Thin-walled structures are well-known and have been used in many engineering and architectural applications thanks to their load-carrying behavior and free-form lightweight shapes. However, these structures are prone to external loads such as wind. Thus, the interaction of the coupled problem is crucial to be evaluated. Isogeometric Analysis (IGA) and its extension towards CAD-based B-Rep representation (IBRA) [1] have been established as an excellent tool for modeling and simulating trimmed multipatch shells. The application of IBRA in the body-fitted fluid-structure interaction (FSI), focusing on interface coupling via mortar mapping, has been initiated. Still, it has a disadvantage in the case of large deformations. In other ways, the embedded FSI framework, developed in [2], successfully deals with the problem. Combining this embedded approach with IBRA for shells introduces a novel approach, benefits from the exact representation. This contribution presents the topics in two-fold. First, the focus is on the formulation of CAD-integrated analysis of trimmed multipatch shell structures to develop a robust methodology for trimming by combining triangulation of the enclosed domain with moment-fitting and to revisit the weak imposition of the boundary conditions via the reconstruction of Nitsche’s stabilization factor and the suitable Lagrange multiplier field. The second part is to enhance the CAD-integrated analysis framework [3] in embedded FSI based on co-simulation approaches, including robust coupling schemes, suitable data transfer, and accurate transfer operators between different discretizations. The developments will be assessed by various benchmarks and real-world applications. REFERENCES [1] Breitenberger, M., Apostolatos, A., Philipp, B., Wüchner, R., & Bletzinger, K. U. (2015). Analysis in computer aided design: Nonlinear isogeometric B-Rep analysis of shell structures. Computer Methods in Applied Mechanics and Engineering, 284, 401-457. [2] Zorrilla, R., Rossi, R., Wüchner, R., & Oñate, E. (2020). An embedded Finite Element framework for the resolution of strongly coupled Fluid–Structure Interaction problems. Application to volumetric and membrane-like structures. Computer Methods in Applied Mechanics and Engineering, 368, 113-179. [3] Teschemacher, T., Bauer, A. M., Aristio, R., Meßmer, M., Wüchner, R., & Bletzinger, K. U. (2022). Concepts of data collection for the CAD-integrated isogeometric analysis. Engineering with Computers, 38(6),