This paper extends the Eulerian–Lagrangian–Lagrangian (ELL) method to solve the three-dimensional (3D) fluid–structure interaction (FSI) problems with flexible thin solids. The continuum-based (CB) shell element is adopted to model the flexible, thin-shell structure that undergoes large deformation. Several benchmarking problems, including a 3D cylinder-beam problem, vertical beam bending, and flapping flag, are solved to validate the present ELL approach incorporates the CB shell model. The results show that the ELL approach in this work has good agreement with references. A flapping butterfly with flexible wings is calculated to show the capability of the ELL to analyze more complex FSI problems in biomechanics.

本文扩展了欧拉-拉格朗日-拉格朗日（ELL）方法，以解决柔性薄固体的三维（3D）流体-结构相互作用（FSI）问题。采用基于连续体的（CB）壳单元对经受大变形的柔性薄壳结构进行建模。解决了一些基准测试问题，包括3D圆柱光束问题，垂直光束弯曲和拍打标志，以验证当前的ELL方法结合了CB壳模型。结果表明，本研究中的ELL方法与参考文献具有很好的一致性。计算出了具有柔性翼的拍打蝴蝶，以显示ELL分析生物力学中更复杂的FSI问题的能力。