scholarly journals Efficient 3D Volume Reconstruction from a Point Cloud Using a Phase-Field Method

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Darae Jeong ◽  
Yibao Li ◽  
Heon Ju Lee ◽  
Sang Min Lee ◽  
Junxiang Yang ◽  
...  

We propose an explicit hybrid numerical method for the efficient 3D volume reconstruction from unorganized point clouds using a phase-field method. The proposed three-dimensional volume reconstruction algorithm is based on the 3D binary image segmentation method. First, we define a narrow band domain embedding the unorganized point cloud and an edge indicating function. Second, we define a good initial phase-field function which speeds up the computation significantly. Third, we use a recently developed explicit hybrid numerical method for solving the three-dimensional image segmentation model to obtain efficient volume reconstruction from point cloud data. In order to demonstrate the practical applicability of the proposed method, we perform various numerical experiments.

2020 ◽  
Vol 55 (5-6) ◽  
pp. 145-158
Author(s):  
Leying Song ◽  
Songhe Meng ◽  
Chenghai Xu ◽  
Guodong Fang ◽  
Qiang Yang ◽  
...  

Virtual tests for a single-fiber–reinforced composite model subjecting to transverse tension are carried out based on a phase-field method considering a varying interface toughness parameter. Without pre-treating the crack initiation location and propagation path, the complete fracture process is realized for the first time in a three-dimensional numerical model, including nucleation cracks on the fiber/matrix interface at the free end, tunneling cracks along the fiber axis, and kinked interface cracks deviating from the interface and penetrating into the matrix. The numerically calculated crack propagation process is in good agreement with the in situ observations in the literature, indicating that the present model provides a good real-time quantitative numerical method for three-dimensional fracture analysis of fiber-reinforced composites. Tunneling cracks tend to cause macroscopic interface debonding and fiber pull-out. The interface tunneling crack initiation and the transition to the steady state inside the model are captured and analyzed in the numerical model. Kinked interface cracks can merge with other matrix cracks, forming a macroscopic transverse crack fracture mode. The kinking behaviors affected by the initial crack size and the interface properties are investigated. This study for the detailed crack propagation is helpful in understanding the toughening mechanism of fiber-reinforced composites under transverse tension.


2014 ◽  
Vol 91 ◽  
pp. 146-152 ◽  
Author(s):  
Changsheng Zhu ◽  
Jinfang Jia ◽  
Li Feng ◽  
Rongzhen Xiao ◽  
Ruihong Dong

2018 ◽  
Vol 8 (12) ◽  
pp. 2488 ◽  
Author(s):  
Sauradeep Bhowmick ◽  
Gui-Rong Liu

The cell based smoothed finite element method (CS-FEM) was integrated with the phase-field technique to model brittle fracture in 3D elastic solids. The CS-FEM was used to model the mechanics behavior and the phase-field method was used for diffuse fracture modeling technique where the damage in a system was quantified by a scalar variable. The integrated CS-FEM phase-field approach provides an efficient technique to model complex crack topologies in three dimensions. The detailed formulation of our combined method is provided. It was implemented in the commercial software ABAQUS using its user-element (UEL) and user-material (UMAT) subroutines. The coupled system of equations were solved in a staggered fashion using the in-built non-linear Newton–Raphson solver in ABAQUS. Eight node hexahedral (H8) elements with eight smoothing domains were coded in CS-FEM. Several representative numerical examples are presented to demonstrate the capability of the method. We also discuss some of its limitations.


Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Jeonghwan Lee ◽  
Kwangheon Park ◽  
Kunok Chang

In this study, the microstructural evolution of an Fe-Cr-Al system was simulated in two-dimensional (2D) and three-dimensional (3D) systems using the phase-field method. We investigated the effect of Al concentration on the microstructural evolution of the systems, with a focus on the nucleation and growth of the Cr-rich α′ phase. In addition, we quantitatively analyzed the mechanism of the effect of Al concentration on the microstructural characteristics of the 2D and 3D systems, such as the number of precipitates, average precipitate area (volume), and α′ phase fraction. In particular, we analyzed the effect of Al concentration and the dimensions of the system cell on the formation of the interconnected structure at high Cr concentrations, such as 35 Crat% and 40 Crat%. To enhance the performance of the simulations, we applied a semi-implicit Fourier spectral method for the ternary system and a parallel graphics processing unit computing technique. The results revealed that the initiation of phase separation in the 2D and 3D simulations was enhanced with an increase in the average Al concentration in the system. In addition, with an increase in the average Al concentration in both systems, the α′ phase fraction increased, while the change in the phase fraction decreased.


Author(s):  
Subramanya Sadasiva ◽  
Ganesh Subbarayan

Diffusion is an important mechanism for failure inducing phenomena in many applications. The common Pb-free solder alloys used in the current generation of electronics packages are complex multiphase multicomponent materials. As the scale of the solder joint decreases, it becomes increasingly important to account for the effect of surface phenomena such as grain boundary evolution, surface diffusion and interfacial reactions in the mechanics of the solder joints. The dynamics of these diffusion driven interfacial phenomena are affected by the state of stress and the electric current in the solid. The primary challenges to modeling the dynamics of evolution are the tracking of the interface while satisfying the boundary conditions for the bulk problem. In previous work, the authors utilized the phase field method in conjunction with a commercial finite element code to study the effect of stress and electrical fields on the diffusion driven evolution of voids in solder interconnects. The utilization of commercial tools for the simulation of the stress, electrical and thermal fields allowed for the use of pre-existing meshes and allowed the study of electromigration failure in assemblies of solder joints. However, the use of commercial tools can be expensive and the options for parallel simulation are limited, restricting the size and complexity of the simulations. In this work, the authors describe DiffCode, a parallel adaptive finite element code for three-Dimensional simulation of electromigration and stress migration driven failure due to void evolution and growth in solder as well as line interconnects using the phase field method. Several illustrative two-dimensional and three-dimensional electromigration driven void evolution simulations are demonstrated using the code.


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