simulation model for sg eddy current sg inspection...simulation model for sg eddy current sg...

Nondestructive Evaluation Laboratory

35th Annual EPRI Steam Generator NDE Workshop, Clearwater Beach, Florida July 2016

Simulation Model

for SG Eddy Current SG Inspection

Saptarshi Mukherji, Anton Efremov, Pavel Roy, Portia Banerjee, Anders Rosell, L.Udpa


Michigan State University

&

Rick Williams, Nathan Driessen, James Benson

EPRI


Outline

Benefits/Motivation

Applications of Simulation Model

Objectives

Summary of SGTSIM Features

Simulation Results

Current Ongoing work

Conclusions and Future Work

2


Benefits of Simulation Models

What can simulation models do?

Predict EC probe signals for different defect geometry

Test bed for generating defect signatures

Effect of probe wobble, frequency, sludge characteristics on probe measurements

Training tool

Optimization of sensor/system design

Useful in Probability of Detection (POD) Models at low cost

Use in Reverse engineering models for finding root cause of complex signals

Key Advantages of Simulation Model:

Provides an inexpensive and fast method to simulate realistic defect geometries

3


Practical Applications of Simulator Software

• Utility Engineers

‒ Assist in complex signal interpretation & Tube Integrity Assessments

‒ Assist in POD calculations

Inspection vendors

Assist in signal interpretation

Assist in SSPD development

• Probe developers

Aid in probe design

• NDE instructors

Training tool

Generate signals for training data

• Researchers / Qualifying Institute

Generate signals for probe technique qualification (ETSS’s)

Generate signals for performance demonstration (QDA/AAPDD)

4


Continue development of a software tool that is capable of accurately simulating signals representing SG EC inspection data from various: Tube degradation mechanisms

SG tube geometries

Eddy current coil configurations

Sludge compositions

Foreign objects

Generate simulated EC signals in a format that is representative of signals generated by field SG eddy current test equipment. Simulated data will be formatted so that it can be read and

processed by commercial data analysis software

Project Objectives

5


SGTSIM v4.0 (Beta) Features -Summary

Probes

Bobbin

Pancake (.115)

X-Probe .610 Tube Geometry

Support

Plate

Tube

Sheet

Free

Span

Defect Geometry

Location Freespan

TSP

TTS

ID/OD

Orientation Circ

Axial

Shape Circular

Elliptical

Rectangular

Real Cracks

Other features:

Data Export in MIZ Format

Batch Processing

Generate noise added signal

All results are experimentally validated

+ Point

MRPC

TSP TTS Free span

Bobbin probes - (0.510 TF, 0.560 TF, 0.560

HF, .610 MR, 0.610 TF, 0.610 HF, 0.350 MR,

0.380 MR, 0.480 MR, 0.540 TF, 0.710 MR,

0.720 MR)

6

Choose defect type as

“Real Crack”

Choose Defect orientation as

“ID” or “OD”

Example of User Interface Window Data Input screen

7

Axial Notch - ID Axial Notch - OD

Circumferential Notch - ID Circumferential Notch - OD

GUI for Real Cracks

Axial Notch - ID

8


Using SGTSIM batch export feature, multi-frequency and multi-coil data can be generated and combined into a multi-channel data file in csv format

This csv file can be used to generate a corresponding MIZ-80 datafile by the ‘C2D converter’ from Zetec, and viewed in Eddynet display.

