Zhao Zhang^1,*, Xiang Gao¹, Yifei Wang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.3, pp. 1-1, 2024, DOI:10.32604/icces.2024.012115

Abstract Wire arc additive manufacturing (WAAM) reveals its high efficiency for the fabrications in comparison with laser additive manufacturing. To reveal the relationship between arc settings and the microstructural evolutions, phase field model and Monte Carlo model are established for the simulation of the microstructural evolutions and dislocation dynamics model is established for the simulation of the anisotropic properties in WAAM. Numerical results are compared with Experiments to validate the proposed models. The length/width ratio of the formed grains in solidification becomes smaller when the scanning speed is decreased or the input powder is increased. The… More >

Yang Chen¹, Jing Peng¹, Shuo Wang¹, Chao Jiang¹, Jia Li^1,*, Qihong Fang^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.4, pp. 1-2, 2024, DOI:10.32604/icces.2024.012299

Abstract Nuclear energy demands radiation-resistant metal materials. Multi-principal element alloys (MPEAs) show superior radiation resistance over traditional alloys due to lattice distortion, promising for advanced reactors. However, damage evolution and mechanical performance of irradiated MPEAs under loading are unclear, limiting long-term application. We investigated hardening behavior induced by irradiation defects like dislocation loops and voids in MPEAs using crystal plasticity models and experiments. Here, we developed i) a stochastic field theory-based discrete dislocation dynamics simulation. A novel cross-slip mechanism in irradiated crystals was unveiled through co-linear reactions between dislocations and diamond perfect loops [1]; ii) With… More >

Jin Ma, Yang Liu, Hongbing Lu, Ranga Komanduri¹

CMES-Computer Modeling in Engineering & Sciences, Vol.16, No.1, pp. 41-56, 2006, DOI:10.3970/cmes.2006.016.041

Abstract A multiscale simulation technique coupling three scales, namely, the molecular dynamics (MD) at the atomistic scale, the discrete dislocations at the meso scale and the generalized interpolation material point (GIMP) method at the continuum scale is presented. Discrete dislocations are first coupled with GIMP using the principle of superposition (van der Giessen and Needleman (1995)). A detection band seeded in the MD region is used to pass the dislocations to and from the MD simulations (Shilkrot, Miller and Curtin (2004)). A common domain decomposition scheme for each of the three scales was implemented for parallel More >

K. Yashiro¹, Y. Nakashima¹, Y. Tomita¹

CMES-Computer Modeling in Engineering & Sciences, Vol.11, No.2, pp. 73-80, 2006, DOI:10.3970/cmes.2006.011.073

Abstract A simple back force model is proposed for a dislocation cutting into γ' precipitate, taking the work formaking and recovering an anti-phase boundary (APB) into account. The first dislocation, or a leading partial of a superdislocation, is acted upon by a back force whose magnitude is equal to the APB energy. The second dislocation, or a trailing partial of a superdislocation, is attracted by the APB with a force of the same magnitude. The model is encoded in the 3D discrete dislocation dynamics (DDD) code and applied to the cutting behavior of dislocations at a… More >

Xiangli Liu¹, S. I. Golubov¹, C. H. Woo^1,2, Hanchen Huang³

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.6, pp. 527-540, 2004, DOI:10.3970/cmes.2004.005.527

Abstract A Green’s function technique is developed for the relaxation of simulation cell boundaries in the modelling of dislocation interactions using molecular dynamics. This method allows the replacement of fixed or periodical boundary conditions with flexible boundary conditions, thus minimizing the artificial effects due to images forces introduced by the fixed boundary condition, or the periodic repetition of simulation cells. The effectiveness of the Green’s function in the removal of the fixed boundary image forces is first checked in the atomistic simulation involving the glide of the a/2<110> dislocation in bcc tungsten. This method is then applied More >

R. Martinez¹, N. M. Ghoniem²

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.2, pp. 229-244, 2002, DOI:10.3970/cmes.2002.003.229

Abstract We focus here on the direct coupling of Dislocation Dynamics (DD) computer simulations with the Finite Element Method (FEM) to simulate plastic deformation of micro-scale structures, and investigate the influence of crystal surfaces on dislocation motion. A series of three-dimensional (3-d) DD simulations of BCC single crystals with a single shear loop in the (101)-[111] slip system are first presented. The purpose of these simulations is to explore the relationship between loop force distributions and the proximity of the loop to the crystal boundary. Traction boundary conditions on a single crystal model are satisfied through… More >