault);

-with computer software developers (ALTAIR, ESI, SAMTECH);

-and university professors in 10 countries (France, Mexico, Czech Republic,

Slovenia, Vietnam, Algeria, Bosnia, Hungary, Turkey, Croatia)Current: -post-docs (2): E. Marenic, M. Nikolic

-doct. students (9): A. Boujelben, X-N. Do,

E. Hajdo (co-ad. Dr. Dolarevic, Univ. Sarajevo),

E. Hadzalic, I. Imamovic, E. Karavelic ( “ ),

T. Rukavina (co-ad. Dr.. Kozar. Univ. Rijeka),

M. Sarfaraz (co-ad. Dr. Matthies, TU Braunschweig)

A. Stanic (co-advisor Dr. Brank, Univ. Ljubljana).

I Research Background & Accomplishments [past & current works](b) Identifying some of the key previous research accomplishments

Chaire de Mécanique « PICARDie »

Lecture outline:

1. Resilience quantification = system of systems

2. Material vs. structure: probability aspects

3. Combined extreme loading conditions

(earthquake, tsunamis, explosions, fires)

4. Conclusions

Pr Adnan Ibrahimbegovic

6

Earthquakes: First cause of Human Casualties due to Natural Disasters

Worldwide

Assisi, IT, 1997Azores, PT, 1998 Athens, GR, 1999

Molise, IT, 2002

Turkey, 1999Iran, 2003

Japan, 2004

Material vs. structure: probability

World seismic map

--Worst case scenario:i) Cooling liquid loss in the

case of ‘extreme accident’

in a nuclear power plant

ii) Durability issues

Q: Crack spacing and opening ? Collaboration : EDF, IRSN,

CE

Nuclear power plant: Durability problem (30 60 years !)

ENS/LMT-thesis D. Markovic [2001-2004], N. Dominguez [2001-2005]S. Melnyk [2004-2007], A. Kucerova, [2004-2007], M. Hautefeuille [2005-2009], B-H. Pham [2006-2009], A. Boulkertous [2005-9], N. Benkemoun [2007-2010],B. Ayhan [2009-2013], M. Jukic [2010-2013], V-M. Ngo [2011-2014] …


Conclusions (in 1990): Solution methods under control

Need for better interpretations of inelastic failure mechanisms

Performance based design – early works 1992

at UC Berkeley, USA SAP, CSI


New Issues:

RESILIENCE-BASED

DESIGN (better

understandig of damage

Mechanisms …

Different sources

of damping -

-new idea:

avoid Rayleigh

(non-physical )

Damping …–

Move from Structural

to Material

Point of view

P. Jehel, A. Ibrahimbegovic, P. Leger, L. Davenne Concrete Comp. [2010]


Maquette CAMUS 2000

Fissuration ˆ la base dÊÕun mur apr�s essai

National Project CAMUS-2000

Seismic response of RC walls with/without torsion(thesis: G. Casaux, enc.: J. Mazars, L. Davenne, F. Ragaueneau,A Ibrahimbegovic)

Partners : LMT-Cachan, INSA-Lyon, LGS/ CEA Sacley …

Funding: Ministry of Equipment

Reduced Reinforcement. … “French Walls”

Davenne, Ragueneau, Mazars, Ibrahimbegovic [2003] Comp.Struct.

-Collab.: Ecole Polytechnique, Montreal, Quebec, Canada,

University of California, Berkeley, USA

University of Ljubljana, Slovenia

Technical University of Istanbul, Turkey

Local measurements

+ result interpretation


Conclusions:

Rayleigh damping (single parameter) CAN NOT match all 3 phases

not the same cumulative damage !

Model based on ENERGY criterion (neither stress nor strain), e.g. fracture energy Gf

to obtain the same damage (merging force/ disp. based criteria

-earthquake structural response: nonlinear dynamics & damping


Génie Civil et Environnement

Benchmark EDF

Computed results

Delaplace, Ibrahimbegovic [2006] IJNME, Brancherie, Ibrahimbegovic [2009] EC

Mazars E E (1-d) ; d € [0,1]

Questions (… with no answer in year 2000):

-prediction of complex crack patterns with proper nature of dissip.vol./surf. ?

-multi-physics extension of failure description ?

Nooru-Mohamed, TU Delft

experiment


Benchmark EDF

Result : phenomenological models

are neither sufficiently robust

nor predictive under

non-propor. loading

- - - - - - - - - - - - - - - - - -

Guiding principles for model construction:

-separate complexities: to each mechanism its own criterion

-real nature of dissip. In fracture prob. volume vs. surface

-const. law «only» not enough : must address «FEM» issues

-model parameters in dynamics – related to fracture energy (Gf)


1st class of problems: Structural point of view

micro-macro dedicated representation of

inelastic fracture of a massive structure without

detailed representation of damaged zone

“Macro” crack accompanied by large fracture process zone


+ condition of stress orthogonality

multi-scale interpretation:

total dissipation additive

Ibrahimbegovic, Brancherie [2003] CM, ‘”Crisfield issue”

Original approach

Failure of massive structures

Localisation problem:

σ = cst.

