An MDO Framework for the L-DED Manufacturing Process Applied to Propeller Blades

Abstract

A multidisciplinary design optimization (MDO) framework is presented for the Laser Directed Energy Deposition (L-DED) additive manufacturing process, applied to complex propeller blade geometries. The framework integrates physics-based models of powder–laser interaction, melt pool behavior, and path planning to link process parameters to key outcomes, including build time, track geometry, and defect risk. Dilution ratio, quantified as clad–substrate mixing, is used to predict defects such as lack-of-fusion and keyhole porosity. Manufacturability is further assessed via geometric quality metrics, including surface roughness and track inclination. These qualities, dilution, surface roughness, and track inclination, form a physically motivated scrap rate definition. The MDO problem minimizes build time under a scrap-rate constraint and is solved using a gradient-based approach. Model predictions are validated against experimental data, and sensitivity analyses quantify the influence of process and geometric parameters on build time and quality. Additionally the sensitivity of the MDO framework itself to thresholds settings and geometric inputs is examined. This approach establishes a physics-informed link between process conditions, defect formation, and manufacturability, supporting optimized selection of process windows and design tolerances for aerospace applications.