A distributed memory parallel implementation of the multigrid method for solving three-dimensional implicit solid mechanics problems

2004 ◽  
Vol 61 (8) ◽  
pp. 1173-1208 ◽  
Author(s):  
A. Namazifard ◽  
I. D. Parsons
Keyword(s):  
Distributed Memory ◽  
Multigrid Method ◽  
Solid Mechanics ◽  
Parallel Implementation ◽  
Three Dimensional ◽  
Implicit Solid

IMPLEMENTATION OF THE Z-BUFFER ALGORITHM ON A RECONFIGURABLE NETWORK OF PROCESSORS

1992 ◽  
Vol 06 (02n03) ◽  
pp. 417-436
Author(s):  
JIAN-JIN LI ◽  
SERGE MIGUET ◽  
YVES ROBERT
Keyword(s):  
Distributed Memory ◽  
Interconnection Network ◽  
Parallel Implementation ◽  
Three Dimensional ◽  
The Other ◽  
Global Performance ◽  
Scene Description ◽  
Sequential Implementation ◽  
Better Than ◽  
Special Algorithm

This paper describes the parallel implementation of the Z-Buffer algorithm on a distributed memory machine. The Z-Buffer is one of the most popular techniques used to generate a representation of a scene consisting of objects in a three-dimensional world. We propose and compare two different parallel implementations on a reconfigurable network of Transputers. In the first approach, the description of the scene is distributed among the processors configured as a tree. The picture is processed in a pipelined fashion, in order to output parts of the image during the computation of the remainder. We show the influence of the degree and the height of the tree on the global performance of the algorithm. In a second approach, both the picture and the scene description are distributed to the processors. We have therefore to redistribute dynamically the tiles among the processors at the beginning of the computation. To perform this redistribution, a special algorithm is designed for the case where the processors are configured as a unidirectional or bidirectional ring. Then we implement a greedy algorithm that enables us to perform the redistribution on an arbitrary interconnection network. We show that the two approaches are complementary: for small pictures or large scenes, a tree-based algorithm performs better than a redistribution-based algorithm, but for large pictures or smaller scenes, it is the other way round. We obtain substantial speedups over the sequential implementation, with up to 32 processors.

Computation of Flow Through a Three-Dimensional Periodic Array of Porous Structures by a Parallel Immersed-Boundary Method

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Zhenglun Alan Wei ◽  
Zhongquan Charlie Zheng ◽  
Xiaofan Yang
Keyword(s):  
Porous Media ◽  
Parallel Implementation ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Periodic Array ◽  
Immersed Boundary ◽  
Navier Stokes Equation ◽  
Flow Through ◽  
Ib Method

A parallel implementation of an immersed-boundary (IB) method is presented for low Reynolds number flow simulations in a representative elementary volume (REV) of porous media that are composed of a periodic array of regularly arranged structures. The material of the structure in the REV can be solid (impermeable) or microporous (permeable). Flows both outside and inside the microporous media are computed simultaneously by using an IB method to solve a combination of the Navier–Stokes equation (outside the microporous medium) and the Zwikker–Kosten equation (inside the microporous medium). The numerical simulation is firstly validated using flow through the REVs of impermeable structures, including square rods, circular rods, cubes, and spheres. The resultant pressure gradient over the REVs is compared with analytical solutions of the Ergun equation or Darcy–Forchheimer law. The good agreements demonstrate the validity of the numerical method to simulate the macroscopic flow behavior in porous media. In addition, with the assistance of a scientific parallel computational library, PETSc, good parallel performances are achieved. Finally, the IB method is extended to simulate species transport by coupling with the REV flow simulation. The species sorption behaviors in an REV with impermeable/solid and permeable/microporous materials are then studied.

scholarly journals Fracture of Protective Structures from Heavy Reinforcing Cement During Interaction with High-velocity Impactor

2021 ◽  
Vol 14 (6) ◽  
pp. 779-786
Author(s):  
Pavel A. Radchenko ◽  
◽  
Stanislav P. Batuev ◽  
Andrey V. Radchenko
Keyword(s):  
Reinforced Concrete ◽  
High Velocity ◽  
Solid Mechanics ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Free Surfaces ◽  
Local Fracture Criterion ◽  
Protective Structures ◽  
Concrete Barrier ◽  
Limiting Value

In this work, the fracture of a reinforced concrete barrier made of heavy reinforced ce- ment is numerically simulated during normal interaction with a high-velocity titanium projectile. The projectile has the initial velocity 750 m/s. The problem of impact interaction is numerically solved by the finite element method in a three-dimensional formulation within a phenomenological framework of solid mechanics. Numerical modeling is carried out using an original EFES 2.0 software, which al- lows a straightforward parallelization of the numerical algorithm. Fracture of concrete is described by the Johnson-Holmquist model that includes the strain rate dependence of the compressive and tensile strengths of concrete. The computational algorithm takes into account the formation of discontinuities in the material and the fragmentation of bodies with the formation of new contact and free surfaces. The behavior of the projectile material is described by an elastoplastic medium. The limiting value of the plastic strain intensity is taken as a local fracture criterion for the projectile material. A detailed numerical analysis was performed to study the stress and strain dynamics of the reinforced concrete target and the effect of shock-wave processes on its fracture. The influence of reinforcement on the resistance of a heavy cement target to the penetration of a projectile has been investigated

Three-dimensional morphological analysis method for geologic bodies and its parallel implementation

2016 ◽  
Vol 96 ◽  
pp. 11-22 ◽  
Author(s):  
Xiancheng Mao ◽  
Bin Zhang ◽  
Hao Deng ◽  
Yanhong Zou ◽  
Jin Chen
Keyword(s):  
Morphological Analysis ◽  
Parallel Implementation ◽  
Three Dimensional ◽  
Analysis Method

The Effect of Cracks Interaction on the Critical Strain in Orthotropic Heterogeneous Material Under Compressive Static Loading

2006 ◽  
Author(s):  
B. Winiarski ◽  
I. A. Guz
Keyword(s):  
Critical Strain ◽  
Solid Mechanics ◽  
Crack Opening ◽  
Three Dimensional ◽  
Heterogeneous Material ◽  
Stability Loss ◽  
Orthotropic Materials ◽  
Mutual Position ◽  
Finite Elements Analysis ◽  
Size Dispersion

Laminar composites due to their internal structure and manufacturing methods contain a number of inter- and intra- component defects which size, dispersion and mutual interaction alter significantly the critical compression strain level. The current paper is one of the first attempts to study the crack interaction in orthotropic materials compressed in a static manner along interlaminar defects. For laminated composites compressed along layers and, therefore, along the mentioned interfacial defects, the classical Griffith - Irvin criterion of fracture or its generalization are inapplicable and all stresses intensity factors and crack opening displacements are equal to zero. This fact emphasises the importance and the necessity of the most careful investigation of fracture due to specific mechanisms inherent to heterogeneous materials. The statement of the problem is based on the most accurate approach, the model of piecewise-homogenous medium. The moment of stability loss in the microstructure of material is treated as the onset of the fracture process. The behaviour of each constituent is described by the three-dimensional equations of solid mechanics, provided certain boundary conditions are satisfied at the interfaces. The complex non-classical fracture mechanics problem is solved by finite elements analysis, using linear buckling model. Numerical analysis is aided by the advanced FE analysis software - Abaqus 6.5. The results were obtained for particular cases of real composites for the typical dispositions of cracks. It was found that both cracks length and mutual position of cracks influence the critical strain of the composite.

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