Load Transducer Lockup Assembly for Wind Tunnel Accuracy
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Solution Overview
Problem
Existing load transducers in wind tunnel environments face inaccuracies due to temperature transients and large thrust loads, which affect the measurement of forces and moments on test specimens.
Innovation Solution
A transducer body design featuring a sensor body with a rigid peripheral member and a central hub, connected by flexure components that concentrate strain and a biasing assembly to provide a bias force, along with a lockup assembly to inhibit movement, enhancing measurement accuracy and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the transducer uses a flexible sensor body to measure forces and moments, then measurement capability is improved, but the transducer becomes susceptible to temperature transients and thermal expansion causing measurement inaccuracies
Solution Approach 1:
The sensor body is divided into multiple discrete components (first sensor body portion, second sensor body portion, third sensor body portion) connected by flexure components. This segmentation allows each component to be optimized for specific functions while isolating the measurement mechanism from thermal effects.
Solution Approach 2:
The patent introduces a biasing assembly that applies a predetermined bias force to the sensor body, changing the operational parameters of the flexure components. This bias force compensates for thermal expansion effects and maintains measurement accuracy despite temperature transients in the wind tunnel environment.
2Force
If the transducer is designed to handle large thrust loads from large test specimens, then load capacity is improved, but measurement accuracy deteriorates due to excessive strain and deformation
Solution Approach 1:
The sensor body is segmented into multiple portions connected by flexure components, distributing the large thrust loads across multiple elements. This prevents excessive strain concentration in any single component while maintaining the ability to measure forces accurately.
Solution Approach 2:
The biasing assembly applies a predetermined bias force that optimizes the strain distribution in the flexure components under large thrust loads. This ensures that the strain remains within the accurate measurement range of the strain gauges even when handling large test specimens.
3Measurement precision
If the sensor body allows movement to measure forces and moments, then measurement capability is improved, but stability deteriorates due to unwanted movement and positioning errors
Solution Approach 1:
Different portions of the sensor body have different degrees of freedom and movement characteristics. The first, second, and third sensor body portions are configured with specific movement capabilities tailored to their measurement functions, while the lockup assembly provides stability when movement is not required.
Solution Approach 2:
The sensor body transitions between dynamic and static states. During measurement, the sensor body is allowed to move and deflect according to applied forces and moments. The lockup assembly can engage to inhibit movement when stability is required, such as during positioning or when measurements are complete.
4Stability of the object's composition
If the transducer uses a rigid structure to maintain stability, then structural stability is improved, but measurement accuracy deteriorates due to inability to detect strain and deformation
Solution Approach 1:
The transducer structure exhibits local quality with rigid portions providing overall structural stability and flexible portions (flexure components) providing strain detection capability. This allows the structure to be stable overall while having specific localized regions that deform measurably under load.
Solution Approach 2:
The sensor body combines rigid materials (for structural stability) with flexible elements (flexure components made of elastic materials). This composite structure allows simultaneous achievement of structural stability and strain detectability, as the rigid portions maintain geometry while the flexible portions deform in response to applied forces.
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 design improves measurement accuracy and stability by concentrating strain and providing a bias force, effectively mitigating the effects of temperature transients and large thrust loads, ensuring precise force and moment measurements in wind tunnel tests.
Implementation Method 1
each flexure assembly is configured such that forces transferred between central hub and the peripheral member concentrate strain at a midpoint along the length of each corresponding flexure component
Implementation Method 2
a biasing assembly connected between the support and the sensor body and configured to provide a bias force between the sensor body and the support
Implementation Method 3
a lockup assembly configured to selectively inhibit movement of the sensor body relative to the clevis halves
Data Source
AI summary
A transducer body includes a support comprising a pair of clevis halves; a sensor body coupled to each of the clevis halves, wherein the sensor body is disposed between the clevis halves and includes a generally rigid peripheral member disposed about a spaced-apart central hub, the central hub being joined to each of the clevis halves with the peripheral member spaced apart from each clevis half, wherein at least three flexure components couple the peripheral member to the central hub, and wherein the flexure components are spaced-apart from each other at generally equal angle intervals about the central hub; and a lockup assembly configured to selectively inhibit movement of the sensor body relative to the clevis halves.