Simulation of ultrasonic guided wave inspection

in CIVA software platform

B. CHAPUIS, K. JEZZINE, V. BARONIAN, D. SEGUR and A. LHEMERY

18 April 2012

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CIVA: Software for NDT Generalities

WHY USING SIMULATION IN NDT?

Design of new methods and probes (e.g. phased arrays)

Qualification of methods, performance demonstration

Interpretation of complex results, diagnosis

« Virtual testing » in product design phases

Training

CIVA: SIMULATION FOR NDT

Multi-technique platform: UT, ET, RT-CT… Guided Waves

Experimental validation within international benchmarks

ET : 2D map of a complex defect

UT : Transmitted beam computation

RT : weld inspection

Developed by 4 labs at CEA-LIST ~ 25 permanent developers

CT : tomographic reconstruction

of complex parts

Simulation of GW in CIVA

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CIVA: Software for NDT Generalities

SEMI-ANALYTICAL MODELS

Based on simplified hypothesis and/or approximations

Numerical performances (fast computations) and easy to use

Accurate and reliable (validated) predictions for a wide range of situations

Possible intensive use in an industrial environment

Possible coupling with purely numerical approaches (FDTD, FEM…)

IMPLEMENTATION OF A CIVA SOFTWARE PLATFORM

A unique set of NDT oriented GUIs, for all techniques

Connection to CAD tools

In the same environment: Simulation, imaging and processing tools

Simulation of GW in CIVA

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Functionalities of CIVA GW 10

Mode computation

Field computation

Defect response

Current developments

2D CAD waveguides

Arbitrary defects

OUTLINE

Simulation of GW in CIVA

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First version of CIVA GW Different modules

THREE MODULES

• Mode computation

• Display of dispersion curves (phase/group velocity & attenuation)

• Display of displacement/stress profile in the cross-section

• Information on the modes possibly propagating in the guide

• Field computation • Visualization of displacement/stress field emitted by a transducer

• Display of dispersion curves in the bandwidth of the transducer

• Display of the modal amplitude generated by the transducer

• Applications: mode selection, design of sensors

• Defect response (restricted to normal cracks) • Display of Ascan

• Display of dispersion curves in the bandwidth of the transducer

• Display of the modal amplitude generated/detected by the transducer and diffracted by the defect

• Response of a crack to one or several modes

Simulation of GW in CIVA

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First version of CIVA GW Functionalities

Specimens • plates (2D computation: Lamb/SH wave)

• pipes/cylinders (2D and 3D computation)

• multilayered (no immersed or embedded guides)

• no arbitrary 2D CAD cross-section (ex: rail)

Materials

• isotropic solid

• attenuation law: linear with frequency

Transducers • contact with or without wedge

• encircling/encircled probes (phased arrays)

• different type of solicitations

• pulse-echo/pitch catch configurations

Flaws

• cracks orthogonal to the guide axis

Simulation of GW in CIVA

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Functionalities of CIVA GW 10

Mode computation

Field computation

Defect response

Current developments

2D CAD waveguides

Arbitrary defects

OUTLINE

Simulation of GW in CIVA

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Modes of a pipe : influence of coating Geometry and frequency range

½ mm viscoelastic coating

(protective layer)

Simulation of GW in CIVA

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Modes of a pipe : influence of coating Material parameters

viscoelastic coating

steel pipe

Simulation of GW in CIVA

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Modes of a pipe : influence of coating Dispersion curves

with coating

without coating

Simulation of GW in CIVA

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Modes of a pipe : influence of coating Dispersion curves

with coating

without coating

ur

At 100 kHz

with coating :

Ve = 2.996 mm/µs

Att = 0.206 dB/m

without coating

Ve = 3.011 mm/µs

Att = 0 dB/m

Simulation of GW in CIVA

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Modes of a pipe : influence of coating Dispersion curves

with coating

without coating

Torsional mode

propagating in

the coating

u

Simulation of GW in CIVA

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Functionalities of CIVA GW 10

Mode computation

Field computation

Defect response

Current developments

2D CAD waveguides

Arbitrary defects

OUTLINE

Simulation of GW in CIVA

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Field computation Generation of Lamb modes with a wedge transducer

Civa simulation

Experimental measurement by Terrien

Configuration

N. Terrien, D. Osmont, D. Royer, F. Lepoutre and A. Déom, ‘A combined finite element and modal decomposition method to study the

interaction of Lamb modes with micro-defects’, Ultrasonics, 2007

Simulation of GW in CIVA

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Field computation Phased array capabilities

Multi-element probe and associated

delay (and amplitude) laws

1.5 m

Section on which the

field is computed

Manual definition of the laws

Simulation of GW in CIVA

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Field computation Visualization of the focusing in the pipe

Multi-element probe and associated

delay (and amplitude) laws

1.5 m

Section on which the

field is computed

Uy axial component

Simulation of GW in CIVA

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Functionalities of CIVA GW 10

Mode computation

Field computation

Defect response

Current developments

2D CAD waveguides

Arbitrary defects

Simulation of GW in CIVA

OUTLINE

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Defect response computation Sectorial ring in a pipe

The defect is perpendicular to the waveguide axis

Simulation of GW in CIVA

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Defect response Focusing

Multi-element probe and associated delay

(and amplitude) laws

1.5 m

Defect located at different

angular positions in this section

Simulation of GW in CIVA

Defect response

amplitude -25

-20

-15

-10

-5

00

45

90

135

180

225

270

315

Field emitted

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Defect response Example of validation results

Emission:

• 2 encircling probes (length 20 mm, spacing 50 mm)

• Axial excitation (6 cycles toneburst at 100 kHz)

Reception:

• Small PZT

Axisymmetric notch of variable thickness

Tang Li-Guo, Mechanism of the excitation of single pure mode L(0,2) and its interaction with the defect in a hollow cylinder, Chinese

Physics, 2007

Simulation of GW in CIVA

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Defect response Example of validation results

Very good agreement of

the mode conversions

Simulation of GW in CIVA

defect height/pipe thickness ratio

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Functionalities of CIVA GW 10

Mode computation

Field computation

Defect response

Current developments

2D CAD waveguides

Arbitrary defects

OUTLINE

Simulation of GW in CIVA

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Current integration into Civa GW Propagation in arbitrary 2D CAD waveguides

Example of mode computation in a rail

Width: 152 mm

Height: 172 mm

Material: steel

ux uy uz

Simulation of GW in CIVA

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Current integration into Civa GW Arbitrary defects

2D

3D

Inclusion in a cylindrical rod Crack in the head of a rail

Based on an efficient SAFE / FE hybrid model: FE computation of defect scattering hybridised with SAFE

computation through specific modal transparent boundaries

Baronian et al., J. Comp. Appl. Math., 2010

Coupling with a finite element formulation for defect scattering

Simulation of GW in CIVA

FE Box

Transparent

boundaries

corrosion pitting

Semi-analytical generation,

propagation and detection

scattering

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Conclusion

THREE MODULES

• Mode computation

• Field computation

• Defect response (restricted to normal cracks)

CURRENT DEVELOPMENTS

• 2D CAD waveguides

• Arbitrary defects

• Anisotropic materials

• Generation by EMAT (coupling with ET module)

Simulation of GW in CIVA

Available in CIVA GW 10

a) b)

90°

0°180°

270°

0.5

1.0

1.5c) (S.cT)

Slowness curves in

composite plate

Generation of SH0 mode with an EMAT

FE Box

Transparent

boundaries

corrosion pitting

Semi-analytical generation,

propagation and detection

scattering

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Thank you for your attention !

Simulation of GW in CIVA