scholarly journals A Finite Element Mesh Regrouping Strategy-Based Hybrid Light Transport Model for Enhancing the Efficiency and Accuracy of XLCT

2022 ◽  
Vol 11 ◽  
Author(s):  
Yanqiu Liu ◽  
Xiangong Hu ◽  
Mengxiang Chu ◽  
Hongbo Guo ◽  
Jingjing Yu ◽  
...  
Keyword(s):  
Finite Element ◽  
Optical Transmission ◽  
Transport Model ◽  
Harmonic Approximation ◽  
Finite Element Mesh ◽  
Light Transport ◽  
Transmission Model ◽  
System Matrix ◽  
Element Mesh ◽  
Simulation Results

X-ray luminescence computed tomography (XLCT) is an emerging hybrid imaging modality in optical molecular imaging, which has attracted more attention and has been widely studied. In XLCT, the accuracy and operational efficiency of an optical transmission model play a decisive role in the rapid and accurate reconstruction of light sources. For simulation of optical transmission characteristics in XLCT, considering the limitations of the diffusion equation (DE) and the time and memory costs of simplified spherical harmonic approximation equation (SPN), a hybrid light transport model needs to be built. DE and SPN models are first-order and higher-order approximations of RTE, respectively. Due to the discontinuity of the regions using the DE and SPN models and the inconsistencies of the system matrix dimensions constructed by the two models in the solving process, the system matrix construction of a hybrid light transmission model is a problem to be solved. We provided a new finite element mesh regrouping strategy-based hybrid light transport model for XLCT. Firstly, based on the finite element mesh regrouping strategy, two separate meshes can be obtained. Thus, for DE and SPN models, the system matrixes and source weight matrixes can be calculated separately in two respective mesh systems. Meanwhile, some parallel computation strategy can be combined with finite element mesh regrouping strategy to further save the system matrix calculation time. Then, the two system matrixes with different dimensions were coupled though repeated nodes were processed according to the hybrid boundary conditions, the two meshes were combined into a regrouping mesh, and the hybrid optical transmission model was established. In addition, the proposed method can reduce the computational memory consumption than the previously proposed hybrid light transport model achieving good balance between computational accuracy and efficiency. The forward numerical simulation results showed that the proposed method had better transmission accuracy and achieved a balance between efficiency and accuracy. The reverse simulation results showed that the proposed method had superior location accuracy, morphological recovery capability, and image contrast capability in source reconstruction. In-vivo experiments verified the practicability and effectiveness of the proposed method.

scholarly journals Influence of finite element mesh size on the carrying capacity analysis of single-row ball slewing bearing

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110090
Author(s):  
Peiyu He ◽  
Qinrong Qian ◽  
Yun Wang ◽  
Hong Liu ◽  
Erkuo Guo ◽  
...  
Keyword(s):  
Finite Element ◽  
Carrying Capacity ◽  
Mesh Size ◽  
Finite Element Mesh ◽  
Fe Model ◽  
Element Mesh ◽  
Heavy Load ◽  
Slewing Bearing ◽  
Maximum Contact ◽  
Slewing Bearings

Slewing bearings are widely used in industry to provide rotary support and carry heavy load. The load-carrying capacity is one of the most important features of a slewing bearing, and needs to be calculated cautiously. This paper investigates the effect of mesh size on the finite element (FE) analysis of the carrying capacity of slewing bearings. A local finite element contact model of the slewing bearing is firstly established, and verified using Hertz contact theory. The optimal mesh size of finite element model under specified loads is determined by analyzing the maximum contact stress and the contact area. The overall FE model of the slewing bearing is established and strain tests were performed to verify the FE results. The effect of mesh size on the carrying capacity of the slewing bearing is investigated by analyzing the maximum contact load, deformation, and load distribution. This study of finite element mesh size verification provides an important guidance for the accuracy and efficiency of carrying capacity of slewing bearings.

Optimization of a finite element mesh for plates subjected to in-plane patch loading

2019 ◽  
Vol 33 (3) ◽  
pp. 1185-1193 ◽  
Author(s):  
Ghania Ikhenazen ◽  
Messaoud Saidani ◽  
Madina Kilardj
Keyword(s):  
Finite Element ◽  
Finite Element Mesh ◽  
Element Mesh ◽  
Patch Loading

A hybrid method for terminating the finite-element mesh (electrostatic case)

1995 ◽  
Vol 8 (6) ◽  
pp. 282-287 ◽  
Author(s):  
Tanmoy Roy ◽  
Tapan K. Sarkar ◽  
Antonije R. Djordjevic ◽  
Magdalena Salazar-Palma
Keyword(s):  
Finite Element ◽  
Hybrid Method ◽  
Finite Element Mesh ◽  
Element Mesh

Finite Element Mesh Generator Applying Constraints’ Propagation and Isoparametric Mapping

1991 ◽  
Author(s):  
J. Rodriguez ◽  
M. Him
Keyword(s):  
Finite Element ◽  
Mesh Generation ◽  
Element Model ◽  
Finite Element Mesh ◽  
Fe Model ◽  
Element Analysis ◽  
Element Mesh ◽  
Mesh Generator ◽  
Generation Algorithm ◽  
Essential Input

Abstract This paper presents a finite element mesh generation algorithm (PREPAT) designed to automatically discretize two-dimensional domains. The mesh generation algorithm is a mapping scheme which creates a uniform isoparametric FE model based on a pre-partitioned domain of the component. The proposed algorithm provides a faster and more accurate tool in the pre-processing phase of a Finite Element Analysis (FEA). A primary goal of the developed mesh generator is to create a finite element model requiring only essential input from the analyst. As a result, the generator code utilizes only a sketch, based on geometric primitives, and information relating to loading/boundary conditions. These conditions represents the constraints that are propagated throughout the model and the available finite elements are uniformly mapped in the resulting sub-domains. Relative advantages and limitations of the mesh generator are discussed. Examples are presented to illustrate the accuracy, efficiency and applicability of PREPAT.

A Constrained Optimization Approach to Finite Element Mesh Smoothing

1991 ◽  
Author(s):  
V. N. Parthasarathy ◽  
Srinivas Kodiyalam
Keyword(s):  
Finite Element ◽  
Constrained Optimization ◽  
Finite Element Mesh ◽  
Optimization Approach ◽  
Element Mesh ◽  
Initial Mesh ◽  
Nodal Coordinates ◽  
Automatic Mesh ◽  
Mesh Generators

Abstract The quality of a finite element solution has been shown to be affected by the quality of the underlying mesh. A poor mesh may lead to unstable and lor inaccurate finite element approximations. Mesh quality is often characterized by the “smoothness” or “shape” of the elements (triangles in 2-D or tetrahedra in 3-D). Most automatic mesh generators produce an initial mesh where the aspect ratio of the elements are unacceptably high. In this paper, a new approach to produce acceptable quality meshes from an initial mesh is presented. Given an initial mesh (nodal coordinates and element connectivity), a “smooth” final mesh is obtained by solving a constrained optimization problem. The variables for the iterative optimization procedure are the nodal coordinates (excluding, the boundary nodes) of the finite element mesh, and appropriate bounds are imposed on these to prevent an unacceptable finite element mesh. Examples are given of the application of the above method for 2/3-D triangular meshes generated using a QUADTREE | OCTREE automatic mesh generators. Results indicate that the new method not only yields better quality elements when compared with the traditional Laplacian smoothing, but also guarantees a valid mesh unlike the Laplacian method.

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