相场断裂模型将裂纹近似描述为全局弥散标量场，通过求解偏微分方程模拟裂纹的成核与扩展，避免了不连续位移场中对裂纹几何形状述和裂纹尖端追踪的难题；在处理裂纹分叉、多裂纹、非均质材料和三维等复杂断裂模拟问题时具有显著的优势。然而，相场断裂模型需要在裂纹附近进行精细化的有限元网格剖分、计算规模庞大，因此，对计算能力提出了极高的挑战。本文基于子结构法和损伤识别，发展了一种适用于周期性结构脆性断裂的高效相场模拟方法。首先，根据周期性特征对结构进行分区并对子域内部节点进行子结构静态凝聚，降低有限元模型位移响应的维数；其次，根据离线（off-line）子域典型测试工况标定弹性应变能阈值，在线（on-line）断裂模拟过程中仅对阈值以上子域的内部位移和断裂相场进行解耦分析。一方面，利用结构的周期性特征，通过子结构静态凝聚降低计算规模；另一方面，根据能量阈值损伤识别，避免非裂纹扩展子域的重复计算消耗。

Phase field model for fracturing approximates the crack as a globally diffused scalar field. The crack nucleation and propagation are simulated by solving partial differential equations. This method avoids the numerical challenges in de-scribing and tracking cracks in the discontinuous displacement field. Hence, this method exhibits several advantages in modeling conventional challenging problems, such as crack bifurcation, multiple cracks, fracture problems within heterogeneous materials and three-dimensional cases. However, fracture modeling based on phase field method requires a refined finite element (FE) mesh near the crack, resulting in enormous computational costs. With substructuring and damage identification, this work proposes a highly efficient phase field method for brittle fracturing simulation of periodic structures. Firstly, the structure is partitioned into identical substructures upon its periodicity, and their internal nodes are statically condensed by means of substructuring. Secondly, an elastic strain energy threshold is identified by representative off-line tests of the substructure. Moreover, only the internal displacement and crack phase field of the substructures whose strain energies are above the threshold are further analyzed during the on-line fracturing simulation. Therefore, not only the structural periodicity contributes to the reduction of computational costs through sbustructuring, but also the non-crack propagation substructures are prevented from repetitive FE analysis by virtue of damage identification.