In this paper, the collocation-based isogeometric boundary element method (IGABEM) is combined with the isogeometric Reissner–Mindlin shell elements to conduct the mixed dimensional solid–shell coupling analysis. On the basis of taking advantages of the geometric smoothness and exactness of isogeometric analysis (IGA), this method can reduce the computational scale of the solid part and eliminate the procedure of constructing analysis-suitable volumetric discretizations. In addition, this method only needs to provide the surface CAD (computer-aided design) meshes of the whole coupling model, so it has great potential in achieving close link with CAD systems. For the coupling implementation, the stiffness formula of BE subdomains is formed by condensing the unknown tractions, which simplifies the implementation of coupling constraints. That is to say, only the displacement compatibility equations on the interface are required, without explicitly establishing the traction equilibrium conditions. Two coupling approaches are developed and studied. One is the collocation-based direct strict kinematic coupling based on the deformation hypothesis of the shell across the section, and another is the weak coupling formulation in an integral sense based on work equality. The accuracy and convergence properties of the presented coupling method are investigated through numerical examples including a complex impeller blade.

在本文中，基于搭配的等几何边界元方法（IGABEM）与等几何Reissner-Mindlin壳单元相结合，进行了混合尺寸的固-壳耦合分析。该方法在利用等几何分析（IGA）的几何平滑度和准确性的基础上，可以减少实体零件的计算规模，并消除了构建适合分析的体积离散化的过程。另外，该方法仅需要提供整个耦合模型的表面CAD（计算机辅助设计）网格，因此在与CAD系统实现紧密链接方面具有很大的潜力。。对于耦合实现，通过压缩未知牵引力来形成BE子域的刚度公式，从而简化了耦合约束的实现。也就是说，仅需要界面上的位移相容性方程，而无需明确建立牵引力平衡条件。开发和研究了两种耦合方法。一种是基于截面上壳体变形假设的基于搭配的直接严格运动学耦合，另一种是基于功相等性从整体意义上讲的弱耦合公式。通过包括复杂叶轮叶片在内的数值示例研究了所提出的耦合方法的精度和收敛特性。