Short Beam Shear Test Fixture for Composite Coupons
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Solution Overview
Problem
Existing test fixtures for aerospace structures lack the ability to accurately test material coupons with high tolerance and reverse loading capabilities, particularly for composite materials, which are essential for verifying structural integrity.
Innovation Solution
A novel test fixture designed for load testing material coupons, featuring a short beam shear configuration that applies reverse loading and accommodates various lengths and widths while maintaining a specified length-to-thickness ratio, with adjustable grips and clamping mechanisms to secure coupons of different thicknesses and apply continuous clamping pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If typical prior art test fixtures are used, then testing can be performed, but high tolerance material coupons are required to accurately test each coupon
Solution Approach 1:
The patent changes the geometric parameters of the fixture, specifically the span length between supports, to accommodate coupons with varying thicknesses while maintaining the desired span-to-thickness ratio. This allows accurate testing without requiring high manufacturing precision on the coupons themselves
Solution Approach 2:
The fixture incorporates adjustable support positions that can be dynamically repositioned along the coupon length. This dynamic adjustment capability allows the fixture to adapt to different coupon thicknesses and maintain accurate testing conditions without requiring precision-machined coupons
2Adaptability or versatility
If typical prior art test fixtures are used, then single-direction loading can be applied, but the ability to reverse load test coupons is lacking
Solution Approach 1:
The loading mechanism is segmented into separate components: a movable crosshead assembly that can independently position loading points and a support system with adjustable spans. This segmentation allows the fixture to perform both single-direction and reverse loading by repositioning these segments, adding versatility without excessive complexity
Solution Approach 2:
The fixture is designed as a universal testing system that can perform multiple functions: single-direction loading, reverse loading, and accommodation of various coupon geometries. The movable crosshead and adjustable supports enable the same fixture to handle different test types without requiring multiple specialized fixtures
3Adaptability or versatility
If fixed grip positions are used, then simple fixture design is maintained, but the ability to accommodate various lengths and widths while maintaining specified length-to-thickness ratio is reduced
Solution Approach 1:
The grip positions are made dynamically adjustable along the fixture beams, allowing repositioning to accommodate different coupon lengths and widths. This dynamic adjustment maintains the required span-to-thickness ratio for various coupon sizes while adding only moderate complexity through standardized adjustment mechanisms
Data Source
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AI summary
A short beam test fixture (101) includes a housing (103), a first grip (113), and a second grip (115). The first grip and the second grip are each configured to clamp onto an upper surface and lower surface of a material coupon. The test fixture (101) also includes an upper input jaw (125) and a lower input jaw (127) each configured to clamp onto the material coupon near a center of the upper surface and the lower surface of the material coupon. The test fixture (101) is configured to load the material coupon in a first direction and a second direction. The first grip (113) and the second grip (115) are each configured to clamp onto the material coupon at a location which accordingly results in a desired testing ratio regardless of a variation in thickness of the material coupon.