Gf


D. Brancherie, A. Ibrahimbegovic [2009] Eng. Comp.

Gf

in Dynamics:

Damage model is not enough

no residual deformation need coupled

damage-plasticity:

s

Ce

D-1

e = ep + ed + ee

A. Ibrahimbegovic, D. Markovic, F. Gatuingt [2009] REEF


-model criteria: plasticity + damage + localization

-internal variables: plasticity + damage + localization


-model parameter identification procedure: plasticity + damage + localization


-coupled damage plasticity model

representing 3 phase response:

evolution equations: operator split

-experimental vs. numerical results

A. Ibrahimbegovic, P. Jehel, L. Davenne [2008] Computational Mechanics

P. Jehel, A. Ibrahimbegovic, P. Leger, L. Davenne [2009] Concrete. Comp.


-linear hardening model

additive structure of compliance

for computational robustness

(no need for local iterations) !

Very robust computational model

(FULLY IMPLICIT CODE

result quality guaranteed ! )


-stress-strain loop: softening damage vs. hardening damage

-time history: i) loading, ii) displacement, iii) force-displacement


23

Reinforced concrete frames is the most widely

used material in civil construction.

Structural designs apply standard design codes:

EC2, UK code, BS8110, ACI 318 with different

limitations in concrete and steel material.

Standard design procedures: 1- Linear analysis

(moment, shear , axial force); 2- Ultimate analysis

for cross-section(reinforcement area and stirrup); 3-

Then check other conditions ( deflection, buckling,

cracking)

23Idea: Stress-Resultant models for efficient comput. and design reinforced concrete frames

Reinforced concrete structures: standard vs. performance based design

This is “true” plastic hinge !


24

2- Semi-global

3- Local model

Multi-layer model

(Pham, Davenne, Brancherie , Ibrahimbegovic [2010]

CC)

Moderate computational effort

2D model predicting crack spacing

,(Ibrahimbegovic, Boulkertous, Davenne [2010\

IJNME)

Large computational effort

3

Stress-resultant models for RC frame structures performance-based design

1D stress-resultant model for truss / beam failure

(Ibrahimbegovic, Brancherie [2003] CM,

Pham, Brancherie, Ibrahimbegovic [2010] CM)

Efficient computations

1- Global level


able to capture the size effect ?

2nd class of problems: Material point of view:

interpretation of inelastic behavior mechanisms through

multi-scale analysis at strongly coupled scales

of 3 pt. bending test

Goal: predict material response from finer scales !


Typical test :

3-pts. bending

Multi-scale model:

uM – macroscale displacement

um,e - microscale displacement

ξm - internal variables

Πa - energy

a=M strain energy at macroscale

a=m strain energy at microscale

a=interface scale coupling condition

a=ext external force energy

Model problem:

2 phase material

(porous media)


-color code: matrix – blue, inclusions – green, interface -

red

Current works: 3D microstructure representation

Voronoi cell representation + cohesive forces

(Benkemoun, Hautefeuille,Colliat, Ibrahimbegovic [2010] IJNME)Material vs. structure: probability

Example: Simple tension test

force-displacement diagrams / contours of displacement / broken bars

- result invariance: mesh objectivity / isotropy


Uni-axial compression test

Biaxial compression test

Cracks: Biaxial vs. Simple Comp. Test


Tension test

– 2D repres.

of porous

material

a) Non-structured FE mesh b) Structured FE mesh(similar nb. FE in each mesh, but elements in mesh a) distorted + node numberiing)

(Hautefeuille, Melnyk, Colliat, Ibrahimbegovic [2009] EC)

Statistics of computed response

Mean response + st. dev.

Porosity histogram / f-u realizations

Heterogeneities !H. Matthies[2006]

, NATO-ARW

Computed diagram:

Force-imposed displacement

--- non-structured FE mesh [CPU time: 11774 s]

--- structured FE mesh [CPU time: 646 s]

Heterogeneity, probabilistic description and size effect:


• chosen Lc = 0,01 m

(Matthies [2007])

Error in covariance repres. with: 5, 10, 50 KL modes + exact



(Colliat, Hautefeuille, Ibrahimbegovic, Matthies [2006] CRAS)

Distribution of max force -

Fractals at 10%:

Short 3.35 MN

Medium 2.90 MN

Long 2.70 MN

Conclusions:

1. Lc introduces the notion of scale

2. Quasi-fragile mater. size effect !

3. Extension of “weak link” (Weibull [1951]

Bazant [1995]



Chaire de Mécanique « PICARDie »

Lecture outline:





4. Conclusions


Tsunami risk map

Failure of Tacoma Bridge (US) under

wind excitation in 1940

Structural Vulnerability has many other facets

Combined extreme loads

FSI (existing) software coupling Open-FOAM + FEAP (no com. codes !)

