Shear Adhesion of Ice on Large-Sized Grooved Aluminum Surfaces

Abstract

Ice adhesion is important when designing aircraft anti-icing/de-icing systems. Major and minor grooves are common in the skin of aircraft. However, the effects of millimeter-scale grooves on ice adhesive strength have not been given due attention. Specimens with varying depths, widths, and numbers of grooves were fabricated by machining to investigate the ice adhesive characteristics of large-sized grooved aluminum surfaces. After the ice cube was frozen on the surface using a silicon mold, the adhesive force was measured using a self-assembled shear adhesive force setup. A correlation between groove size and apparent adhesive strength in the perpendicular loading direction was established based on the experimental results. Every 1% increase in the groove width ratio was associated with an 18.7 kPa increase in apparent adhesive strength. The increasing speed of the adhesion rapidly decayed as the groove depth increased. The increase in adhesion reached 99% of the maximum increase when the groove depth reached 0.8 times the width. The number of grooves had little effect on the adhesion when the total width of the grooves was kept constant. Stress distribution analysis was conducted using the finite element method, and the results were in accordance with the cracking phenomena in the experiments. The adhesive strength in the parallel loading direction was 30% lower than that in the perpendicular loading direction for all six chosen surfaces. This study is the first to propose a quantitative relationship between the surface textures of millimeter-sized grooves and ice adhesive strength. The loading orientation also had a substantial influence on adhesion. The results will serve as a valuable reference for future studies on ice adhesion on textured surfaces and for improving the performance of anti-icing/de-icing systems.