Jike Han 교수

Abstract This study presents a gradient damage model for ductile fracture, in which the damage hardening modulus is degraded by the accumulation of plastic deformation and the volume expansion caused by negative hydrostatic pressure. The proposed model fulfills the thermodynamic requirements, and the governing equations are derived from energy minimization principles. Two parameter studies are carried out to confirm the basic performance of the proposed model, in which some typical ductile fract

Summary This study presents an enhancement of the diffusive‐discrete crack transition scheme (10.1002/nme.7169) to describe dynamic fracture at finite strain. In the enhanced scheme, the crack initiation, propagation, and bifurcation processes are determined from an energy minimization problem based on crack phase‐field theory, and the predicted diffusive crack is replaced by the discrete representation using the finite cover method. In the meantime, numerical damping is introduced to maintain c

This study presents a unified formulation of topology optimization with a finite strain nonlocal damage model using the continuous adjoint method. For the primal problem to describe the material response including deterioration, we consider the standard Neo–Hookean constitutive model and incorporate crack phase-field theory for brittle fracture within the finite strain framework. For the optimization problem, the objective function is set to accommodate multiple objectives by weighting each sub-

Purpose This study aims to develop a new analysis approach devised by incorporating a gradient-enhanced microplane damage model (GeMpDM) into isogeometric analysis (IGA), which shows computational stability and capability in accurately predicting crack propagations in structures with complex geometries. Design/methodology/approach For the non-local microplane damage modeling, the maximum modified von-Mises equivalent strain among all microplanes is regularized as a representative quantity. This

Abstract This study presents a novel transition scheme that can trace an actual crack path as closely as possible and stably update its explicit crack tip even in a large deformation regime. The crack initiation and propagation processes are determined from an energy minimization problem with respect to the displacement field and crack phase‐field, and the predicted path represented by a diffuse crack topology is replaced by a discrete path by applying the finite cover method. By developing a te

Summary This study presents a diffusive‐discrete crack transition scheme for stably conducting ductile fracture simulations within a finite strain framework. In the developed scheme, the crack initiation and propagation processes are determined according to an energy minimization problem based on crack phase‐field theory, and the predicted diffusive path is transformed to a discrete representation using the finite cover method during the staggered iterative scheme. In particular, for stably cond

The cutting forces during cutting can visually reflect various conditions of the cutting process, such as tool wear and workpiece machining. Based on the decagonal ring, a fully aligned integrated cutting force sensor is designed, and a calibration collet is designed for the calibration of the 3D force, and the sensor is encapsulated. The sensor and the calibration collet are calibrated by finite element software, and the first six orders of inherent frequencies and modal vibration patterns are