Monolithic Composite Raised Features for Barely Visible Impact Detection
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Solution Overview
Problem
Composite materials like fibre-reinforced polymers face challenges in detecting impact damage, particularly Barely Visible Impact Damage (BVID), which can lead to unexpected failures due to the internal nature of damage and the difficulty in visual inspection, resulting in over-engineering and increased weight and cost.
Innovation Solution
A monolithic fibre-reinforced polymer composite component is manufactured with a main portion and raised features, where the raised features are designed to incur visually perceptible damage when subjected to impacts above a predetermined energy threshold, providing a clear indication of damage without compromising the main portion's functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If composite components are strengthened or reinforced beyond that required for their primary function to ensure detection of impacts below BVID threshold, then reliability is improved, but weight increases
Solution Approach 1:
The composite component is segmented into a main portion and one or more raised features. The raised features are deliberately designed to be more susceptible to impact damage than the main portion, so that they incur visually perceptible damage at lower impact energies. This segmentation allows the main portion to maintain its original design strength without additional reinforcement, while the raised features serve as sacrificial indicators of impact damage.
Solution Approach 2:
The raised features are designed with different local properties compared to the main portion - specifically, they have reduced impact resistance while maintaining the same material composition. This local quality difference ensures that the raised features fail first under impact, providing visual indication without compromising the overall structural integrity and weight efficiency of the component.
2Measurement precision
If means are added to detect impact damage below BVID threshold, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The raised features serve as self-indicating damage detectors. When subjected to impact above a certain energy threshold, they automatically incur visually perceptible damage that indicates the occurrence of impact. This eliminates the need for external sensing devices, complex inspection equipment, or additional monitoring systems, thereby maintaining simplicity while achieving improved measurement precision for impact detection.
Solution Approach 2:
The raised features provide visual indication of impact damage through changes in their physical appearance - such as cracking, chipping, or deformation that can be seen with the naked eye. This visual change mechanism replaces complex measurement instruments with simple optical detection, reducing device complexity while improving the ability to detect impact damage that would otherwise be invisible.
3Ease of operation
If visual inspection methods are used to detect BVID, then ease of operation is improved, but measurement precision deteriorates due to difficulty in detecting internal damage
Solution Approach 1:
Instead of trying to detect internal damage in the main portion directly through visual inspection, the invention inverts the approach by placing raised features that are designed to fail first and provide external visual indication of impact. The detection target is shifted from the hard-to-inspect main portion to the easily-inspectable raised features, thereby maintaining ease of operation while dramatically improving measurement precision.
Solution Approach 2:
The raised features act as intermediary indicators between the actual impact event and the inspector's visual detection. Rather than requiring direct visualization of internal damage in the main portion, the raised features serve as intermediate markers that translate internal stress and impact energy into externally visible damage patterns, bridging the gap between invisible damage and detectable signs.
Data Source
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AI summary
A method of manufacturing a monolithic fibre-reinforced polymer composite component 228 is provided. The method comprises providing a mould 206 comprising a main cavity 208 and at least one additional cavity 210 that extends from the main cavity 208; introducing a polymer matrix material 222 containing chopped fibre reinforcement into the mould 206 to fill the main cavity 208 and the at least one additional cavity 210 to form a monolithic fibre-reinforced polymer composite component 228 with a main portion 230 formed in the main cavity 208 and at least one raised feature 232 formed in the additional cavity 210 and extending from a surface plane of said main portion 230. The at least one raised feature 232 is arranged to incur visually perceptible damage when the component 228 is subject to an impact with an energy above a predetermined impact energy threshold and to resist an impact with an energy below the predetermined impact energy threshold.