Simulate With Real Geometry: Path-Based Modeling for Additive Applications

Abstract

Among directed energy deposition (DED) technologies, wire arc additive manufacturing (WAAM) is a widely used and effective approach. WAAM employs an electric arc to melt a consumable wire, while a robotic system strategically deposits weld beads to form the final component. This technique offers notable advantages, including the ability to manufacture complex metallic structures with multiple degrees of freedom, large build sizes, high deposition rates, and mechanical properties that are comparable to — or surpass — those of traditionally processed materials.1 Although WAAM technologies are often perceived as straightforward to implement, they introduce several practical challenges. Components produced by WAAM typically require extensive post‑processing to enhance surface finish, mitigate residual stresses generated during the build, and achieve the desired dimensional accuracy. As in other manufacturing workflows, WAAM also requires a geometric model that accurately represents the realworld shape. Conventional practices use these models to generate machine paths; conduct numerical simulations to predict strength, fatigue, and stress; and compare the nominal design with 3D scans of as-printed parts to evaluate dimensional deviations after manufacturing. In WAAM, however, the final shape of the manufactured part often deviates from the nominal design due to inherent characteristics of the additive manufacturing process in which parts are built by depositing multiple layers of material. The limitations of computer-aided engineering (CAE) software in capturing these effects during geometric modeling lead to errors in numerical simulations and pose challenges when using geometry as a reference. WAAM‑manufactured geometries frequently contain voids and geometric features that deviate from the original design, which can influence the structural and thermal behavior of the component. This white paper presents a path-based geometry modeling tool to address these issues. The tool uses the actual machine path and realistic bead profiles to produce a geometry model that more closely represents the manufactured outcome in terms of volume and geometric details. The benefits of this approach are demonstrated through simulations and experimental data. A complete Ansys Discovery™ 3D product simulation software to Ansys Mechanical™ structural finite element analysis workflow and the DED simulation features available in Ansys Mechanical software are also presented.