Develop export modules for multichannel probe

configurations

Generated

MIZ-80 Data

File Channel configuration

User selected files

CSV file Generator

Process & Other

Header Information

.csv file Simulated

signals

C2D

Converter

9


Position Depth (%) Defect

Type Probe Frequency (Khz)

O.D./I.D. 100,60,40 Axial

.610 X-Probe 400, 300, 100, 50 Circ

O.D./I.D. 100,60,40 Axial

.610 TF Bobbin 550, 280, 140, 35 Circ

O.D. 100,60,40, 20(4) FBH .610 TF Bobbin 550, 280, 140, 35

O.D. 100,60,40, 20(4) FBH .560 HF Bobbin 650, 320, 170, 35

O.D. 100,60,40, 20(4) FBH .510 TF Bobbin 750, 380, 200, 50

O.D./I.D. 100, 60, 40, 20

Axial Rotating +Pt

(PP11A) 300, 200, 100, 35

Circ Rotating

Pancake (P115A)

n/a Radial exp

(0.016”)

360 deg

Expansion .610 X-Probe 400,300,100,50

Calibration Flaw Simulations – in Progress

Position Depth (%) Defect Type Probe Frequency

(Khz)

O.D. 30 Groove .610 X-Probe 400,300,100,50

Validation of SGTSIM • Database of simulated calibration standard flaws eddy current signals

10


Exported Bobbin Signals displayed in Eddynet

Experimental Data

750kHz 380kHz 200kHz 50kHz 750kHz 380kHz 200kHz 50kHz

40% Circular Flaw- Diff channels

Simulated Data

380kHz 200kHz

11


100% Axial Flaw

Exported 0.610 Array Signals displayed in Eddynet

Experimental Data Simulated Data

400kHz 400kHz 140kHz 140kHz

12


Exported MRPC Signal displayed in Eddynet

080 PAN 115 PAN +Pt

115

PAN

115

PAN

+ Pt + Pt

Simulated Data Experimental Data 40% O.D. Axial Flaw

115 PAN +Pt

13


Capability to Read Crack Profile from Excel File

Axial Notch Profile from

MET data - mesh

+Point Probe ; 300KHz ; FARLEY-1 # 25-51

Simulated Signals Experimental Signals

Profile Table

Length (mm) % TW

-6.7056 0

-5.8674 17

-5.0292 17

-4.191 38

-3.3528 67

-2.5146 67

-1.6764 77

-0.8382 73

0 62

0.8382 57

1.6764 57

2.5146 60

3.3528 28

4.191 22

5.0292 22

5.8674 20

6.7056 23

6.7564 0

14

Quantitative Metrics

Flaw size Coil type Magnitude Difference

(%)

Phase Difference

(º)

Axial notch Depth 100%

Length 0.38’’ Width 0.005

RPC +Point 0.6 1.6

RPC Pancake 2.9 1.7

Axial notch Depth 57% OD

Length 0.38’’ Width 0.005’’

RPC +Point 1.1 0.9

RPC Pancake 3.9 1.8

100% TW Circular hole X Probe

Axial

0.9 0

X Probe

Circumferential

1.4 0

100% TW hole .610 Bobbin probe

6.1 0.5

SG Exam Guidelines Data Quality Acceptance Criteria:

• Phase changes on normalized reference signal ±5°

• Amplitude changes on normalized reference signal ±20%

15


Current Ongoing work

1. Setup SGTSIM to run in EPRI HPC

• Linux based SGTSIM developed for testing HPC

implementation

• Linux version installation at EPRI HPC

2. Training dataset- Signals generated where experimental data is

unavailable in ETSS dataset

3. Reverse engineering - determine root cause of complex field

signal

4. Noise incorporation in simulated signals for POD analysis

5. Simulation of :

Loose parts (Carbon steel, Stainless steel, Copper)

Complex signals

16


1. Development of a new SGTSIM GUI • Cross- platform (Windows and Linux)

• Modular structure (Easy to extend the functionalities)

• Unified control over the Local and Remote machines

17


2. SGTSIM for Training data generation

Flaw shape: Rectangular, Crack Width:0.005'',

Tube OD:0.75'',Tube wall Thickness:0.043

Position Length depth Frequency Orientation Probe

50 100 200 300 400 Axial Circ Pancake +Pt

OD

0.3’’

20 √ √ √ √ √ √ √ √ √

40 √ √ √ √ √ √ √ √ √

ID 40 √ √ √ √ √ √ √ √ √

20 √ √ √ √ √ √ √ √ √

OD 0.5’’

