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中国物理学会期刊

结合高压热弹性模拟数据的Hugoniot弹性极限实验解读

Interpretation of Hugoniot elastic limit experiments based on high-pressure thermoelastic simulations

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  • 针对冲击加载实验中波前弥散及非稳态效应制约Hugoniot 弹性极限(HEL)精确解读的问题, 本文提出了一种结合理论模拟与实验数据的自洽解读方法. 该方法基于宏观粒子动量守恒定律与微观材料本征纵波声速响应的物理关联, 构建了以纵波声速和轴向应力为核心变量的自洽方程. 在求解策略上, 以实验测得的弹性前驱波粒子速度为约束变量, 并利用平均场势(MFP)耦合准静态近似(QSA)生成的宽压域热弹性数据集, 构建了连续的纵波声速-压力响应关系. 本文以金刚石为研究对象验证该方法的有效性, 首先构建了室温下0—1000 GPa压区的金刚石热弹性数据集, 其与15 GPa压力范围内静加载实验数据的相对偏差不超过0.4%. 在此基础上, 整合了峰值应力高达1 TPa的金刚石冲击实验数据, 应用上述方法重新解读了HEL. 结果表明, 重新解读的HEL与标准气炮加载实验值的相对偏差在2%以内, 并定量表征了其各向异性. 此外, 针对激光加载实验中因非稳态衰减导致的系统性偏差, 本方法将其HEL值向上修正了8%—13%. 本文数据集可在https://doi.org/10.57760/sciencedb.j00213.00274中访问获取.

    The Hugoniot elastic limit (HEL) serves as the critical stress threshold demarcating the transition from purely elastic to elastoplastic response under dynamic loading. Accurate determination of the HEL is essential for understanding dynamic mechanical behavior. Traditionally, the HEL is derived from the “double-wave” structure of free-surface velocity profiles. However, wavefront dispersion of the elastic precursor and non-steady-state effects in short-pulse laser-driven experiments introduce systematic deviations in longitudinal sound velocity measurements, thereby limiting precise HEL determination. To address these challenges, a self-consistent interpretation method integrating macroscopic conservation laws with microscopic thermoelastic simulations is established.
    Based on momentum conservation, this work establishes a self-consistent equation that relates axial stress to longitudinal sound velocity and particle velocity. This equation corresponds to the process in which high-stress perturbations catch up with low-stress wavefronts. Using the experimentally measured elastic-precursor particle velocity as the constraint, the HEL and the corresponding longitudinal sound velocity can be determined self-consistently by iteratively solving this equation, without relying on ambiguous wavefront arrival-time measurements. To support this procedure, a continuous sound velocity-pressure constitutive relationship is derived from a high-pressure thermoelastic dataset spanning 0–1000 GPa, constructed using density functional theory combined with the mean-field potential (MFP) method and the quasi-static approximation (QSA).
    The validity of this approach is verified using diamond as a benchmark material. The predicted elastic moduli agree with static compression data within 0.4% relative deviation up to 15 GPa. For gas-gun experiments with peak stresses reaching 1 TPa, the reinterpreted HEL values show less than 2% relative deviation from standard experimental benchmarks. These results quantitatively characterize the crystalline anisotropy, where the longitudinal sound velocity follows the sequence 111 > 110 > 100. For laser-driven experiments where non-steady-state attenuation previously caused systematic underestimation, the HEL values are corrected upward by 8%–13%, reconciling discrepancies between different loading platforms.
    This hybrid approach enables the retrospective correction of non-ideal experimental effects through solely through data reanalysis, thereby providing high-precision dynamic constitutive parameters under extreme conditions without requiring specialized experimental configurations. The datasets presented in this paper are openly available at https://doi.org/10.57760/sciencedb.j00213.00274.

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