Computational experiments are carried out in three-dimensional, multi-fibre specimens with the objective of determining the influence of fibre volume fraction (phi) and aspect ratio (a(r)) on the effective tensile mod...
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Computational experiments are carried out in three-dimensional, multi-fibre specimens with the objective of determining the influence of fibre volume fraction (phi) and aspect ratio (a(r)) on the effective tensile modulus of aligned, discontinuous fibre-reinforced composites. The Boundary Element Method (BEM), implemented on a 1840-node Intel Paragon parallel supercomputer using a torus-wrap mapping, enables the prediction of the tensile behaviour of composite specimens consisting of up to 200 discrete aligned short fibres, randomly dispersed in an elastic matrix. Statistical averages of the computed effective longitudinal moduli are compared with the predictions of the Halpin-Tsai equation and are found to be in good agreement for low values of a(r) and phi. However, as a(r) and/or phi increase, the predictions of the Halpin-Tsai equation fall below the computed moduli. Consideration of the finite packing efficiency of the fibres as proposed by Lewis and Nielsen results in a generalized form of the Halpin-Tsai equation whose predictions are in very good agreement with the BEM calculations for the entire range of phi and a(r) examined. The scatter in the computed moduli decreases with increasing number of fibres, reflecting the 'homogenization' of the specimen brought about by consideration of larger numbers of smaller fibres. This scatter grows with increasing phi and a(r), reflecting an increase in the magnitude and complexity of inter-fibre interactions. (C) 1997 by John Wiley & Sons, Ltd.
Computational experiments are carried out in three-dimensional, multi-fibre specimens with the objective of determining the influence of fibre volume fraction (ϕ) and aspect ratio ( a r ) on the effective tensile modu...
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作者:
LEISERSON, CELab. for Comput. Sci.
MIT Cambridge MA USA Abstract Authors References Cited By Keywords Metrics Similar Download Citation Email Print Request Permissions
The author presents a new class of universal routing networks, called fat-trees, which might be used to interconnect the processors of a general-purpose parallel supercomputer. A fat-tree routing network is parameteri...
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The author presents a new class of universal routing networks, called fat-trees, which might be used to interconnect the processors of a general-purpose parallel supercomputer. A fat-tree routing network is parameterized not only in the number of processors, but also in the amount of simultaneous communication it can support. Since communication can be scaled independently from the number of processors, substantial hardware can be saved for such applications as finite-element analysis without resorting to a special-purpose architecture. It is proved that a fat-tree of a given size is nearly the best routing network of that size. This universality theorem is established using a three-dimensional VLSI model that incorporates wiring as a direct cost. In this model, hardware size is measured as physical volume. It is proved that for any given amount of communications hardware, a fat-tree built from that amount of hardware can stimulate every other network built from the same amount of hardware, using only slightly more time (a polylogarithmic factor greater).
A large scale simulation for polymer chains in good solvent is performed. The implementation technique for efficient parallel execution, optimization, and load-balancing are discussed on this practical application. Fi...
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A large scale simulation for polymer chains in good solvent is performed. The implementation technique for efficient parallel execution, optimization, and load-balancing are discussed on this practical application. Finally a simple performance model is proposed.
Discrete solution to nonlinear systems problems that leads to a series of linear problems associated with non-invariant large-scale sparse symmetric positive matrices is herein considered. Each linear problem is solve...
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Discrete solution to nonlinear systems problems that leads to a series of linear problems associated with non-invariant large-scale sparse symmetric positive matrices is herein considered. Each linear problem is solved iteratively by a conjugate gradient method. We introduce in this paper new solvers (IRKS, GIRKS and D-GIRKS) that rely on an iterative reuse of Krylov subspaces associated with previously solved linear problems. Numerical assessments are provided on large-scale engineering applications. Considerations related to parallel supercomputing are also addressed.
The numerical simulation is performed for the damage induced acoustic emission and the wave propagation event of composite plates by the finite element transient analysis. The acoustic emission and the following wave ...
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ISBN:
(纸本)0819457450
The numerical simulation is performed for the damage induced acoustic emission and the wave propagation event of composite plates by the finite element transient analysis. The acoustic emission and the following wave motions from a predictable damage under a static loading is simulated to investigate the applicability of the explicit finite element method and the equivalent volume force model as a simulation tool of wave propagation and a modeling technique of an acoustic emission. For such a simple case of the damage event under static loading, various parameters affecting the wave motion are investigated for reliable simulations of the impact damage event. The numerical experiment is also conducted for simulating the full procedures from the impact phenomenon to the damage induced acoustic emission wave. The numerically reproduced wave signal is transformed by wavelet transform to analyze the frequency and the resolution characteristics between the acoustic emission signals of various damage mechanisms. The high velocity and the small wave length of the acoustic emission require a refined analysis with dense distribution of the finite element and a small time step. In order to fulfill the requirement for capturing the exact wave propagation and to cover the 3-D simulation, we utilize the parallel FE transient analysis code and the high performance computing(HPC) technology.
Tato bakalářská práce srovnává několik nástrojů pro realizaci škálovatelné platformy strojového učení a popisuje jejich výhody a nevýhody. Dále prá...
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Tato bakalářská práce srovnává několik nástrojů pro realizaci škálovatelné platformy strojového učení a popisuje jejich výhody a nevýhody. Dále práce prakticky realizuje funkčnost škálovatelné platformy založené na nástroji Apache Hadoop a zabývá se měřením výkonu samoučícího algoritmu K-Means pomocí knihoven strojového učení Apache Mahout na celkem pěti výpočetních uzlech.
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