Extended Investigation of Test Specimen Thickness (TST) Effect on the Fracture Toughness (Jc) of a Material in The Transition Temperature Region as a Difference in the Crack Tip Constraint–what is a loss in Constraint in the TST Effect on Jc?

摘要: Abstract This paper is an extension of our recent work (Meshii et al., 2013), which demonstrated through experiments and elastic-plastic (EP) finite element analysis (FEA) that the test specimen thickness (TST) effect on fracture toughness a material J c in ductile-to-brittle transition temperature region, together with bounded nature for large TST, had correlation out-of-plane constraint parameter T 33-stress. Because definite measure crack tip magnitude, especially EP issues, does not exist, several well-known parameters were tested from standpoint whether they have correlations to decreasing then increasing TST. The results clearly indicated z = σ 33 /( 11+ 22) at mid-plane could be directly correlated TST c, based observation highest did coincide location predicted by (4 δ t, 22c) criterion, 22c denotes critical opening stress value distance ahead equal four times displacement t . On other hand, Θ (hydrostatic stress)/(von Mises stress), measured 4 , has ability monitor loss c. linear relationship 22 up load P thick specimens thickness-to-width ratio B / W 1.0 1.5, while thin 0.25 0.5 began decrease before reaching In addition, exhibited good