20 √ √ √ √ √ √ √ √

40 √ √ √ √ √ √ √ √

100 √ √ √ √ √ √ √ √

√: finished

Flaw shape: Rectangular ,Crack Length:0.5'',Crack Width:0.005'', Tube OD:0.875'',Tube wall Thickness:0.052

Position depth Frequency Orientation Probe

15 100 200 300 Axial Circ pancake +Pt

ID 39 √ √ √ √ √ √ √

√: finished

Flaw shape: FBH of diameter:0.05'', Tube OD:0.875'',Tube wall Thickness:0.052

depth Frequency Probe

15 100 200 300 pancake +Pt

100 √ √ √ √ √ √

√: finished

18


3. Use of SGTSIM for Reverse Engineering of Complex Field Signals

A 150 kHz +Pt Mag Bias coil showing volumetric indication of 0.09 Volts was

observed 0.2 inch above the hot leg TTS in a one inch sludge collar

• Complex Field Data

ECT Graphics of 400 kHz +Pt coil w/ volumetric indication

19

Possible causes

Loose part wear in the sludge pile region

Pitting

Hard sludge collars with a small area where sludge deposits have

flaked off

Lap signals

Develop mesh for each test

case

ECT Simulations of test cases using

SGTSIM

Comparison of calibrated simulated

signals vs

Experimental signals for closest match

Determine possible cause of field data

Reverse Engineering Algorithm


20

Case I. Loose part wear in the sludge pile region

Sludge Sludge

Sludge

Tube Tube

Defe

ct

Mesh of the Geometry

Zoom

ed in

Sludge Properties: Permeability: 7, Conductivity: 0

Defect Dimensions:12 % TW 0.2” length, 0.005” width


21

Liz Plot

shows

defect

indication

Field data

Initial results

Simulation results


22


• 1 D Random noise

Horizontal and vertical components of the signal are affected by noise

independently.

Variance of noise is changed to control power of the injected noise.

Noise variance = 0.152

Noise variance = 0.352

Noise Free SGTSIM

simulated bobbin

signal for 80%

through-wall OD

defect near TSP

Noise added to Hor. Com. Noise added to Vert. Com.

Noisy signal

4. Capability to Inject Simulated Noise into Simulated Signal

23


Experimental field data AAPDD, + point probe

100KHz, Horizontal channel

ANO Defect

GUI for controlled Noise injected simulated data

+ point probe, 100KHz, Horizontal channel

User selected noise

parameters

Simulated Defect

4. Capability to Inject Simulated Noise into the

Simulated Signal – 2D Random & Periodic noise

24


= + +

Simulation flaw signal

Random noise

Zero-mean additive

Gaussian noise Periodic noise Simulation signal with noise



Simulation flaw signal

Random noise

Zero-mean additive

Gaussian noise Periodic noise Simulation signal with noise



25


Summary/Conclusions

A computational model for simulating SG tube inspection has been

developed and validated using experimental measurements

Experimental validation of Simulation results from a variety of probe

geometry, tube geometry and defect geometry has been presented

The model has several potential applications -

The model can be used as test-bed to generate signals from defects that are

expensive to fabricate

The model allows user to make controlled variations of material properties, defect

profiles and other operational parameters and observe effect of these changes on

the measured signal (useful in POD calculations)

The model can be used as a reverse engineering tool for determining root cause

of complex signals

26


Future work 2017

• Develop capability to produce array probe signals from each of

the individual array coils

• Develop EC signal simulation capability for: • Simulation of AVBs and lattice grid geometries.

• A shielded rotating 0.080” pancake coil probe

• Demonstrate use of SGTSIM for MAPOD applications

2018

• Develop EC signal simulation capability for: • Tube U-bend region

• Wear flaws and cracks in U-bend region

• Broached tube supports

• Develop SGTSIM Solver for faster performance

• Release SGTSIM Ver 5.0

27


Thank You

Questions?

28

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