PSI - Issue 68

A.H. Jabbari et al. / Procedia Structural Integrity 68 (2025) 874–879 Jabbari et al. / Structural Integrity Procedia 00 (2025) 000–000

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3. Results and discussion Fig. 4 displays the SIF depending (a) on the applied displacement and (b) on the equivalent contact force for both specimen types, CT and DCB. As the SIF is defined in linear elastic fracture mechanics (LEFM), only the results of specimens with elastic behavior are shown. In general, the SIF increases linearly with increasing displacement and with increasing equivalent contact force, respectively. However, for similar displacements applied, the SIF achieved with CT specimens is greater than the SIF achieved with DCB specimens. Because of the short arms of CT specimens, a higher equivalent contact force is required to induce similar SIF as in DCB specimens. (a) (b)

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Fig. 4. Stress intensity factor (SIF) depending (a) on the applied displacement and (b) on the contact force.

Fig. 5 shows (a) the contact force depending on the applied displacement and (b) the offset of the equivalent contact force from the nominal loading line depending on the applied displacement for elastic behavior and for elastoplastic behavior of both specimen types, CT and DCB. Negative offsets indicate that the equivalent contact force is located closer to the crack tip. In general, the illustrated relationships for specimens with elastoplastic behavior are non-linear, which is due to the plastic deformation of the loaded specimens and which is contrary to the linear relationships for specimens with elastic behavior. Furthermore, a considerable offset of the contact force from the loading line as marked in Fig. 1 can be observed for CT specimens with elastic behavior, whereas the offset is negligible for DCB specimens with elastic behavior. (a) (b)

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Fig. 5. (a) Contact force and (b) offset of the contact force depending on the applied displacement.