A scale-invariant cohesive crack model for quasi-brittle materials
A scale-invariant cohesive crack model for quasi-brittle materials
复制标题
DOI：
10.1016/s0013-7944(01)00085-6
复制
发表时间：
2002-01-01
影响因子：
5.4
通讯作者：
Cornetti, P
中科院分区：
文献类型：
--
作者：
Carpinteri, A;Chiaia, B;Cornetti, P
希勒堡虚拟裂缝模型是目前应用最广泛的混凝土结构损伤与断裂模拟模型。其独特的能力，以捕捉演变的开裂过程是伴随着它的简单性。然而，该模型并没有考虑到这种现象的某些方面，例如内聚规律中涉及的标称量的大小依赖性。这影响了模型的预测能力，当它被用来从小型实验室标本推断结果到全尺寸结构时。本文提出了一种不依赖于尺度的内聚律，克服了这些缺点，获得了一种独特的混凝土软化本构关系。通过假设损伤发生在试样内部的分形带中，名义应力、裂纹张开位移和名义断裂能变得依赖于尺度。因此，它们应该用分形量来代替，这是真正的材料常数。它们的分形物理维数之间的相互关系对无序性有很强的限制。通过改变运动学量的标度指数，可以得到从离散裂纹到涂抹裂纹的清晰过渡。分形内聚规律最终应用于一些拉伸试验数据，理论与实验结果吻合较好。2001爱思唯尔科学有限公司版权所有。
The fictitious crack model by Hillerborg is the most widely used model to simulate damage and fracture in concrete structures. Its peculiar capability to capture the evolution of the cracking process is accompanied by its simplicity. However, some aspects of the phenomenon are not considered in the model, for instance the size-dependence of the nominal quantities involved in the cohesive law. This affects the predictive capabilities of the model, when it is used to extrapolate results from small laboratory specimens to full-scale structures.In this paper, a scale-independent cohesive law is put forward, which overcomes these drawbacks and permits to obtain a unique constitutive relationship for softening in concrete. By assuming damage occurring in a fractal band inside the specimen, nominal stress, crack opening displacement and nominal fracture energy become scale dependent. Hence they should be substituted by fractal quantities, which are the true material constants. A mutual relation among their fractal physical dimensions puts a strong restriction to disorder. By varying the scaling exponents of the kinematical quantities, a clear transition from discrete to smeared cracking can be obtained. The fractal cohesive law is eventually applied to some tensile test data, showing perfect agreement between theory and experiments. (C) 2001 Elsevier Science Ltd. All rights reserved.