Hail impact testing of stitched carbon fiber epoxy composite laminates

Wenhua Lin, Yeqing Wang, Spencer Lampkin, Walker Philips, Samuel Prabhakar, Ryden Smith, Lincoln Whittington, Yin Fan, Rob Wolz, Wil Whittington, Hongjoo Rhee

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The hail impact response of the composite laminates is crucial in providing design guidance on the minimum allowable gauge thickness of the novel Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) composite panels for next-generation aerospace structures. In this work, we performed simulated hail impact tests for stitched and non-stitched flat carbon fiber epoxy composite laminate panels to study their different damage behaviors. All panels consist of a mid-bay area and four stiffening strips representing the aircraft composite structure stiffened with stringers. The tests were conducted using a gas gun and ice ball projectiles with a diameter of 40 mm. Different hail impact speeds (40 - 77 m/s), and hence different impact energies were imposed through tuning the pressure of the gas gun. After the hail impact tests, both visual observation and ultrasonic C-Scan were conducted to observe the surface damage and internal delamination. It was found that the matrix cracking occurs in every composite panel along the edges of the stiffening strip. In addition, delamination is found for both stitched and non-stitched panels in the mid-bay area and stiffening strips. The delamination area in the mid-bay area for the stitched composite panel is smaller than that for the non-stitched composite panel. The delamination in the stiffening strips could be caused by the stress concentration due to the geometric discontinuity between the skin and the stiffening strips. The observed different damage behaviors provided insights into the delamination arrestment capability of the stitched composites.

Original languageEnglish (US)
Title of host publicationProceedings of the American Society for Composites - 35th Technical Conference, ASC 2020
EditorsKishore Pochiraju, Nikhil Gupta
PublisherDEStech Publications
Pages731-745
Number of pages15
ISBN (Electronic)9781605956657
StatePublished - 2020
Externally publishedYes
Event35th Annual American Society for Composites Technical Conference, ASC 2020 - Virtual, Online
Duration: Sep 14 2020Sep 17 2020

Publication series

NameProceedings of the American Society for Composites - 35th Technical Conference, ASC 2020

Conference

Conference35th Annual American Society for Composites Technical Conference, ASC 2020
CityVirtual, Online
Period9/14/209/17/20

ASJC Scopus subject areas

  • Ceramics and Composites

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