Compression after impact fatigue damage growth in CFRP – what does no-growth really mean?

Title

Compression after impact fatigue damage growth in CFRP – what does no-growth really mean?

 Author

Biagini, D. (TU Delft Structural Integrity & Composites)
Pascoe, J.A. (TU Delft Structural Integrity & Composites) ORCID 0000-0003-2771-8285
Alderliesten, R.C. (TU Delft Structural Integrity & Composites) ORCID 0000-0003-1882-5396

 Date

2023

 Abstract

Impacts on carbon fiber reinforced composites (CFRP) can produce a complex internal damage comprising multiple delaminations, which is hard to detect from visual inspection. This situation is known as barely visible impact damage (BVID). Considering that every airplane faces several impacts during its operational life, and that the majority of exposed surfaces in new generation aircraft is made of CFRP, there is a high chance that some aircraft will be flying with unnoticed impact damage. For this reason, BVID damage tolerance must be taken into account in design. The FAA and EASA dictate a no-growth design philosophy for BVID. Although multiple delaminations are present, BVID fatigue growth is usually assessed by measuring only the projected delaminated area with ultrasound inspections. This is done to simplify the damage description and because of the limitations in ultrasound inspection methodologies. In the present work, we show two cases of delamination propagation that are neglected following this procedure. Our experimental monitoring of delamination propagation with different ultrasound techniques shows a) growth inside the impact cone and b) faster growth of shorter delamination. The conclusion is that the projected area description is insufficient, since a no-growth in the projected area does not necessarily correspond to a no-growth in the actual damage.

 Subject

BVID
Damage Tolerance
Delamination
Fatigue
Ultrasound-scan

 To reference this document use:

http://resolver.tudelft.nl/uuid:118bf208-ba4a-4f16-b3bd-a3dae9c063f0

 Source

Proceedings of the 31st symposium of ICAF - the International Committee on Aeronautical Fatigue and Structural Integrity

 Event

ICAF 2023 – the 38th Conference and 31st Symposium of the International Committee on Aeronautical Fatigue and Structural Integrity, 2023-06-26 → 2023-06-29, Theater de Veste, Asvest 1, 2611 PK, Delft, Netherlands

 Part of collection

Institutional Repository

 Document type

conference paper

 Rights

© 2023 D. Biagini, J.A. Pascoe, R.C. Alderliesten
Files
PDF Biagini2023_ICAF.pdf 793.7 KB
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