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Using torsional bar testing to determine fracture toughness
Author(s) -
Wang J. A.,
Liu K. C.,
McCabe D. E.,
David S. A.
Publication year - 2000
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1046/j.1460-2695.2000.00352.x
Subject(s) - materials science , fracture toughness , composite material , torsion (gastropod) , finite element method , spiral (railway) , ultimate tensile strength , tensile testing , tension (geology) , structural engineering , compact tension specimen , fracture mechanics , crack growth resistance curve , crack closure , engineering , mechanical engineering , medicine , surgery
A new method to determine fracture toughness K IC of materials is introduced. A round‐rod specimen having a V‐grooved spiral line with a 45° pitch is tested under pure torsion. An equibiaxial tensile/compressive stress state is effectively created to simulate conventional test methods using a compact‐type specimen with a thickness equivalent to the full length of the spiral line. K IC values are estimated from the fracture load and crack length with the aid of a three‐dimensional finite element analysis. K IC of 7475‐T7351 aluminium is estimated to be 51.3 MPa √m, which is higher than the vendor’s value in the TL orientation by ∼0.8% and higher than 0.5T compact tension (CT) value by 6%; A302B steel yields 54.9 MPa √m being higher than CT test value by ∼2%. Good agreement between the K IC values obtained by different methods indicates the proposed method is sound and reliable.