Plastic eta factor solutions of homogeneous and bi-material SE(T) specimens for toughness and creep crack growth testing

Based on slip line field analysis and finite element analysis of elastic-pe rfectly plastic materials, plastic eta factor solutions for single edge-cra cked specimens in tension (SE(T)) with a wide range of crack lengths are pr oposed, both for homogeneous specimens and for bi-material specimens with i nterface cracks. Moreover, two different plastic eta factor solutions are g iven: one based on experimental load-load line displacement records, eta (V LL)(p), and the other based on experimental load-crack mouth opening displa cement (CMOD) records, eta (CMOD)(p). Comparison with existing finite eleme nt results shows good agreement. For deep cracks (a/w > similar to 0.45), t he eta (VLL)(p) solutions are insensitive to the strain hardening, to the s pecimen length and to the specimen thickness. However, for shallower cracks (a/w, < <similar to>0.45), the eta (VLL)(p) solutions are sensitive to the specimen thickness, to the strain hardening and to the specimen length, su ggesting difficulties associated with a robust determination of F and C* in tegrals from experimental data. On the other hand, the eta (CMOD)(p) soluti on is not sensitive to the crack length, to the specimen thickness, to stra in hardening and to the specimen length, even for shallow cracked specimens . This suggests that the use of CMOD can provide robust F and C* estimation schemes even for shallow crack testing.