Park, Hyungbum Han, Jang-Woo Na, Wonjin Yu, Jaesang 2024-01-19T10:04:20Z 2024-01-19T10:04:20Z 2023-02-17 2023-02 0263-8223 https://pubs.kist.re.kr/handle/201004/114044 The multiaxial deformation behaviors of amorphous epoxy polymers were characterized using planar biaxial compression tests and finite element (FE) analyses of cruciform specimens. The multiaxial limit of elastic deformation was investigated considering buckling instability of the planar biaxial compression tests. An offset -based yield criterion was proposed to determine the initial yield surface considering the nonlinear elastic deformation characteristics observed in the deformation tests. An FE analysis confirmed using the results of the tests revealed that the proposed method captured the initial multiaxial yielding in the central gauge of the specimen, demonstrating that existing pressure-dependent classical yield functions, such as the paraboloidal and conical yield functions, cannot appropriately describe the initial yield surface of the epoxy polymer. The yield function previously customized from molecular dynamics (MD) data exhibited a relatively good agreement with the initial yield surface. The determined shape of the initial yield surface and its agreement with the MD data-driven yield function were not consistently maintained during subsequent yielding. The results indicate that a new customized yield function properly describing the broader initial yield surface than those of the classical yield functions and its shape transition to plastic behavior is necessary to accurately reflect the entire multiaxial deformation behavior. English Elsevier BV Characterizing the biaxial compressive deformation behavior of epoxy polymer through cruciform experiment and finite element analysis Article 10.1016/j.compstruct.2022.116488 1 Composite Structures, v.305 Composite Structures 305 N scie scopus 000918762700003 2-s2.0-85142759656 Mechanics Materials Science, Composites Mechanics Materials Science Article MECHANICAL RESPONSE STRESS COMPOSITES SURFACES FRACTURE FAILURE SHAPE Epoxy polymer Yield function Cruciform specimen Finite element modeling Multiaxial deformation