| 1 | Mold-Filling Ability of Aluminum Alloy Melt during the Two-Step Foaming Process显示文摘For the two-step foaming method,one of the most cost-effective ways to fabricate three-dimensional shaped aluminum alloy foams with dense outer surface skin,it is crucial to describe and predict the moldfilling behavior of the shaped aluminum alloy foams with a favorable pore-distribution accurately.In this paper,a mold-filling model for semi-solid aluminum alloy foams was initially established and subsequently employed to predict the filling height,which represents the mold-filling ability of semi-solid aluminum alloy foams in a specially designed tube-like mold.Our results indicate that the proposed model can be applied to characterize the mold-filling property of aluminum alloy melts in a quantitative manner.Theoretically,our findings actually provide a guideline for mass-production of the shaped aluminum alloy foams by using the two-step foaming process. | H.Wang Y.M.Zhang B.C.Zhou D.H.Yang Y.Wu X.J.Liu Z.P.Lu | 2016 | Journal of Materials Science & Technology2016，32，6： | 2 |
| 2 | A Strong Stability-Preserving Predictor-Corrector Method for the Simulation of Elastic Wave Propagation in Anisotropic Media显示文摘In this paper,we propose a strong stability-preserving predictor-corrector(SSPC)method based on an implicit Runge-Kutta method to solve the acoustic-and elastic-wave equations.We first transform the wave equations into a system of ordinary differential equations(ODEs)and apply the local extrapolation method to discretize the spatial high-order derivatives,resulting in a system of semi-discrete ODEs.Then we use the SSPC method based on an implicit Runge-Kutta method to solve the semi-discrete ODEs and introduce a weighting parameter into the SSPC method.On top of such a structure,we develop a robust numerical algorithm to effectively suppress the numerical dispersion,which is usually caused by the discretization of wave equations when coarse grids are used or geological models have large velocity contrasts between adjacent layers.Meanwhile,we investigate the performance of the SSPC method including numerical errors and convergence rate,numerical dispersion,and stability criteria with different choices of the weighting parameter to solve 1-D and 2-D acoustic-and elastic-wave equations.When the SSPC is applied to seismic simulations,the computational efficiency is also investigated by comparing the SSPC,the fourth-order Lax-Wendroff correction(LWC)method,and the staggered-grid(SG)finite differencemethod.Comparisons of synthetic waveforms computed by the SSPC and analytic solutions for acoustic and elastic models are given to illustrate the accuracy and the validity of the SSPCmethod.Furthermore,several numerical experiments are conducted for the geological models including a 2-D homogeneous transversely isotropic(TI)medium,a two-layer elastic model,and the 2-D SEG/EAGE salt model.The results show that the SSPC can be used as a practical tool for large-scale seismic simulation because of its effectiveness in suppressing numerical dispersion even in the situations such as coarse grids,strong interfaces,or high frequencies. | D.H.Yang N.Wang E.Liu | 2012 | Communications in Computational Physics2012，12，9： | 0 |
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