基于有限差分法和光滑粒子法的镁合金充型模拟

针对Benchmark件,采用有网格方法(FDM)和无网格方法(SPH)进行充型过程数值模拟,并将模拟结果与WinCast计算结果进行了比对,从而验证了两种方法的有效性和正确性。由于SPH方法可通过追踪粒子的运动得到整个物理系统的特性,无需采用专门方法确定自由表面,在数学模型上具有一定优势。     

基于SPH方法的低压铸造充型过程数值模拟

借助光滑粒子流体动力学(SPH)方法,对所建立的低压铸造充型模型进行了数值模拟,并将模拟结果与Win-cast软件的模拟结果进行对比。结果表明,SPH方法与Win-cast软件模拟结果基本一致,能够较准确地模拟低压铸造充型过程。     

First-principles study on effect of pressure and temperature on structural, elastic, thermodynamic, and electronic properties of Ni3Al alloy

The influence of temperature and pressure on the electronic, elastic, structural, and thermodynamic properties of Ni3Al alloy was investigated by performing a first-principles study. The calculated elastic constants, equilibrium lattice constants, and elastic modulus agree well with the recorded theoretical and experimental data. The calculated elastic constants indicate that C11 is more sensitive than C12 and C44 to pressure. The Young’s modulus, bulk modulus, and shear modulus increase with an increase in pressure. The ratio of bulk to shear modulus (B/G) and anisotropy factor A were also analyzed. The Debye temperature was obtained by calculating the elastic constants, and it changed with the change in the pressure. The thermal expansion coefficient, normalized volume, heat capacity, bulk modulus, and Debye temperature Θ were determined and analyzed by using the quasi-harmonic Debye model at pressures of 0–60 GPa and temperatures of 0–1600 K. Finally, the density of states and Mulliken population were investigated and the effect of pressure on these was analyzed.     

基于近似因子分解法和SPH法的医用挤压铸件充型模拟

采用近似因子分解法、光滑粒子流体动力学法进行挤压铸造充型过程数值模拟研究。模拟结果显示,近似因子分解法、光滑粒子流体动力学法(SPH)计算结果与Win-cast铸造模拟软件计算结果基本一致,从而验证了两种方法的有效性和准确性。由于SPH的粒子携带材料性质,能够在空间中运动,较传统的有限差分法而言,不存在自由表面和运动物质交界面等的位置难以精确确定的问题,在数学模型的建立方面具有一定优势。     

基于SPH法的AZ31镁合金ECAP过程数值模拟

引入一种新的无网格法——光滑粒子流体动力学法(Smooth Particle Hydrodynamics,SPH),将问题域离散为一系列粒子,避免了由于网格的划分导致计算精度下降。通过建立数学模型并编写SPH方法程序,对AZ31镁合金ECAP过程在高挤压速度下的裂纹萌生和扩展进行数值模拟,并将模拟结果与有限元模拟结果及试验结果进行对比,验证了所建SPH程序的准确性及可行性。