What are jo-bolts primarily composed of for connection strength?

• A. Aluminum collar
• B. Steel bolt
• C. Corrosion resistant steel sleeve
• D. Both steel and aluminum

Answer: (D)

Jo-bolts are primarily composed of both steel and aluminum to ensure connection strength while also accommodating certain structural requirements. The combination of materials capitalizes on the strengths of each; steel provides exceptional strength and load-bearing capabilities, while aluminum offers a lightweight characteristic and good corrosion resistance.

Using both materials effectively enhances the overall performance of structural connections, particularly in aviation applications where weight savings are crucial without compromising the integrity of the connection. This is particularly important in the aerospace industry, where component weight can significantly impact fuel efficiency and overall performance.

Furthermore, the use of a steel bolt in conjunction with an aluminum collar or sleeve allows for optimal material compatibility, particularly when dealing with different metal types in structures. This dual composition helps prevent issues such as galvanic corrosion that may arise when dissimilar metals come into contact.

The other options focus on either steel or aluminum individually, lacking the benefit of combining both materials to achieve an ideal balance of strength and weight.