Reusable Frangible Joint for UAV Antenna Protection
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Solution Overview
Problem
Existing frangible booms on unmanned aerial vehicles (UAVs) are costly to replace due to damage during capture and retrieval, leading to increased part replacement time and expense.
Innovation Solution
A reusable frangible joint with hemispherical convex and concave surfaces secured by fasteners that shear under predetermined impact loads, allowing for easy removal and replacement of the fasteners for immediate reuse, and is designed to accommodate antenna booms to minimize signal interference and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frangible booms are used to protect antennas during UAV capture, then antenna damage is reduced, but part replacement cost and time increase
Solution Approach 1:
The frangible joint is divided into two separable hemispherical parts (convex and concave surfaces) that can be independently replaced. The fracture pin is a separate replaceable component that connects these parts, allowing the pin to be replaced without replacing the entire boom structure, thus reducing replacement time and cost while maintaining protective function
Solution Approach 2:
The fracture pin is designed as a disposable component that fails under impact load but can be easily replaced. The main boom structure with hemispherical surfaces is recovered and reused after pin replacement, separating the sacrificial element from the reusable structure, thereby reducing overall replacement time and cost
2Reliability
If frangible booms are used to minimize signal interference, then antenna performance is improved, but device complexity increases
Solution Approach 1:
The joint is segmented into simple hemispherical convex and concave surfaces that mate together, creating a straightforward geometric design. This segmentation allows the boom to maintain antenna positioning for signal quality while using simple, easily manufactured components that reduce overall structural complexity
Solution Approach 2:
The use of hemispherical surfaces for the joint provides smooth curved geometry that is structurally efficient and easy to manufacture. The spherical shape naturally distributes stresses and simplifies the mating interface between parts, reducing the need for complex fastening mechanisms while maintaining the boom's function of positioning antennas for optimal signal quality
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces the cost and time associated with replacing damaged frangible booms by enabling easy replacement of the fracture pin, maintaining antenna functionality and reducing signal interference during UAV capture and retrieval.
Implementation Method 1
A predetermined impact load applied against either of the first or second parts is configured to shear the fastener
Implementation Method 2
The concave surface is held in compression against the convex surface
Data Source
AI summary
A reusable frangible joint includes a first part having a hemispherical convex surface, and a second part defined by a reversely identical mating hemispherical concave surface. The convex and concave surfaces of the joint are secured and held together in compression until a predetermined applied load causes the joint to fail. The joint includes at least one replaceable fastener that rigidly secures and holds the respective concave and convex surfaces together. The fastener, designed to be the only part of the joint configured to fail, is sheared apart under the predetermined load, which results in separation of the concave and convex parts from one another irrespective of from which direction or to which part the impact load is applied. The failed fastener can then be replaced, wherein the frangible joint becomes immediately reusable, as having incurred no other damage by the impact load.