유한요소해석 기반 극박 순 타이타늄 판재의 평면 변형 노치 인장 시편 설계 및 검증

초록

In this study, notch tension (NT) specimens were designed and experimentally validated to reproduce the plane strain state for a 0.1 mm thick commercially pure titanium (CP-Ti) sheet. Finite element (FE) analyses incorporating an evolutionary anisotropic yield function (Yld2000-2d) were performed for the specimen design. In particular, attempts were made to design a specimen geometry that prevents fracture from the edge of notch caused by the excessively thin sheet thickness, and instead to promotes fracture at the center of the gauge section. Finally, specimens with notch radii of 2.5 and 4 mm were identified as optimal geometries. Tensile tests combined with digital image correlation (DIC) were conducted on the selected specimens. The two specimens exhibited fracture from the gauge center, consistent with the FE predictions. The minor-to-major strain ratio (ρ) measured by DIC was approximately −1/3, confirming that the designed specimens provide a valid geometry for characterizing fracture behavior at the plane strain condition for the 0.1 mm thick CP-Ti sheet.

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