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Date of Publication:2007-01-01

Journal:岩石力学与工程学报

Affiliation of Author(s):建设工程学部

Issue:4

Page Number:670-681

ISSN No.:1000-6915

Abstract:A physical model composed by mesoscopic physical elements system is attempted to be established. By tracking its movement process, the complete damage and failure process of heterogeneous materials under quasi-statically uniaxial tension can be simulated. Based on the macroscopic response of quasi-brittle materials, the improved parallel bar system (IPBS) model which considers the equivalent relationship between effective stress and nominal stress of damage materials has been established. Further, considering the size effect in local softening phase, based on the hypothesis of tensile failure within the rupture process zone of limited length, the non-local damage physical model-double constitutive physical model (DCPM) is presented. The constitutive relation during the whole loading process is deduced; and the failure mechanism of the heterogeneous material is discussed from a novel viewpoint. The two characteristic states of damage material appearing during the loading process, when reaching the peak nominal stress and the macro-crack, respectively, can be distinguished. Regarding the later as the critical state, the whole loading process can be divided into the even damage phase and the local breakage phase. It is illustrated by examples that the model can simulate perfectly the macroscopic properties behaved by the quasi-brittle specimen under uniaxial tension. A novel material fracture theory, i. e. internal mechanical capability of material exerting mechanism theory, is proposed. It is considered that the whole damage process is controlled by this internal rule.

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