Proposal of the hybrid solution to determining the selected fracture parameters for SEN(B) specimens dominated by plane strain

Abstract

In the paper, new hybrid (numerical-analytical) methods to calculate the J-integral, the CTOD, and the load line displacement are presented. The proposed solutions are based on FEM calculations which were done for SEN(B) specimens dominated by plane strain condition. The paper includes the verification of the existing limit load solution for SEN(B) specimen with proposal of the new analytical formulae, which were used for building hybrid equations for determining three selected fracture mechanics parameters.

A Numerical Analysis of Selected Elastic-Plastic Fracture Parameters for DEN(T) Plates under Plane Strain Conditions

“…However, in the case of the load line displacement v LL , the opposite situation is observed; the obvious conclusion is that the shorter the crack, the higher the values of the load line displacement v LL at the same level of the normalized external load P/P 0 (Fig.22c). The similar conclusions shown in [31]. …”

“…In his earlier studies [20], the author indicates that the values of the functions h 1 , h 2 , and h 3 change with a variation of the external load. The similar conclusions shown in [31]. It is quite interesting to note that the functions h 1 * , h 2 * and h 3 * are not dependent on the yield strength (Fig.27a).…”

“…It can be noted that for the case when the external load is equal to or greater than the limit load, P 0 , the h 1 * =f(P/P 0 ), h 2 * =f(P/P 0 ) and h 3 * =f(P/P 0 ) trajectories achieve the saturation level -compare the conclusions in [31]. The hybrid method provided in the EPRI [2] procedures to estimate the J-integral, the CTOD, and the load line displacement is based on the fixed values of the functions h 1 , h 2 and h 3 [2], which do not depend on the external load.…”

“…The numerical calculations presented in [20][21] and [31] show that the formulae given in the EPRI procedures [19] are not always exact and the results obtained with them differ from those obtained through the finite element analysis. Some of the differences were discussed in [21], where the authors verified the limit load solutions for SEN(T) specimens.…”

“…The new formulae, based on the discussion presented in [19], can be used to determine the J-integral, the CTOD, and the load line displacement; it is possible to omit the decomposition of the elastic and plastic parts of the parameters [31]. The formulae can be written as follows …”