essi simulator program, current status

Motivation ESSI Simulator System Modeling and Applications Current Work Summary

ESSI Simulator Program, Current Status

N. Tafazzoli, F. Pisanò, J. A. Abbel M., B. Kamrani,C.-G. Jeong, B. Aldridge, R. Roche, A. Kammerer, and

B. Jeremic,

Professor, University of California, Davis, CAFaculty Scientist, Lawrence Berkeley National Laboratory, Berkeley, CA

SMiRT 22San Francisco, August 2013

Jeremic



Outline

Motivation

ESSI Simulator SystemESSI Simulator System

Modeling and ApplicationsPisanò Model, G/Gmax and Damping CurvesContact Base Isolation

Current Work

Summary

Jeremic



Motivation

The ProblemI Modeling and simulation of a realistic nonlinear seismic

response of Nuclear Power Plants

I 3D, inclined seismic motions consisting of body andsurface waves

I Inelastic (elastic, damage, plastic) behavior of materialsand components: soil, rock, contacts, seismic isolators,concrete, steel, etc.

I Full coupling of pore fluids (in soil and rock and contacts)with soil/rock skeleton

I Uncertainty in seismic sources, path, soil/rock andstructural response

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Motivation

Proposed Solution

I Physics based modeling and simulation (reducemodeling uncertainty) of seismic behavior ofsoil-structure systems (NPP structures, components andsystems)

I Development and use of high fidelity time domain,nonlinear numerical models, in deterministic andprobabilistic spaces

I Accurate following of the flow of seismic energy (inputand dissipation) within soil-structure NPP system

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Motivation

High Fidelity Modeling of Energy Flow

I Energy influx, body and surface waves, 3D, inclinedI Mechanical dissipation outside of SSI domain:

I Radiation of reflected wavesI Radiation of oscillating SSI system

I Mechanical dissipation inside SSI domain:I Plasticity of soil/rock subdomainI Plasticity of foundation – soil/rock interfaceI Viscous coupling of porous solid with pore fluid (air, water)I Plasticity/damage of the structureI Viscous coupling of structure/foundation with fluids

I Numerical energy dissipation/production

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ESSI Simulator System

Outline

Motivation



Current Work

Summary

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ESSI Simulator System

ESSI Project

I Development of the ESSI Simulator System for Hi-Fimodeling and simulation of non-linear earthquake soil/rockstructure interaction problems:

I ESSI-Program is a 3D, nonlinear, time domain, highperformance, parallel finite element program specificallydeveloped for high fidelity modeling and simulation ofEarthquake Soil/Rock Structure Interaction problems forNPPs

I ESSI-ComputerI ESSI-Notes

I A UCD/LBNL project with funding from and collaborationwith the US-NRC, CNSC, US-NSF, US-DOE, LLNL, INL,AREVA NP GmbH, Shimizu Corp. etc.

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Pisanò Model, G/Gmax and Damping Curves

Outline

Motivation



Current Work

Summary

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Pisanò Elastic Plastic Material Model

I 3D incremental elastic-plastic material model that can becalibrated from G/Gmax and damping curve data

I Elasticity: linear or nonlinearI Yield surface, Drucker-Prager cone, collapsed (limit

analysis, vanishing elastic regions) to cylinder (von Mises),with conical bounding surface

I Plastic flow and rotational kinematic hardening, similar toManzari-Dafalias model (1997)

I Yield (loading-unloading) condition established usingstress projection

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Pisanò Model: Calibration for G/Gmax and Damping

10−4

10−3

10−2

10−1

100

1010

0.2

0.4

0.6

0.8

1

γmax

[%]

G/G

max

[−]

10−4

10−3

10−2

10−1

100

1010

0.1

0.2

0.3

0.4

γmax

[%]

ζ [−

]

Seed & Idriss

frict, frict+visc

Seed & Idriss

frict

frict+viscous

Figure: Comparison between experimental and simulated G/Gmaxand damping curves (p0=100 kPa, T=2π s, ζ = 0.003, Gmax = 4 MPa,ν=0.25, M=1.2, kd=ξ=0, h=Gmax /(15p0), m=1)

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Soil Volume Response

I Soil behavior is very much a function of volumetricresponse

I Dilative soils: increase volume due to shearingI Compressive soils: decrease volume due to shearingI Modulus reduction and damping curves do not provide

volumetric dataI Soil volume change will affect response due to volume

constraints

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No Volume Change and Dilative Soil

-20-15-10-5 0 5

10 15 20

-0.02 -0.015 -0.01 -0.005 0 0.005 0.01

τ [k

Pa]

γ [-]

z = H/2

-50-40-30-20-10

0 10 20 30 40 50

-0.035-0.03-0.025-0.02-0.015-0.01-0.005 0 0.005 0.01τ

[kP

a]

