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GA 1 - 2 - 3 - 4 - AP 1 - 2 - 3 - 4 - 5 - NT 1 - 2 - 3 - 4 - 5 - 6Vol.1No.2
Vol.1, No.1, NT1 EJAM(1-1-NT1) - Simulation Technique for UT Wave Propagation as an Effective Tool for Predicting the Inspection Results and Interpreting the Root Cause of Unexpected Indications

Simulation Technique for UT Wave Propagation as an Effective Tool for Predicting the Inspection Results and Interpreting the Root Cause of Unexpected Indications

Ichiro KOMURA 1 and Takashi FURUKAWA 2
1Nondestructive Evaluation Center
2Japan Power Engineering and Inspection Corporation

UT inspection, Wave propagation, 2D & 3D modeling, FEM analysis code, Prediction of inspection results, Training tool

1. Technical summary
(I: Inspection, II: Repair, III: Replacement, IV: Preventive Maintenance, V: Others)
  • Technical field : NDE technique
  • In case of UT inspection on structural component, especially on weld and complicated geometry, the miss calling/false calling of indication and the deterioration of depth sizing performance has occurred.
  • In order to improve these phenomena, large scale FEM modeling technique for simulating the ultrasonic wave propagation has been developed and used to predict the results of UT inspection which has affected by the attenuation/dispersion/distortion of wave and the change of wave propagating direction and path, etc..


Fig. 1 Factors which affect to the UT wave propagation(1),(2)

2. Scope
  • Two dimensional modeling (example : plate inspection)
  • Three dimensional modeling like a circumferential inspection on dissimilar metal weld and a J-weld of penetration tube
  • Homogeneous materials and inhomogeneous/anisotropic materials of a weld or buttering
  • Calculation of wave propagation behavior
    → Wave propagation movie
    → Detected waveform(A-scope)
    → B-scope imaging by mechanical probe scanning and phased array beam scanning



Fig. 2 Wave propagation behavior of the plate inside inspection

Fig. 3 3D modeling of DMW with weld and buttering

3. Features
  • Prediction of UT inspection results, position and amplitude of indication in A-scope described in the figure as an example of depth evaluation by mode conversion method
  • Optimization of UT inspection condition or parameters, such as the time delay setting for phased array inspection
  • Analysis of root cause of unexpected inspection results, such as miss calling/false calling and deterioration of depth sizing performance
  • Education and training of inspection personnel
  • Scientific and technical research for ultrasonic and elastic wave propagation



Fig.4 Mode converted wave in the case of shallow crack(3)

Fig.5 Mode converted wave in the case of deep crack(3)

4. Examples of Application
  • Mockup experiment on the nozzle safe end dissimilar metal weld were carried out prior to the plant ISI using longitudinal wave probe and automatic inspection system.
  • Many indications were detected in the no flaw test block.
  • As the result of simulation analysis, same B-scope image are obtained.
  • The root causes of many indications were made clear by the detailed observation of wave propagation movie.
  • These results and technique have been used practically in the actual ISI of nuclear power plants.



Fig. 6 B-scope image of inspection result on realistic test block(4)

Fig. 7 B-scope image obtained by wave propagation simulation(4)


Fig. 8 Example for root cause investigation of indications(4)

5. Reference
  1. I. Komura, Y. Ikegami, H. Nakamura, M. Igeta, Numerical Analysis of Elastic Wave Propagation in Simulation of Ultrasonic Examination, Proceedings of 1st International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components, JRC, Amsterdam, October 20-22, 1998, pp.967-972.
  2. I. Komura, H. Nakamura, H. Miharada, N. Uesugi, Development of High Resolution and Large Scale FEM Analysis Code for The Simulation of UT Examination on Stainless Steel Weldment, Proceedings of 2nd International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components, JRC, New Orleans, May 24-26, 2000, B221-B231.
  3. T. Furukawa, I. Komura, Evaluation for Crack Depth Sizing Capabilities of Improved UT Techniques by Numerical Simulation of Wave Propagation, Proceedings of 30th MPA-Seminar in conjunction with the 9th German-Japanese Seminar, MPA, Stuttgart, October 6-7, 2004, pp.51.1-51.13
  4. I. Komura, T. Furukawa, T. Kamada, Y. Minami, Evaluation of UT simulation Software and Examples of It's Application, Proceedings of 4th Annual Meeting, JSM, Fukui, 2007, pp.245-248 (written in Japanese)
  5. I. Komura, T. Furukawa, Recent Progress of UT Inspection Technique on Piping Weld and the Role of Wave Propagation Modeling, Proceedings of the International Symposium on Research for Aging Management of Light Water Reactors, Oct, 22-23, 2007, Fukui City, JAPAN, pp.429-439
6. Contact
Japan Society of Maintenology (