Evaluation of fracture mechanics parameters for bimaterial compact tension specimens. (August 2013)

• Record Type: Journal Article
• Authors: Zhou, H.; Mehmanparast, A.; Davies, C. M.; Nikbin, K. M.
• Is Part Of: Materials research innovations. Volume 17:Number 5(2013)
• Page Start: 318
• Page End: 322
• Publication Date: 2013-08
• Subjects: Eta factor, -- J parameter, -- Weld mismatch, -- Finite element, -- Compact tension; Materials -- Research -- Periodicals; Matériaux -- Recherche -- Périodiques; 620.1105
• DOI: 10.1179/1433075X13Y.0000000142
• Languages: English
• ISSNs: 1432-8917

Abstract

Abstract : 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 η factor. For weldments, the η 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 2 h, 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.