Behavior of Composite Materials and Structures in Low Temperature Arctic Conditions

Advanced composite materials play vital structural roles in automotive, aerospace and marine industries. Drastic reduction in arctic sea ice region over the last three decades has opened new sailing routes which are more efficient and economical. This has resulted in the increased use of marine and naval vessels in extreme low temperature arctic conditions. The fundamental challenge of operating in such cold and harsh environment lies in the understanding of how materials and structures behave and perform in extreme low temperature. In this chapter, the behavior of composite materials and composite sandwich structures in low temperature arctic conditions is presented. Composite sandwich structure far exceeds classical composite laminates in terms of flexural capability and performance. In this work, we experimentally investigate the impact and post-impact compressive and flexural response of Divinycell H-100 foam core sandwich panel with woven carbon fiber reinforced polymer (CFRP) facesheets. Specimens were conditioned and impacted over a temperature range (from room temperature down to −70 °C). Results show that exposure to low temperature inevitably causes more severe damage in the specimens. Post-mortem inspection using x-ray micro-computed tomography revealed complex failure mechanisms in the composite facesheets (such as matrix crack, delamination and fiber breakage) and foam core (core crushing, core shearing and interfacial debonding).

Compression-after-impact (CAI) test results showed that low temperature environment severely influenced the residual strength of composite structures, leading to significant drop in CAI strength with decreasing test temperature. Post-impact three point bending test reveals residual flexural properties are more sensitive to the in-plane compressive property of the CFRP facesheet than the in-plane tensile property. Results also indicate that degradation of flexural rigidity of the sandwich composite panel strongly depends on existing damage state of prior impact test. Analogous to impact behaviour, specimens have much reduced flexural properties when exposed to extreme low temperature conditions.

Understanding material properties and structural performance would subsequently lead to new methods to enhance impact performance in arctic condition. The findings in this study would form fundamental understanding of composites behavior at extreme low temperature environment and the correlation of low temperature effects and dynamic damage behavior of composite sandwich structures.