In this paper, a computational framework for simulating ductile fracture in multipatch shell structures is presented. A ductile fracture phase-field model at finite strains is combined with an isogeometric Kirchhoff–Love shell formulation. For the application to complex structures, we employ a penalty approach for imposing, at patch interfaces, displacement and rotational continuity and $C^0$ and $C^1$ continuity of the phase-field, the latter required if a higher-order phase-field formulation is adopted. We study the mesh dependency of the numerical model and we show that mesh refinement allows for capturing important features of ductile fracture such as cracking along shear bands. Therefore, we investigate the effectiveness of a predictor–corrector algorithm for adaptive mesh refinement based on LR NURBS. Thanks to the adoption of time- and space-adaptivity strategies, it is possible to simulate the failure of complex structures with a reasonable computational effort. Finally, we compare the predictions of the numerical model with experimental results.

在本文中，提出了一种用于模拟多面体壳结构中的韧性断裂的计算框架。有限应变下的韧性断裂相场模型与等几何 Kirchhoff-Love 壳公式相结合。对于复杂结构的应用，我们采用惩罚方法在面片界面处施加位移和旋转连续性和$C^0$ 和 $C^1$相场的连续性，如果采用更高阶的相场公式，则需要后者。我们研究了数值模型的网格相关性，并表明网格细化允许捕获延性断裂的重要特征，例如沿剪切带开裂。因此，我们研究了基于 LR NURBS 的自适应网格细化预测器-校正器算法的有效性。由于采用了时间和空间自适应策略，可以通过合理的计算工作来模拟复杂结构的失效。最后，我们将数值模型的预测与实验结果进行比较。