The tensile strength design of UAV-specific terminal cables must comprehensively consider dynamic loads during flight, environmental stresses, and performance degradation after long-term use. The core goal is to maintain structural integrity and functional stability under extreme operating conditions. As a critical component connecting drones to ground equipment or onboard systems, these cables must withstand the complex tensile forces generated during flight due to attitude adjustments, airflow disturbances, and sudden maneuvers. They must also adapt to harsh environments such as high and low temperatures, humidity, and salt spray that can erode material properties.
Regarding dynamic loads, UAV-specific terminal cables must withstand the transient tensile forces generated during vertical takeoff and landing, high-speed dives, and sharp turns. For example, during hovering operations, a tethered drone must withstand the repeated pull of its own weight and the lift of the drone. Insufficient tensile strength can lead to conductor breakage or insulation damage. Furthermore, the torque fluctuations generated by motor speed variations in multi-rotor drones during flight are transmitted through the cable to ground equipment, further increasing the stress complexity. Therefore, the cable's tensile strength design must simulate the multi-directional stresses experienced in actual flight, enhancing fatigue resistance through material enhancement or structural optimization.
Environmental adaptability is another key dimension of tensile strength design. High temperatures accelerate the aging of cable sheaths, reducing their flexibility and tear resistance. Low temperatures can cause embrittlement, making the cable more susceptible to breakage under stress. For example, cables for drones operating in extremely cold regions require low-temperature-resistant polyurethane or thermoplastic rubber outer sheaths to ensure sufficient tensile strength even at low temperatures. Furthermore, heat, humidity, and salt spray can corrode metal conductors and shielding, weakening the cable's overall structural strength. Therefore, tinning or the use of corrosion-resistant alloys is necessary to enhance resistance to environmental degradation.
Performance degradation over long-term use must also be factored into design considerations. Repeated bending and vibration can cause internal conductor breakage or insulation wear in cables, especially fine-stranded conductors, which are susceptible to microcracks under high-frequency vibration. For example, when agricultural drones fly at low altitudes, the cables experience continuous vibration due to friction with crops. If the tensile design doesn't account for this long-term stress, hidden damage can occur. Introducing fiber reinforcement or optimizing the stranding structure can significantly improve the cable's fatigue life and mitigate the degradation associated with long-term use.
Material selection and process optimization are direct means of improving tensile strength. Conductors typically use copper-clad aluminum wire or oxygen-free copper wire, balancing conductivity and lightweight requirements. Polyethylene or polyetheretherketone (PEEK) is used for the insulation layer, balancing wear resistance and high-temperature resistance. Polyurethane is the preferred outer sheath material due to its flexibility and weather resistance, while the addition of aramid fiber or ultra-high molecular weight polyethylene further enhances the cable's tensile strength. In terms of manufacturing, multi-layer co-extrusion technology ensures a tight bond between the layers, preventing strength loss due to delamination. Directed fiber reinforcement optimizes mechanical distribution, enhancing the cable's tensile strength in specific directions.
In practical applications, the tensile strength of UAV-specific terminal cables must be rigorously tested and verified. Tensile tests simulate structural response under extreme tension, flex life tests assess the effects of repeated bending on the conductor and insulation, and high- and low-temperature cycling tests verify environmental adaptability. For example, a certain type of tethered drone cable must withstand tensile forces exceeding 2,000 Newtons during testing and maintain stable performance in both high and low-temperature environments to ensure it will not fail due to environmental fluctuations during actual operation.
Industry trends indicate that balancing lightweighting and high strength will be a key design direction for future designs. The use of carbon fiber composite cables or high-density polyethylene sheaths can reduce weight while increasing tensile strength. The incorporation of intelligent monitoring technologies, such as embedded tension sensors, provides real-time feedback on cable stress status, enabling dynamic adjustments to flight parameters. These innovations not only extend cable life but also provide more reliable assurance for stable drone operation in complex environments.
