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Róbert Beleznai Tibor Köves Péter Kavalyecz

BAY - LOGI. 2 nd Hungarian-Ukrainian Joint Conference on SAFETY-RELIABILITY AND RISK OF ENGINEERING PLANTS AND COMPONENTS ASSESSMENT OF SUB-CLAD FLAWS, J-INTEGRAL CALCULATION. Róbert Beleznai Tibor Köves Péter Kavalyecz. Bay Zoltán Foundation for Applied Research

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Róbert Beleznai Tibor Köves Péter Kavalyecz

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  1. BAY-LOGI 2nd Hungarian-Ukrainian Joint Conferenceon SAFETY-RELIABILITY AND RISK OF ENGINEERING PLANTS AND COMPONENTSASSESSMENT OF SUB-CLAD FLAWS, J-INTEGRAL CALCULATION Róbert Beleznai Tibor Köves Péter Kavalyecz Bay Zoltán Foundation for Applied Research Institute for Logistic and Production Systems Kyiv 20th September, 2007

  2. BAY-LOGI CONTENT • Test specimens • Crack type • Crack dimensions • Crack geometry • Material properties • Residual stress • Validation of the model • Boundary condition • J-integral calculation 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  3. BAY-LOGI Introduction Main objective of the work • WWER Cladded Reactor Pressure Vessel (WWER-440)J-integral calculation based on the report of the Nuclear Research Institute Rez plc, Division of Integrity and Technical Engineering. 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  4. BAY-LOGI Test specimen • Specimen type: 4PB(40x85x670 mm) 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  5. BAY-LOGI Material properties • WWER reactor pressure vessel steel with austenitic cladding • Data arises from the report of the NRI • True stress – true plastic strain curve was derived for the FE calculation 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  6. BAY-LOGI Material properties Poisson ratio: =0.3 E=162 GPa =17.1*10-6 E=211 GPa =12.55*10-6 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  7. BAY-LOGI Crack types • Two different crack lengths were analyzed • 1e2 and 1e4: • crack length: 15 mm • upper cracktip located 3 mm under the fusion line of the cladding • both crack tips are sharp • 1e7: • crack length: 40 mm • upper cracktip located 3 mm under the fusion line of the cladding • upper crack tip is sharp • lower crack tip is drilled out 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  8. BAY-LOGI Crack dimensions Straight crack front were considered in all case. 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  9. BAY-LOGI Crack geometry 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  10. BAY-LOGI Residual stress • Residual stress arises from the difference of the thermal expansion coefficients • Stress free temperature: Tsf=350°C 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  11. BAY-LOGI Residual stress Comp 11 of stress 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  12. BAY-LOGI Residual stress 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  13. BAY-LOGI Validation of the FE model 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  14. BAY-LOGI NRI BZF The results of NRI and BZF are in very good correlation. 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  15. BAY-LOGI Load-displacement curves 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  16. BAY-LOGI FE model • MSC.MARC 2005R3 code • 3D model • 20 nodes hexahedron elements • J-integral calculation 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  17. BAY-LOGI Boundary conditions Only one quarter of the specimen was simulated. Symmetry condition Total applied force 2 Total applied force 2 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  18. Straight crack front BAY-LOGI J-integral calculation J-integral values along the crack front at max loading 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  19. Straight crack front BAY-LOGI J-integral calculation J-integral valueshistory plot 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  20. 1E7 1E4 1E2 BAY-LOGI Real crack front 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  21. Real crack front BAY-LOGI J-integral along the crack front 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  22. Real crack front BAY-LOGI J-integral history plot J-integral valueshistory plot 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  23. BAY-LOGI Conclusion • In case of short straight and short real cracks the difference of the J-integral values is not significant. • In case of deep crack more accurate J-integral value was resulted, if real crack front was modelled. • Residual stress was considered, and this calculation is validated by NRI data. • FE models were also validated by LLD curve of NRI. 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  24. BAY-LOGI Possibilities for further investigations • Weibull stress calculation based on the Beremin-model. • T-stress calculation. 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

  25. BAY-LOGI Thank you for your kind attention! 2nd Hungarian-Ukrainian Joint Conference – Kyiv, 2007

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