AD-enabled pythonOCC for CAD-based shape optimization

Abstract

pythonOCC is an open-source library extension that provides Python bindings for the widely-used Open CASCADE Technology (OCCT) geometry modeling kernel. It significantly facilitates the use of the CAD kernel in the context of automated processes for multidisciplinary design analysis and optimization (MDAO). To support gradient-based shape optimization, pythonOCC was differentiated using the AD tool ADOL-C in forward mode of AD and coupled with the differentiated OCCT in previous work. The AD-enabled pythonOCC and OCCT are integrated as a CAD plugin into a Python-controlled framework for high-fidelity MDAO relying on the FlowSimulator HPC ecosystem and OpenMDAO. The CAD plugin provides a robust metadata-supported mesh-to-CAD link and the computation of the so-called CAD sensitivities (e.g., derivatives of surface nodes w.r.t. design parameters). To demonstrate this workflow, a gradient-based shape optimization is performed using an aerodynamic test-case of reduced complexity.