Flight Test Hinge Assembly Strain Measurement
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Solution Overview
Problem
Existing test hinge assemblies for aircraft components often require redesign or retrofitting to accommodate strain gauges, leading to increased costs and reduced accuracy in structural load validation measurements due to the need for larger pins or bolts, which is time-consuming and labor-intensive.
Innovation Solution
A test hinge assembly with a statically determinate design that positions strain gauges on external surfaces of interconnected beams and joints, allowing for accurate force measurement without the need for internal hollowing or redesign, using a monitoring system to calculate forces based on strain data from these gauges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gages are positioned inside hollowed-out portions of pins or bolts, then force measurement capability is achieved, but the pin or bolt must be redesigned with larger diameter to accommodate the strain gage, increasing manufacturing complexity and cost
Solution Approach 1:
The strain gages are relocated from the internal hollowed-out portions of pins to the external surfaces of the test hinge assembly's beams. This dimensional relocation eliminates the need to hollow out pins or bolts, maintaining their structural integrity while achieving force measurement capability through strain detection on external beam surfaces.
Solution Approach 2:
The test hinge assembly acts as an intermediary between the fastening members (pins or bolts) and the strain gages. Instead of attaching strain gages directly to pins or bolts, the assembly transfers forces through its beams, allowing strain gages to measure these forces on the beam surfaces without modifying the pins or bolts.
2Ease of manufacture
If larger diameter pins or bolts are used to accommodate strain gages, then strain gage installation is possible, but the accuracy of flight test structural load validation measurements is reduced
Solution Approach 1:
Strain measurement is moved from internal pin/bolt surfaces to external beam surfaces of the test hinge assembly. This allows strain gages to be installed on larger, more accessible surfaces without requiring larger diameter fastening members, thereby maintaining measurement accuracy while improving ease of installation.
3Measurement precision
If control surfaces are redesigned to accommodate test hinge, then strain gage measurement is enabled, but the process is time and labor intensive, increasing manufacturing and testing costs
Solution Approach 1:
The test hinge assembly is designed as a universal, modular component that can be applied to various control surfaces without requiring custom redesign of each control surface. The assembly includes standardized beams, connecting joints, and fastening member channels that can accommodate different applications, significantly reducing design and manufacturing time.
Solution Approach 2:
The test hinge assembly is pre-designed and pre-assembled with all necessary components (beams, connecting joints, fastening member channels) before installation. This preliminary preparation eliminates the need for time-consuming on-site modifications or custom fabrication, allowing rapid deployment across different control surface applications.
4Measurement precision
If standard pins or bolts are replaced with stronger, hollowed-out replacements, then strain gage accommodation is achieved, but the cost increases due to more expensive replacement hardware
Solution Approach 1:
The test hinge assembly serves as an intermediary structure that carries the strain gages on its beams rather than requiring modification of the fastening members themselves. This allows standard, unmodified pins or bolts to be used, eliminating the need for expensive hollowed-out or reinforced fastening members while still achieving complete force measurement capability.
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 solution provides accurate and efficient measurement of forces exerted on aircraft components, reducing the need for extensive revisions and increasing the accuracy of flight test data while maintaining compatibility with standard hardware.
Implementation Method 1
at least one strain gage secured to an outer surface of the at least one beam, wherein the at least one strain gage is configured to detect one or more strains exerted into the at least one beam
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A system for calculating forces exerted into an aircraft component (12) may include a test hinge assembly (10) and a monitoring system (18). The test hinge assembly (10) may be a triangular shaped assembly, and may include at least one beam 22, 24, 28, at least one connecting joint 26, 34, 42 having a channel (46, 48, 50) configured to receive and retain a fastening member, and at least one strain gage (60) secured to an outer surface of the beam(s) (22, 24, 28). The strain gage(s) (60) is configured to detect one or more strains exerted into the beam(s) (22, 24, 28). The monitoring system (18) is in communication with the strain gage(s) (60). The monitoring system (18) may be configured to calculate forces exerted into the fastening member(s) by analyzing the strain(s) (60) exerted into the beam(s) (22, 24, 28).