http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
임세영(Seyoung Im),최강혁(Kanghyouk Choi) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
In this paper, a finite element analysis of arc-welding processes is presented for large structures. We use an implicit numerical implementation for Leblond’s transformation plasticity constitutive equations, which are widely used in steel-structure welding. Several numerical examples, particularly including a large structure undergoing significant elastic-plastic deformations before welding, are presented to demonstrate the effectiveness of the three-dimensional analysis of welding processes.
B-bar aided edge-based smoothed finite elements of hexahedron type for elasto-plasticity
Son, Youngtak,Im, Seyoung 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.2
<P>The purpose of this study is to perform elastoplastic analysis using an edge-based smoothed finite element of hexahedron type. The edge-based smoothed finite element method has the best performance among the smoothed finite element methods, but has the problem of the volumetric locking phenomenon. Since plastic deformation is an isochoric process, it is accompanied by volumetric locking. In this study, the B-bar approach was introduced in the ESFEM to solve the volumetric locking phenomenon, and to enable elastoplastic analysis. The proposed method was verified to be efficient and accurate by comparison with results from the conventional finite element method.</P>
Kim, Moonhong,Im, Seyoung Elsevier 2017 Computer methods in applied mechanics and engineer Vol.325 No.-
<P><B>Abstract</B></P> <P>An equivalent continuum model for multilayer graphene sheets (MLGSs) and its plate model are developed to analyze the deformation behavior of MLGSs. Hyperelastic material models are introduced for the MLGS continuum model by examining the atomistic structures of MLGSs and obtaining their mechanical properties by means of molecular statics simulations. The MLGS plate model, a structural model for MLGSs, is developed by applying kinematics assumptions to the MLGS continuum model subjected to infinitesimal deformation. Finite element methods (FEM) with the corotational formulation are adopted to analyze the mechanical behavior of MLGSs under small-strain deformation and large rotation conditions. The MLGS plate element passes several basic numerical tests, including patch tests, eigenvalue analyses, and geometrically nonlinear benchmark problems. Finally, the deflections of a plane-strain cantilever and spherical indentations are analyzed by the proposed MLGS plate element and molecular dynamics (MD) simulations. These results show that the MLGS plate element properly represents the deformation behaviors of MLGSs from the atomic scale to the macroscopic continuum scale.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We present a plate finite element able to analyze deformation of MLGSs. </LI> <LI> Interlayer slip and layer deformation are described by kinematics assumptions. </LI> <LI> Corotational formulation is employed for small-strain deformations & large rotations. </LI> <LI> The element is verified as a structural element and a continuum description of MLGSs. </LI> </UL> </P>
An Investigation on Collapse Behavior of Shear Localization in Elasto-Thermo-Viscoplastic Materials
Hyun-Gyu Kim,Seyoung Im 대한기계학회 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.12
The stress collapse in the formation of shear bands in elasto-thermo-viscoplatic materials is systematically studied within the framework of one-dimensional formulation via analytical and numerical methods. The elastic energy released in a domain is found to play an important role in the collapse behavior of shear localization. A non-dimensional parameter named the stability indicator is introduced to characterize the collapse behavior, with approximate forms of the incremental governing equations. The stability indicator offers useful information regarding the degree of severity of an abrupt change of deformations during the stress collapse. Numerical experiments are carried out to verify the stability indicator by varying material properties.