Research article

FEM-DBEM approach to analyse crack scenarios in a baffle cooling pipe undergoing heat flux from the plasma

  • Received: 09 December 2016 Accepted: 12 February 2017 Published: 22 February 2017
  • Wendelstein 7-X is the world’s largest nuclear fusion experiment of stellarator type, in which a hydrogen plasma is confined by a magnet field generated with external superconducting coils, allowing the plasma to be heated up to the fusion temperature. The water-cooled Plasma Facing Components (PFC) protect the Plasma Vessel (PV) against radiative and convective heat from the plasma. After the assembly process of heat shields and baffles, several cracks were found in the braze and cooling pipes. Due to heat load cycles occurring during each Operational Phase (OP), thermal stresses are generated in the heat sinks, braze root and cooling pipes, capable to drive fatigue crack-growth and, possibly, a water leak through the pipe thickness. The aim of this study is to assess the most dangerous initial crack configurations in one of the most critical baffles by using numerical models based on a FEM-DBEM approach.

    Citation: R. Citarella, V. Giannella, M. A. Lepore, J. Fellinger. FEM-DBEM approach to analyse crack scenarios in a baffle cooling pipe undergoing heat flux from the plasma[J]. AIMS Materials Science, 2017, 4(2): 391-412. doi: 10.3934/matersci.2017.2.391

    Related Papers:

  • Wendelstein 7-X is the world’s largest nuclear fusion experiment of stellarator type, in which a hydrogen plasma is confined by a magnet field generated with external superconducting coils, allowing the plasma to be heated up to the fusion temperature. The water-cooled Plasma Facing Components (PFC) protect the Plasma Vessel (PV) against radiative and convective heat from the plasma. After the assembly process of heat shields and baffles, several cracks were found in the braze and cooling pipes. Due to heat load cycles occurring during each Operational Phase (OP), thermal stresses are generated in the heat sinks, braze root and cooling pipes, capable to drive fatigue crack-growth and, possibly, a water leak through the pipe thickness. The aim of this study is to assess the most dangerous initial crack configurations in one of the most critical baffles by using numerical models based on a FEM-DBEM approach.


    加载中
    [1] Bykov V (2009) Structural analysis of W7-X: Overview. Fusion Eng Des 84: 215–219. doi: 10.1016/j.fusengdes.2008.12.113
    [2] Corato V, Affinito L, Anemona A, et al. (2015) Detailed design of the large-bore 8T superconducting magnet for the NAFASSY test facility. Supercond Sci Tech 28: 034005. doi: 10.1088/0953-2048/28/3/034005
    [3] Citarella R, Lepore M, Fellinger J, et al. (2013) Coupled FEM-DBEM method to assess crack growth in magnet system of Wendelstein 7-X. Frattura ed Integrità Strutturale 26: 92–103.
    [4] Citarella R, Lepore M, Perrella M, et al. (2016) Coupled FEM-DBEM approach on multiple crack growth in cryogenic magnet system of nuclear fusion experiment 'Wendelstein 7-X'. Fatigue Fract Eng M 39: 1488–1502. doi: 10.1111/ffe.12466
    [5] Citarella R, Cricrì G, Lepore M, et al. (2014) Assessment of Crack Growth from a Cold Worked Hole by Coupled FEM-DBEM Approach. Key Eng Mater 577-578: 669–672.
    [6] Citarella R, Cricrì G, Lepore M, et al. (2014) Thermo-Mechanical Crack Propagation in Aircraft Engine Vane by Coupled FEM-DBEM Approach. Adv Eng Softw 67: 57–69. doi: 10.1016/j.advengsoft.2013.07.006
    [7] Citarella R, Cricrì G (2009) A two-parameter model for crack growth simulation by combined FEM-DBEM approach. Adv Eng Softw 40: 363–377. doi: 10.1016/j.advengsoft.2008.05.001
    [8] Carlone P, Citarella R, Lepore M, et al. (2015) A FEM-DBEM investigation of the influence of process parameters on crack growth in aluminum friction stir welded butt joints. Int J Mater Form 8: 591–599. doi: 10.1007/s12289-014-1186-7
    [9] Citarella R, Cricrì G (2010) Comparison of DBEM and FEM Crack Path Predictions in a notched Shaft under Torsion. Eng Fract Mech 77: 1730–1749. doi: 10.1016/j.engfracmech.2010.03.012
    [10] Citarella R, Cricrì G, Lepore M, et al. (2010) DBEM and FEM Analysis of an Extrusion Press Fatigue Failure. In: Öchsner A, Da Silva LFM, Altenbach H, Materials with Complex Behaviour-Advanced Structured Materials, Springer-Verlag, Berlin, Germany, 3: 181–191.
    [11] Citarella R, Buchholz FG (2008) Comparison of crack growth simulation by DBEM and FEM for SEN-specimens undergoing torsion or bending loading. Eng Fract Mech 75: 489–509. doi: 10.1016/j.engfracmech.2007.03.039
    [12] Dassault Systèmes Simulia Corp. (2011) Abaqus Analysis User's Manual, Version 6.12.1, Providence, RI, USA.
    [13] BEASY (2011) BEASY V10r14 Documentation, C.M. BEASY Ltd.
    [14] Rigby RH, Aliabadi MH (1993) Mixed-mode J-integral method for analysis of 3D fracture problems using BEM. Eng Anal Bound Elem 11: 239–256. doi: 10.1016/0955-7997(93)90026-H
    [15] Rigby RH, Aliabadi MH (1998) Decomposition of the mixed-mode J-integral-revisited. Int J Solids Struct 35: 2073–2099. doi: 10.1016/S0020-7683(97)00171-6
    [16] Portela A, Aliabadi MH, Rooke DP (1991) The dual boundary element method: effective implementation for crack problems. Int J Numer Meth Eng 33: 1269–1287.
    [17] EI Haddad MH, Smith KN, Topper T (1979) Fatigue crack propagation of short cracks. J Eng Mater Techn-T ASME 101: 42–46. doi: 10.1115/1.3443647
    [18] Simonovski I, Nilsson KF, Cizelj L (2007) Crack tip displacements of microstructurally small cracks in 316L steel and their dependence on crystallographic orientations of grains. Fatigue Fract Eng M 30: 1–10. doi: 10.1111/j.1460-2695.2006.01092.x
    [19] Benedetti I, Aliabadi MH, Davì G (2008) A fast 3D dual boundary element method based on hierarchical matrices. Int J Solids Struct 45: 2355–2376. doi: 10.1016/j.ijsolstr.2007.11.018
  • Reader Comments
  • © 2017 the Author(s), licensee AIMS Press. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0)
通讯作者: 陈斌, bchen63@163.com
  • 1. 

    沈阳化工大学材料科学与工程学院 沈阳 110142

  1. 本站搜索
  2. 百度学术搜索
  3. 万方数据库搜索
  4. CNKI搜索

Metrics

Article views(4480) PDF downloads(915) Cited by(8)

Article outline

Figures and Tables

Figures(26)  /  Tables(3)

/

DownLoad:  Full-Size Img  PowerPoint
Return
Return

Catalog