PSI - Issue 59

Bernadett Spisák et al. / Procedia Structural Integrity 59 (2024) 3–10 B. Spisa ´ k et al. / Structural Integrity Procedia 00 (2019) 000 – 000

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3.2. Finite element simulation Finite element simulations were performed in MSC. Marc Mentat software to generate the equation describing the stress intensity factor. A 2D plane strain model and a linear elastic material model were applied. For this, 205 GPa was given for the Young’s modulus and 0.3 for the Poisson’s ratio. A symmetry condition in the y direction, a grip in the x direction and a displacement in the y direction under load were given as boundary conditions. These are illustrated in Figure 3.

Fig. 3. Boundary conditions applied on the finite element model.

Fig. 4. Hybrid 0.5T specimen stress intensity factor as a function of loading force.

The crack length range was then determined. For the CT test specimen, the a/W ratio should be between 0.45 and 0.55 in relation to the W dimension, which is the net length of the CT specimen. Taking this into account, the a/W ratio for the specimen shown in Figure 2 was assumed to be between 0.6 and 0.8, where W means the net length of the hybrid specimen. Simulations were carried out for 16 a/W ratios. As a result, the value of the stress intensity factor can be determined for a given a/W ratio. In summary, the stress intensity factor-force curves obtained from the simulations are presented in Figure 4 for the 0.5T specimen, where the curves correspond to the indicated a/W values. 3.3. Determination of the K I formula for hybrid 1T specimen In the next step, a surface was fitted on the curves obtained from the simulation in the form of formula (1) used for the CT specimens. For this, the Matlab software was used, which allows fitting curves and surfaces to given data