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Compression after impact behavior analysis of composite thin laminates

News Process analysis and simulation

Compression after impact behavior analysis of composite thin laminates


Research project that includes two parts: a project funded by FIDAMC and Innovation Works called ILIA (Research and development of a new methodology of impacted laminates tests), and the Doctoral Thesis of Marina Remacha on Compression After Impact (CAI) in Carlos III of Madrid University.

Motivation and Aims

CAI ("Compression After Impact") test standard, ASTM D7137, only allows testing laminates greater than 4mm. Nevertheless, there are numerous aeronautical and aerospace applications with thicknesses even smaller than 2mm. The main objective was to design and validate a new CAI device that allows testing thin laminates.

Moreover, the developed device potential was analyzed and its range of application was estimated. Finally, finite element models with damage progression were performed in Abaqus and they were correlated with artificial delamination tests.

Main Activities

  • Damage analysis with several impact energies and for different thicknesses. Impact tests to determine the energy of barely visible impact damage.
  • Design and analysis of the new device consisting on a support with vertical ribs that helps to delay buckling without damage interference.
  • Developed device validation by testing specimens with thicknesses higher than 4mm and comparing the results obtained with this new device and with the standard one.
  • Results benefits check when thin laminates are tested.
  • Application range estimation.
  • Numerical models development and tests of specimens with artificial delamination to understand damage progression behavior and check the limit thickness of each device.

Conclusions and Industrial Application

In this project, a new CAI device to test thin laminates was designed and validated. While with the standard device it is not possible to test specimens thinner than 4mm; with the developed device, it is possible to test impacted specimens of less than 1.5mm thickness, because global buckling is delayed (although sublaminate buckling is allowed).

Furthermore, a numerical model with damage progression of low computational cost was proposed. It correlated adequately with the artificial delamination tests performed; and it was found that delamination progression occurs without interference.

Finally, a new device has been manufactured with the same concept, but improving materials, which is being used in several projects where it is necessary to perform CAI tests of thin composite laminates.



Scientific Paper

  • REMACHA, M.; SÁNCHEZ-SÁEZ, S.; LÓPEZ-ROMANO, B.; BARBERO, E.: A new device for determining the compression after impact strength in thin laminates. Composite Structures 127 (2015) 99-107

Patent

  • CASTRO, M.; REMACHA, M. Útil para ensayos de compresión después de impacto. (10/02/2012) PCT/ES2012/070087.

 

 



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