γ [-]

z = H/2

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Northridge, No Volume Change and Dilative Soils

-8-6-4-2 0 2 4 6 8

10

0 5 10 15 20 25 30 35 40

Acc

eler

atio

n [m

/s2 ]

Time [s]

no dilatancy vs dilatancy

surf - no dilsurf - dil

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Northridge, No Volume Change and Dilative Soils

0

1

2

3

4

5

6

0 2 4 6 8 10 12 14

Am

plitu

de [m

/s]

Frequency [Hz]

no dilatancy vs dilatancy

basesurf - no dil

surf - dil

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Contact Base Isolation

Outline

Motivation



Current Work

Summary

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Nuclear Power Plant with Base Slip

I Low friction zone betweenconcrete foundation and soil/rock

I Inclined, 3D, body and surface,seismic wave field (wavelets:Ricker, Ormsby; real seismic, etc.)

0 0 2 4 6 8 10 12

Time (s)

0 0 2 4 6 8 10 12

Time (s)

horizontal verticalJeremic




Acc. Response for a Full 3D (at 45◦) Ricker Wavelet

top X

-40

-20

0

20

40

0 1 2 3 4 5 6 7 8

Acc

eler

atio

n (m

/s2)

Time (s)

Slip BehaviorNo-slip Behavior

top Z

-40

-20

0

20

40

0 1 2 3 4 5 6 7 8

Acc

eler

atio

n (m

/s2)

Time (s)


bottom X

-40

-20

0

20

40

0 1 2 3 4 5 6 7 8

Acc

eler

atio

n (m

/s2)

Time (s)


bottom Z

-40

-20

0

20

40

0 1 2 3 4 5 6 7 8A

ccel

erat

ion

(m/s

2)

Time (s)


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Slipping Response and Energy Dissipated (45◦ Ricker)4.5s 4.6s 4.7s

30 40 50 60 70 80 90 100 110

X (m)

30

40

50

60

70

80

90

100

110

Y (

m)

0

0.005

0.01

0.015

0.02

0.025

0.03

30 40 50 60 70 80 90 100 110

X (m)

30

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100

110

Y (

m)

0

0.005

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0.015

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0.025

0.03

30 40 50 60 70 80 90 100 110

X (m)

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Y (

m)

0

0.005

0.01

0.015

0.02

0.025

0.03

4.8s 4.9s 5.0s

30 40 50 60 70 80 90 100 110

X (m)

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110

Y (

m)

0

0.005

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30 40 50 60 70 80 90 100 110

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Y (

m)

0

0.005

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30 40 50 60 70 80 90 100 110

X (m)

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Y (

m)

0

0.005

0.01

0.015

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0.025

0.03

5.1s 5.2s 5.3s

30 40 50 60 70 80 90 100 110

X (m)

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Y (

m)

0

0.005

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0.03

30 40 50 60 70 80 90 100 110

X (m)

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Y (

m)

0

0.005

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0.015

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30 40 50 60 70 80 90 100 110

X (m)

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Y (

m)

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0

500

1000

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2000

2500

3000

3500

0 1 2 3 4 5 6 7 8

Ene

rgy

(kJ)

Time (s)

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Current Work

Current NPP Model(s)I Inclined seismic wavesI Foundation slip/no-slipI Dynamics of impactI Isolators, dissipatorsI Piles and pile groupsI Uncorrelated (incoherent) motionsI Saturated dense vs loose soil with buoyant forces

Surface wave

Body wave

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Summary

SummaryI Nonlinear Earthquake Soil/Rock Structure Interaction

(ESSI) plays a decisive role in seismic performance ofNPPs

I Nonlinear ESSI modeling and simulations has to beperformed using high fidelity modeling and simulation tools

I High fidelity ESSI modeling and simulation tools requireextensive verification and validation

I Risk informed decision making can/should only be doneusing such high fidelity modeling and simulation

I ESSI Simulator Program (system), is one such tool that isused for modeling, simulations, design and regulatorydecision making

I Education and training of users (regulators, designers,owners/applicants) proves essential

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Summary

Acknowledgement

I Funding from and collaboration with the US-NRC, CNSC,US-NSF, US-DOE, LLNL, INL, and collaboration withAREVA NP GmbH, Shimizu Corp., etc. is greatlyappreciated,

I Collaborators, students: Mr. Abell, Mr. Jeong, Mr. Aldridge.Mr. Kamranimoghadam, Dr. Tafazzoli, Dr. Pisanò, Dr.Martinelli, Dr. Preisig, Dr. Chang, Prof. Sett (U. Bufallo),Prof. Taiebat (U. British Columbia), Prof. Yang (U. Alaska)

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essi simulator program, current status

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