Effects of CFRP laminate thickness on the bending after impact strength
2008 (English)In: 13th European Conference on Composite Materials: 2-5 June 2008, Stockholm, Sweden, 2008Conference paper (Refereed)
This paper describes a series of experiments set out to explore the strength of bending loaded impacted monolithic composite panels with different thicknesses. Due to the aim to decrease manufacturing cost future structures are expected to have a higher degree of integration and complexity. More integrated structures give fewer articles and fewer steps in the manufacturing chain. Also the maximum thickness of laminated composite structures is increasing in aircraft structures. For example, the wing spars of the inner wings as well as the central wing box in modern aircraft are made from composite laminates with thickness exceeding 40 mm. As a consequence of this development there are more interlaminar loads (bending, transverse shear etc) within composite structures. Therefore the composite structures must sustain high out of plane loads (bending, transverse shear etc). To increase the potential and reduce conservatism during design there is a need to increase the knowledge regarding residual strength of out of plane loaded impact damaged composite structure. This study was launched as a first attempt to study the effects of bending load at different laminate thicknesses of a composite structure. Here two laminate thicknesses are tested, both exposed to the same impact threat. Accompanying tests in compression are performed and reported to allow evaluation of the full effects of bending. A limited fractographic analysis is also performed to study damage distribution after impact as well as after mechanical tests. It has been demonstrated that damage distribution through the thickness affects the bending properties of the laminate as the failure load was lower when the side with the largest delamination was loaded in compression. As expected it has also been demonstrated that the far field failure strain is higher at bending compared to compression loading.
Place, publisher, year, edition, pages
Research subject Polymeric Composite Materials
IdentifiersURN: urn:nbn:se:ltu:diva-35910Local ID: aa467200-c54d-11dd-80bd-000ea68e967bOAI: oai:DiVA.org:ltu-35910DiVA: diva2:1009164
European Conference on Composite Materials : 02/06/2008 - 05/06/2008
Godkänd; 2008; Bibliografisk uppgift: USB; 20081208 (ysko)2016-09-302016-09-30Bibliographically approved