How can a sun umbrella be designed to withstand heavy rain?

Designing a sun umbrella to withstand heavy rain requires a combination of durable materials, innovative engineering, and thoughtful features. Start by selecting waterproof fabrics such as polyester or nylon with a high denier count, ensuring they are treated with water-repellent coatings. The frame should be constructed from sturdy materials like fiberglass or aluminum, which resist corrosion and provide stability in windy conditions. Incorporate a double-layered canopy design to enhance water resistance and prevent leakage. Additionally, include a built-in drainage system, such as small vents or channels, to allow rainwater to flow off quickly without pooling. Reinforced ribs and a robust central pole will further improve durability, ensuring the umbrella remains functional even during heavy downpours. By combining these elements, you can create a sun umbrella that excels in both sun protection and rain resistance.