Barai Pallab, Sampath Rahul, Nukala Phani Kumar V V, Simunović Srđan
Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6359, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2010 Nov;82(5 Pt 2):056116. doi: 10.1103/PhysRevE.82.056116. Epub 2010 Nov 19.
This paper investigates surface roughness characteristics of localized plastic yield surface in a perfectly plastic disordered material. We model the plastic disordered material using perfectly plastic random spring model. Our results indicate that plasticity in a disordered material evolves in a diffusive manner until macroscopic yielding, which is in contrast to the localized failure observed in brittle fracture of disordered materials. On the other hand, the height-height fluctuations of the plastic yield surfaces generated by the spring model exhibit roughness exponents similar to those obtained in the brittle fracture of disordered materials, albeit anomalous scaling of plastic surface roughness is not observed. The local and global roughness exponents (ζ(loc) and ζ, respectively) are equal to each other, and the two-dimensional crack roughness exponent is estimated to be ζ(loc)=ζ=0.67±0.03. The probability density distribution p[Δh(ℓ)] of the height differences Δh(ℓ)=[h(x+ℓ)-h(x)] of the crack profile follows a Gaussian distribution.
本文研究了完全塑性无序材料中局部塑性屈服面的表面粗糙度特性。我们使用完全塑性随机弹簧模型对塑性无序材料进行建模。我们的结果表明，无序材料中的塑性以扩散方式演化，直至宏观屈服，这与无序材料脆性断裂中观察到的局部破坏形成对比。另一方面，弹簧模型产生的塑性屈服面的高度-高度涨落表现出与无序材料脆性断裂中获得的粗糙度指数相似的指数，尽管未观察到塑性表面粗糙度的反常标度。局部和全局粗糙度指数（分别为ζ(loc)和ζ）彼此相等，二维裂纹粗糙度指数估计为ζ(loc)=ζ=0.67±0.03。裂纹轮廓高度差Δh(ℓ)=[h(x+ℓ)-h(x)]的概率密度分布p[Δh(ℓ)]遵循高斯分布。
