Frangible Fastener Partial Release for Aircraft Winglets
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Solution Overview
Problem
Conventional frangible fasteners in unmanned aircraft often result in complete detachment of components during high-impact events, leading to damage and costly repairs, as well as disruption of electrical connections.
Innovation Solution
The development of frangible fasteners that partially release components when subjected to a threshold force, remaining connected through an inner fastener portion, preventing complete separation and maintaining electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional frangible fasteners completely detach components during high-impact events, then damage to the aircraft structure is minimized, but the components themselves are seriously damaged or destroyed and electrical connections are completely broken
Solution Approach 1:
The fastener is divided into two distinct portions: an outer fastener portion with frangible features that can break at a threshold force, and an inner fastener portion that remains intact to maintain component attachment and electrical connections. This segmentation allows the fastener to provide both protection against structural damage and preservation of component integrity.
Solution Approach 2:
The inner fastener portion acts as an intermediary element that remains engaged with both components after the outer fastener portion breaks. This intermediary structure prevents complete separation of components while allowing controlled separation, thereby preserving electrical connections and preventing catastrophic damage to expensive components.
2Ease of repair
If frangible fasteners allow complete separation of components, then repair costs for the aircraft structure are reduced, but repairing electrical connections becomes extremely expensive and time-consuming
Solution Approach 1:
By segmenting the fastener into breakable outer portions and intact inner portions, the design enables selective failure that protects both structural and electrical systems, reducing overall repair costs and time.
Solution Approach 2:
The outer fastener portion is designed to be discarded (broken) during impact events, while the inner fastener portion is recovered and remains in place to maintain electrical connections, avoiding the need for expensive electrical repair work.
3Strength
If the fastener completely breaks free, then the aircraft components can separate to minimize structural damage, but the delicate components are seriously damaged or destroyed
Solution Approach 1:
The dual-portion fastener structure with different fracture characteristics allows the outer portion to fail and absorb impact energy while the inner portion maintains component attachment, protecting delicate components from catastrophic damage.
Solution Approach 2:
The inner fastener portion is pre-positioned to provide a cushioning effect that prevents complete separation of components during impact, thereby protecting delicate components from the full force of the impact while still allowing sufficient separation to protect the main aircraft structure.
Data Source
AI summary
Frangible fasteners and associated systems and methods are disclosed herein. In one embodiment, for example, an unmanned aircraft can include a fuselage portion, a wing portion, and a winglet carried by the wing portion. The aircraft can also include at least one frangible fastener coupling the winglet to the wing portion. The fastener is coupled to only partially release the winglet from the wing portion when a force on the winglet exceeds a threshold value.