接地冰川脆性断裂的动态相场模型
Dynamic phase-field model for brittle fracture in grounded glaciers
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中文总结 AI 辅助
针对接地冰川脆性断裂模拟的非物理问题，本文提出动态相场断裂模型，引入Kumar等人模型的新动态公式，考虑惯性可得到贯穿冰层的尖锐局域化裂纹，提升了冰川断裂模拟的合理性。
中文摘要 AI 辅助
冰川的断裂与崩解是冰体质量损失和海平面上升的关键驱动因素，但构建可预测模型仍具挑战性。接地冰川的断裂由重力驱动，通常在准静态线性弹性断裂力学框架内研究。本研究表明，在固定自重下的相场断裂框架内进行的纯准静态脆性断裂模拟，在冰裂隙萌生后会变得高度过驱动，产生非物理的扩散裂纹带增厚和弥散损伤模式。该问题源于重力驱动裂纹尖端前方的区域超出强度极限。为解决此问题，研究指出成核后的扩展本质上是动态不稳定性而非准静态过程，提出采用动态断裂公式。研究表明，考虑惯性会产生尖锐、局域化的裂纹，其可贯穿冰层厚度。作为第二个目标，本文提出了Kumar等人（J. Mech. Phys. Solids 2018）提出的相场断裂模型的新动态公式，该公式中弹性、惯性和重力贡献在断裂区域内被一致退化。
英文摘要
Fracture and calving of glaciers are key contributors to ice-mass loss and sea-level rise, yet predictive modeling remains challenging. Fracture in grounded glaciers is driven by gravitational forces and is typically studied within the framework of quasi-static linear elastic fracture mechanics. In this work, we show that purely quasistatic brittle fracture simulations within the phase field fracture framework under fixed self-weight can become strongly overdriven after crevasse initiation, producing unphysical thickening of the diffusive crack band and diffuse damage patterns. This pathology arises because gravity drives a growing region ahead of the crack tip beyond the strength surface. To resolve this, we show that the post-nucleation propagation is fundamentally a dynamic instability rather than a quasistatic process and propose the use of dynamic formulations of fracture. We demonstrate that accounting for inertia results in sharp, localized cracks that propagate through the ice thickness. As a second objective, this paper introduces a new dynamic formulation of the phase-field fracture model of Kumar et al. (J. Mech. Phys. Solids 2018) in which elastic, inertial, and gravitational contributions are degraded consistently in fractured regions.
