A Thermo-Mechanical Coupling Atom-Continuum Coupled Model and Its Algorithm
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摘要: 对热-力耦合的原子-连续关联模型进行了系统研究,给出了计及热-力耦合行为的金属微-纳米构件内材料的瞬态弹性常数,应力、应变、比热容等物理量的具体计算公式及其算法.利用原子运动中的“结构形变”部分来研究微-纳米尺度下多晶原子团簇的非均匀结构变形.将原子团簇晶格结构的变形与连续体的变形关联起来,在准简谐近似假设下,推导出依赖于微观结构变形和热振动的自由能密度、熵密度、内能密度表达式,从而给出了微-纳米尺度下的瞬态热-力学参数.
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关键词:
- 原子-连续关联(ACC)模型 /
- 准简谐近似假设 /
- 自由能密度 /
- 比热容
Abstract: A thermo-mechanical coupling atom-continuum coupled model and its efficient algorithm were studied systematically, and the formulae for calculation of thermodynamic and mechanical parameters of metallic materials in micro/nano-scale were obtained. The heterogeneous structure and deformation of polycrystalline clusters in micro- and nano-scale were studied by means of the‘structural deformation’part of the atomic motion. Then the lattice structural transformation of atomic clusters was related with the continuum deformation, and the expressions of free energy density, entropy density and internal energy density, which were dependent on the micro-structural deformation and thermal vibration, were derived under the quasi-harmonic approximation assumptions, with some transient thermodynamic and mechanical parameters given. The numerical simulation of a tensioning test on a Cu nanowire proves correctness of the proposed model and validity of the algorithm. -
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