Design of a Lightweight UAV Frame Based on Topology Optimization Under Combined Static and Impact Loads

This study presents an integrated approach to designing a lightweight and structurally efficient quadcopter frame based on multistage topology optimization and comprehensive load modeling. Modern unmanned aerial vehicles increasingly require structural solutions that combine minimal weight with high durability and resistance to complex operational loads. To address this challenge, a digital model of a quadcopter frame was developed and sequentially optimized under various loading scenarios, including motor thrust, lateral forces, torsional moments, and dynamic impact conditions simulating a fall from height. The methodology incorporates stepwise application of loads, allowing identification of unloaded regions and optimal redistribution of material within the frame structure. Multiple design variants derived from topology optimization were subsequently evaluated using finite element analysis to assess stress distribution, structural stiffness, and failure risk under maximum anticipated loads. Special attention was given to the influence of impact braking distance on dynamic force magnitude, demonstrating the nonlinear dependence of impact loads on structural stiffness and highlighting the importance of controlled deformation zones in preventing critical damage. The results show that tubular frame configurations adapted from topology optimization achieve substantial weight reduction—up to 87% compared to the baseline model—while maintaining acceptable safety margins under both static and dynamic loads. The final design provides a balanced combination of manufacturability, structural efficiency, and compatibility with additive manufacturing techniques. The proposed approach contributes to the development of next-generation UAV structures optimized for real operating conditions and offers a scalable methodology adaptable to various unmanned aerial system architectures.