Eta plastic correlation to evaluate crack tip opening displacement of pre-cracked small punch test specimen using experimental data

A new.LLD d,pl correlation is proposed to evaluate the plastic component of crack tip opening displacement (dplastic) of a pre-cracked small punch test (known as p-SPT) specimen by using load (P) versus load line displacement o.THORN experimental data. Through thickness pre-cracked square-shaped specimens are modeled for this purpose. The three crack sizes oa=WTHORN considered for the present study are 0.40, 0.45, and 0.50. The elastic-plastic finite element simulations are performed to compute (P) data by varying Ramberg-Osgood hardening exponents as 5, 10, 15, and 20. In addition, one elastic perfectly plastic material behavior is also considered. After that, the FE data are used to calculate (a) CTOD (dplastic) and (b) the plastic component of area under the (P.) curves, that is, Aplastic. The proposed correlation of.LLD d,pl for p-SPT specimens as function of effective crack size a'= Wo 0THORN is then derived by plotting a best-fit straight line over the data between dplastic and Aplastic in nondimensional form. The usefulness of the proposed correlation is then demonstrated by applying the same to experimental data of p-SPT specimens.