Evaluation of fracture mechanics parameters for bimaterial compact tension specimens

H. Zhou, A. Mehmanparast, C. M. Davies, K. M. Nikbin

Research output: Contribution to journalArticlepeer-review


The elastic–plastic fracture mechanics parameter J and its analogous creep fracture parameter C* are widely used to measure the fracture resistance of a material. The non-linear component of the J and C* parameters can be evaluated experimentally using the g factor. For weldments, the g factor is dependent on the relative properties of the base (parent) and weld materials, particularly the mismatch in their yield strengths. In this work, the η factor has been evaluated using non-linear finite element analyses in a standard compact tension C(T) specimen for a power law material. A range of mismatches in base/weld material properties have been considered. A through thickness strip of weld material, of height 2h, has been modelled, which was positioned at the mid height of the specimen. The η factor has been evaluated for a range of crack lengths and power law hardening exponents under both plane stress and plane strain conditions and the results compared with literature where available. For a given crack length and weld width, the η solutions of the undermatched and overmatched conditions examined show a maximum variation of 12% from the mean value. A relationship has been proposed with respect to crack length for the C(T) specimen to describe the decrease in the η factor with an increase in mismatch ratio.

Original languageEnglish
Pages (from-to)318-322
Number of pages5
JournalEnergy Materials: Materials Science and Engineering for Energy Systems
Issue number5
Publication statusPublished - 22 Oct 2013


  • compact tension
  • Eta factor
  • finite element
  • J parameter
  • weld mismatch


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