Structural optimization plays a crucial role in engineering by enhancing stability, minimizing stress concentrations, and improving material efficiency. Additive manufacturing, particularly vat photopolymerization with grayscale-masked stereolithography (gMSLA), provides new opportunities for optimizing material property distributions to achieve superior mechanical performance [1]. This study proposes an optimization framework that adjusts grayscale levels in 3D printing to control material properties and mitigate stress peaks exceeding yield stress. This approach integrates finite element analysis with a gradient-based optimization algorithm to optimize material property distributions, enhancing structural integrity. The optimized grayscale distributions are then utilized to fabricate components via gMSLA, and experimental validation confirms the effectiveness of the proposed method in reducing plastic deformation and improving structural performance. The results demonstrate the potential of grayscale optimization in additive manufacturing for producing lightweight, high-performance structures. REFERENCES [1] I. Valizadeh, O. Weeger. Rate-dependent energy dissipation of graded viscoelastic structures fabricated by grayscale vat photopolymerization. Smart Materials and Structures 33(6):065006 (2024), https://doi.org/10.1088/1361-665X/ad442a