AI 中文总结
该研究基于非仿射弹性与不可逆多体弛豫耦合，为金属和聚合物玻璃非线性变形建立微观本构理论，解释应力过冲等现象，通过拉伸指数弛豫指数等定量再现多材料实验曲线，建立统一微观框架。
AI 中文摘要
我们基于与不可逆多体弛豫耦合的非仿射弹性，为金属和聚合物玻璃的非线性变形建立了微观本构理论。该理论预测了从线性弹性到应力过冲、屈服再到稳定塑性流动的完整应力 - 应变响应。应力过冲源于原子/分子水平上应变驱动的机械连通性丧失引起的非仿射弹性不稳定性与结构弛豫相关的粘性耗散之间的竞争。对于聚合物玻璃，有限链可扩展性自然地解释了大变形时的应变硬化。通过应力或模量弛豫测量独立获得拉伸指数弛豫指数，并为该理论提供主要动力学输入。使用一小组具有物理意义的参数，该模型定量地再现了金属玻璃、聚碳酸酯、PMMA和环氧树脂在广泛应变率范围内的实验应力 - 应变曲线。这些结果建立了一个统一的微观框架，将非晶固体中的弛豫动力学、屈服、塑性流动和应变硬化联系起来。
英文摘要
We develop a microscopic constitutive theory for the nonlinear deformation of metallic and polymer glasses based on nonaffine elasticity coupled to irreversible many-body relaxation. The theory predicts the full stress--strain response, from linear elasticity through stress overshoot and yielding to steady plastic flow. We show that stress overshoot originates from the competition between a nonaffine elastic instability induced by strain-driven loss of mechanical connectivity at the atomic/molecular level, and viscous dissipation associated with structural relaxation. For polymer glasses, finite chain extensibility naturally accounts for strain hardening at large deformation. The stretched-exponential relaxation exponent is obtained independently from stress or modulus relaxation measurements and provides the primary dynamical input to the theory. Using a small set of physically meaningful parameters, the model quantitatively reproduces experimental stress--strain curves for metallic glasses, polycarbonate, PMMA, and epoxy resins over a broad range of strain rates. These results establish a unified microscopic framework linking relaxation dynamics, yielding, plastic flow, and strain hardening in amorphous solids.
