Bond strength degradation of adhesive-bonded CFRP composite lap joints after lightning strike

Wenhua Lin, Yeqing Wang, Spencer Lampkin, Srihari Ganesh Prasad, Olesya Zhupanska, Barry Davidson

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

1 Scopus citations

Abstract

Adhesive bonding to join fiber reinforced polymer matrix composites holds great promise to replace conventional mechanical attachment techniques for joining composite components. Understanding the behavior of these adhesive joints when subjected to various environmental loads, such as lightning strike, represents an important concern in the safe design of adhesively bonded composite aircraft and spacecraft structures. In the current work, simulated lightning strike tests are performed at four elevated discharge impulse current levels (71.4, 100.2, 141, and 217.8 kA) to evaluate the effects of lightning strike on the mechanical behavior of single lap joints. After documentation of the visually observed lightning strike induced damage, single lap shear tests are conducted to determine the residual bond strength. Post-test visual observation and cross-sectional microscopy are conducted to document the failure modes of the adhesive region. Although the current work was performed on a limited number of specimens, it identified important trends and directions for future more comprehensive studies on lightning strike effects in adhesively bonded composites. It is found that the lightning strike induced damage (extent of the surface vaporization area and the delamination depth) increases as the lightning current increases. The stiffness of the adhesive joints and shear bond strength did not show a clear correlation with the lightning current levels, which could be due to many competing factors, including the temperature rise caused by the lightning strike and the surface conditions of the adherends prior to bonding. The failure modes of the adhesive regions for all specimens demonstrate a mixed mode of adhesive and cohesive failure, which may be due to inconsistent surface characteristics of the adherends before bonding. The energy absorbed during the lap shear tests generally increases as the lightning current increases.

Original languageEnglish (US)
Title of host publication36th Technical Conference of the American Society for Composites 2021
Subtitle of host publicationComposites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021
EditorsOzden Ochoa
PublisherDEStech Publications
Pages37-49
Number of pages13
ISBN (Electronic)9781713837596
StatePublished - 2021
Externally publishedYes
Event36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021 - College Station, Virtual, United States
Duration: Sep 20 2021Sep 22 2021

Publication series

Name36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021
Volume1

Conference

Conference36th Technical Conference of the American Society for Composites 2021: Composites Ingenuity Taking on Challenges in Environment-Energy-Economy, ASC 2021
Country/TerritoryUnited States
CityCollege Station, Virtual
Period9/20/219/22/21

ASJC Scopus subject areas

  • Ceramics and Composites

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