Disk Bending Shear Testing for Multi-Directional Composite Assessment

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Solution Overview

Problem

Conventional shear testing systems for composite laminate materials often limit evaluation to unidirectional laminar test specimens, restricting the assessment of shear properties in multiple directions, which is inadequate for complex composite structures like rotorcraft, aircraft, and windmill blades.

Innovation Solution

A disk bending shear testing system that supports samples at three or more separate locations around the periphery, applying a load orthogonal to the sample surface, and measuring shear testing data to determine interlaminar shear strength and stress, allowing for evaluation in multiple directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional shear testing systems use unidirectional laminar test specimens, then the testing setup is simple, but the assessment of shear properties in multiple directions is restricted

Engineering Contradiction:
Improveassessment of shear properties in multiple directionsVSAvoidtesting system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent transitions from unidirectional laminar test specimens to disk-shaped test specimens with multiple layers oriented in different directions. This dimensional change from 2D laminar to 3D disk geometry enables simultaneous assessment of shear properties in multiple directions (0 degrees, 45 degrees, and other orientations) within a single test specimen, thereby improving adaptability without requiring multiple separate testing setups

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If conventional testing systems use simple support structures, then the device complexity is low, but the representation of actual composite structure behavior is insufficient

Engineering Contradiction:
Improverepresentation of actual composite structure behaviorVSAvoidsupport structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs three separate support locations positioned at specific locations (such as 0 degrees, 120 degrees, and 240 degrees) around the periphery of the disk specimen, providing localized support that simulates actual structural conditions. This distributed support configuration better represents the complex stress states and failure modes encountered in real composite structures compared to simple single-point or two-point supports

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3336518B1Disk bending shear testing system
Publication Date: 2019.10.30 BELL HELICOPTER TEXTRON INC
  • EP3336518B1 patent drawingFigure 1
  • EP3336518B1 patent drawingFigure 2~3
  • EP3336518B1 patent drawingFigure 4A~4B

AI summary

A method for determining a shear property of a sample (108; 410; 412; 430; 440; 450; 460) includes supporting a sample (108, 400, 410, 412, 430, 440, 450, 460) at three or more separate support locations about a periphery of a first surface (110) of the sample (108, 400, 410, 412, 430, 440, 450, 460) in a testing fixture, the sample (108, 400, 410, 412, 430, 440, 450, 460) including a second surface (112) separated from the first surface (110) by a thickness (114), wherein the sample (108, 400, 410, 412, 430, 440, 450, 460) is axisymmetric about an axis that is orthogonal to the first surface (110). The method includes applying a load on the second surface (112) of the sample (108, 400, 410, 412, 430, 440, 450, 460) with a load applicator (104) in a direction substantially parallel with the axis, measuring, with a controller (106), shear testing data of the sample (108, 400, 410, 412, 430, 440, 450, 460) in response to applying the load, and determining, with the controller (106), a shear property of the sample (108, 400, 410, 412, 430, 440, 450, 460) from the measured shear testing data.