Compliant Antenna Mounting Structure for Thermal Mismatch Loads
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Solution Overview
Problem
Radar antennas face thermal mismatch stress and deflections due to temperature differences between the antenna structure and deployment mechanisms, which existing systems inadequately address, particularly in large span structures where conventional dual pin connections can lead to uneven load distribution and structural inefficiencies.
Innovation Solution
A mounting structure with first and second support arms having different load response characteristics, where the first arm is flexible parallel to the rotation axis and the second arm is stiff in all degrees of freedom, allowing for a 70/30 load share between them to reduce thermal mismatch stresses and maintain structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid dual pin connection is used to connect the antenna to the support structure, then structural strength and stability are improved, but thermal mismatch stresses and twisting deflections increase due to constrained thermal expansion
Solution Approach 1:
The first support arm incorporates a thinned section that changes the structural parameter of stiffness, creating a compliant region with lower stiffness in the thermal expansion direction while maintaining strength through strategic geometry modification
Solution Approach 2:
The thinned section creates a localized region of reduced stiffness within the first support arm, allowing differential thermal expansion at the connection point while the rest of the structure maintains its structural integrity and load-bearing capacity
2Stress or pressure
If a flexible connection is used to accommodate thermal mismatch, then thermal stresses are reduced, but structural strength and stability deteriorate due to increased deflection
Solution Approach 1:
The thinned section modifies the stiffness parameter locally to provide compliance for thermal expansion, while the overall arm geometry and material selection maintain sufficient structural strength for load-bearing requirements
Solution Approach 2:
The flexible region is localized to the thinned section, allowing thermal compliance only in the radial direction while maintaining structural rigidity in other directions to support operational loads
3Force
If conventional dual pin connections are used with one pin constrained axially, then lateral load resistance is improved, but uneven load distribution and structural inefficiency occur
Solution Approach 1:
The two support arms are designed with asymmetric stiffness characteristics - the first arm has a thinned section providing compliance while the second arm remains rigid, creating an asymmetric load path that distributes thermal and lateral loads more evenly between the two arms
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
This configuration effectively distributes thermal and lateral loads, reducing twisting deflections and maintaining structural strength, allowing for a compact and efficient connection of the antenna to the support structure, thereby mitigating thermal mismatch issues and enhancing the system's durability.
Implementation Method 1
stiffness about the rotation axis is approximately equal to reduce twisting deflections. Compliance is achieved by utilizing a thinned section of the first support arm, which acts as a beam structure and allows for a lower spring rate in the narrow dimension while preserving higher stiffness in the other two directions
Implementation Method 2
Over large spans this flexibility provides a leak path to reduce reaction forces that develop due to thermal mismatch between the antenna and support structures
Data Source
AI summary
Methods and apparatus for a mounting structure including a first arm having a first stiffness and a second arm having a second stiffness, wherein the first stiffness is less than the second stiffness in at least one degree of freedom. The first arm includes a flex region that can deflect in response to loading. In embodiments, the mounting structure can movably secure an antenna array to a pedestal.