Many machines include a small part designed to break when forces become dangerously high, much like an electrical fuse that blows when too much current flows. Known as a mechanical fuse or breakaway device, this part sacrifices itself to protect something more valuable, such as a drive shaft, building frame, or skier’s leg. These devices are typically designed through experience and trial and error, often resulting in complex assemblies that protect against overloads from only one or two directions. In this paper, we use topology optimization—a computer-guided method that determines where material should be placed within a structure—to design breakaway devices automatically. Our approach creates a “yield zone,” or region designed to fail as a whole at a specified load, making performance less sensitive to small modeling or manufacturing flaws and allowing the device to respond reliably to forces of different directions and strengths. The resulting one-piece structures could improve safety in bone-anchored prosthetic limbs, collaborative robots, and other systems where people and machines interact.