An open-source framework for coupling non-matching isogeometric shells with application to aerospace structures

We introduce an open-source framework to directly analyze aerospace structures represented as collections of untrimmed NURBS patches, which is the representation used by NASA's Open Vehicle Sketch Pad (OpenVSP) for aircraft conceptual design. Airframes are modeled mechanically as Kirchhoff–Love shells and discretized isogeometrically for computational analysis. Coupling between separately-parameterized patches uses a slight modification of the penalty formulation proposed by Herrema et al. (2019) [31], which we verify using a similar suite of benchmark problems. Our open-source implementation leverages both advanced code generation through the FEniCS toolchain and efficient computational geometry operations through the Open Cascade modeling kernel. To demonstrate the framework's applicability to complicated industrial geometries, we perform stress analysis of the wing of an eCRM-002 electric vertical takeoff and landing (eVTOL) aircraft, with skin geometry designed in OpenVSP and internal stiffener geometry generated by an auxiliary tool. Source code for our non-matching shell analysis library PENGoLINS (PENalty-based GLuing of Isogeometric Non-matching Shells) will be maintained at https://github.com/hanzhao2020/PENGoLINS.