-Nested parallelization

Remark:

-other codes

(e.g. Chaire ESI ?)

Kassiotis, Ibrahimbegovic, Niekamp,

Matthies [2011] Comp. Mech.


37

2004 Sumatra, Indonesia, Earthquake 2011 Eastern Japan Earthquake

Tsunami can bring other concurrent hazards (fires, landslides, industrial disasters, etc.)

Getty Images

Structural Vulnerability has many facets:

tsunamis + fires

Tsunami risk map


38

Structural Vulnerability has many facets:

terrorist attack + fires

The Murrah

Federal Building

(Oklahoma City)

before and after

the car bomb

attack of 1995

World

Trade

Center,

Sept 11

Problem: projectile impact

(e.g. nuclear power plant,

storage bldg.) ?

CEA: Dept. Military Appl.


39

39

Previous design: impact by “small’ plane, Cesna

(commercial plane P(impact) < 1e-07)

g*

Ibrahimbegovic, Herve, Villon, Eng. Comp. [2009]

Airplane impact on massive struct. (CEA/ Dept. Applications Militaires)

Proposed refined design: Hard vs. Soft impact + field transfer

• 1D model projectile (mass+spring)

• Angle of impact = 90° response spectrum

• Target infinitely rigid


Finite rotation shell model (large rotations, shell instability)

… A. Ibrahimbegovic et al. [1994, 1997,2001] CMAME, ASME-AMR, IJNME

u = 4[mm] u = 5[mm] u = 6[mm]

Viscoplasticité

Sheet metal forming

Large strain plasticity (large strain plasticity, necking instability)

… A. Ibrahimbegovic et al. [1994, 1999, 2000] IJSS, CMAME, CS

Research Expertise: 3D Finite Def. Plasticity

FEAP

UC Berkeley

Zienkiewicz & Taylor

[2005] Elsevier


Multiphysics: Structural Vulnerability has many other facets

41

WTC, September 11/01


: Dujc, Brank, Ibrahimbegovic, CMAME [2010]

Steel structures


Localized failure – finite strain plasticity thermo-mechanical

coupling

Example: Mesh Objectivity

L1 =1m, A =1mm2 θ = 100t

U = 0

θ = 0

u = 2t (mm)

Material Properties Value Dimension

Young modulus 205000 MPa

Initial yield stress 250 MPa

Ultimate stress 300 MPa

Plastic hardening modulus 20000 MPa

Localized softening modulus -45 MPam-1

Mass Density 7.865 10-9 Ns2mm-4

Thermal conductivity 45 N s-1K-1

Heat specific 0.46 109 mm2s-2K-1

Thermal elongation 0.00001

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

50

100

150

200

250

300

- 5 elements

Force (N)

Displacement (mm)

+ 7 elements

* 9 elements

0 0.0020.0040.0060.008 0.01 0.0120.0140.016

50

100

150

200

250

300

Displacement (mm)

Force (N)Temperature independent properties

Temperature dependent propertiesMaterial properties

Temp. dependence (EC 1993)

Ngo, Ibrahimbegovic, Brancherie [2014] Coupled Systems Mechanics


12/2/2015Localized failure for thermo-

mechanical problem44

Truss Instability at Finite Deformation

0 0.1 0.2 0.3 0.4 0.5 0.6-10

010

20

30

40

50

60

Displacement (m)

Force (kN)

Thermo-mechanical loadingMechanical loading

Temperature Distribution in the Truss before collapse

Case 1 Case 2Load/displacement curve


Lecture Outline :





4. Conclusions

Chaire de Mécanique « PICARDIE »


Chaire de Mécanique « PICARDIE »

MONOGRAPHS/

TEXTBOOKS :

… Springer 2009

… Hermes / Lavoisier 2006

… Springer 2008(AI, M. Zlatar)

… Springer 2007(AI, I. Kozar)

Perspectives for Resilience Studies: System vs. Structure !

Studies at the scale of complex structure

currently needed for sensitive structures (nuclear)

Objectives: Crack patterns (spacing, opening)

=> fluid flow through cracks, durability

Multi-physics / Multi-phenomena

Structures of large size

=> Multi-scale analysis (space and time)

and code coupling

Uncertainties

Probabilistic analysis

Conclusion: the biggest European computer

(with CEA / DAM used for nuclear simulations)

will also be used for earthquake simulations !

Conclusions

Perspectives for Resilience Studies: System vs. Structure !

Studies at at scale of (mega-) cities

Complex systems with different interactions

vert.

trans.

long.

Macro-elements:

piping, soil, joints

Echelle du quartier

Interaction sol-structures

Fragility curves

scenarios

Probabilistic comp.

Population in urban areas :

1950 : < 30%

2010 : 50%

2030 : > 60%

Conclusions

Perspectives for Resilience Studies: System vs. System of systems !

Conclusions

Gracias por su atención.

Thank you for your attention.

Merci bien de votre attention.

Combined computational-experimental approach towards ...

Documents

Transcript of Combined computational-experimental approach towards ...