面向结构状态评估的多尺度损伤模型

Structural state assessment oriented multi-scale damage model

为了满足大跨结构健康监测和状态评估的需要,提出了计算结构损伤破坏的微宏观多尺度损伤模型.将结构微损伤变量定义为物质点处应力水平的函数,建立了非线性有限元模型,通过迭代求解来实现微损伤的耦合分析.为了考虑微损伤的累积效应,将结构的宏观损伤定义为微损伤的空间统计平均,选取均匀化遍历函数作为微损伤的空间分布概率密度函数,建立了宏微观损伤的关联模式,通过响应等效的方法来验证宏微观损伤关联模式的有效性.计算结果表明:耦合迭代求解技术可以降低微损伤分析过程中的网格敏感性;结构在均匀化宏观损伤下的响应与在非均匀微损伤下的响应吻合良好.采用多尺度损伤模型,可以有效实现结构的局部微损伤向均匀化宏观损伤的等效转换,有助于提高面向结构状态评估的有限元模型的计算效率.

A multi-scale damage model including micro and macro damage variables is presented to meet the necessity of state assessment of large scale structures.Micro damage variable is defined as a function of stress degree in material point.A nonlinear finite element method（FEM） is constructed to conduct coupling analysis of micro damage degree.To represent the cumulative effect of micro damage,macro damage is defined as a statistically homogeneous ergodic function of micro damage variable.Equivalent response method is used to verify the relationship between the micro damage and macro damage.Numerical results show that the coupling analysis technology with iterative process can reduce mesh sensitivity significantly,and structural responses under homogenous macro damage coincide well with those under heterogeneous micro damage.With transforming structural micro damage into equivalent macro damage,the developed multi-scale damage model can improve the computing efficiency of structural state assessment oriented finite element model.