Hits:

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:8

Page Number:1603-1611

ISSN No.:1000-6915

Abstract:Based on the meso-scale damage mechanism of quasi-brittle materials, the damage can be generalized into two aspects, 'the decrease of the effective cross-section' and 'the degradation of the elastic modulus of the effective region corresponding to the effective cross-section', which can be represented by rupture and yield damage modes respectively. The essence of failure process is the continuum accumulation and evolution process of the two damage modes. The dynamic behavior behaved by dry concrete can be essentially attributed to the inertia effect itself, which leads to the change of the breakage form and the two damage evolution process of materials. Ignoring the effect of water viscosity, by the hypothesis that the damage evolution rule of material under different strain-rate cases obeys a certain similarity, an increment-format dynamic damage constitutive model under uniaxial tension is proposed. Comparison of the prediction results with experimental data shows that it can accurately reflect and predict the dynamic damage characteristics in the uniform damage phase for concrete under the constant or variable strain-rate cases. Combining with the examples, the dynamic damage mechanism of materials is discussed from the view points of effective stress, nominal stress and the energy absorption capability. Two characteristic states, the peak nominal stress state and the critical state when appears macro-crack are distinguished; and the latter is proposed as the final failure point in the constitutive model. Treated by this way, not only the ductibility of the uniform damage phase of materials can be considered adequately, but also the size effect of constitutive model during the local breakage phase can be avoided to consider.

Note:新增回溯数据