一个综合模糊裂纹和损伤的混凝土应变软化本构模型

本文研究就变软化材料的本构关系，提出了一个考虑损伤的粘塑性模型，损伤不仅影响材料的临界应力，而且影响材料的粘塑性，为模拟材料的应变软化行为，假设受损混凝土的破坏局部区域由模糊裂纹和损伤所统治，软化模量和局部区域尺度参量依赖于模糊裂纹扩展时释放的断裂能的参变量，用文中提出的模型计算了混凝土单轴压缩时不同应变速率下的瞬时应力应变响应以及等应力长期作用下的徐变，均得到很的结果。

A VISCOPLASTIC MODEL COMBINED DAMAGE AND SMEARED CRACK FOR SOFTENING OF CONCRETE

A viscoplastic model accounting for developing damage in concrete is proposed by assuming the rate of damage to be dependent on viscous strain and stress rates.The damage is measured by a scalar parameter affecting both the yield stress and the material viscosity.For a postcritical range of deformation,the localized mode combined damage and smeared crack occurs for strain softening of concrete.Two additional parameters in localized constitutive equations,softening modulus and thickness of the localized band, depend on the fracture energy Gf. The model is applied to simulate uniaxial concrete response.