混凝土局部损伤裂缝带模型研究

Local damage and crack band model for concrete

为消除混凝土开裂使有限元分析结果对单元网格尺寸产生的依赖性,在基于局部本构模型的材料非线性有限元分析中,建立了混凝土局部损伤裂缝带模型。结果表明:该模型所采用的三参数幂函数型拉伸损伤演化方程,可满足不同单元网格尺寸下应力-应变关系调整的需要;在局部损伤本构模型中引入断裂能和与单元网格尺寸相关的裂缝带宽度,可在保证断裂能客观性的前提下依据初始应力-开裂应变关系推导不同单元网格尺寸下的应力-开裂应变关系;提出基于异步粒子群智能算法的优化反演方法,可实现在有限元分析中依据应力-开裂应变关系自适应,从而确定不同单元网格尺寸下的模型参数。在ABAQUS软件平台上采用所建立的模型对算例进行了数值模拟,验证了模型的有效性与程序编制的正确性。

In order to eliminate the element size dependence of the cracking finite element analysis on concrete,a local damage and crack band model was proposed within the material nonlinear finite element analysis framework using local constitutive models.The requirement of adjusting the stress and strain relations under different element sizes can be satisfied by using the power-type tensile damage evolution equation with three parameters.The stress and crack strain relations under different element sizes,which can ensure the objectivity of the fracture energy,can be obtained on the basis of the original stress and crack strain by introducing the fracture energy and the crack band width related to the element size into the local damage constitutive model.Moreover,an optimization inversion approach employing the asynchronous particle swarm intelligent algorithm was proposed to adaptively determine the model parameters based on the stress and crack strain relation related to element size.The proposed model was implemented in ABAQUS,and the effectiveness of the model and the correctness of programming were validated.