# Effect of Ultrasonic Vibration on the Surface Adhesive Characteristic of Iced Aluminum Alloy Plate
## 1 Introduction  
In cold and humid environments, ice accretion often presents on the surfaces of rotating machinery, such as airplane wings and wind turbines, which degrades their performance and safety. For example, the icing on the surface of a wind turbine blade will change the airfoil profile and the weight of the blade, which are shown in Figure 1. As shown in Figure 1, ice accretion destroys the aerodynamic performance of the blade and reduces the power generation efficiency of the wind turbine. Meanwhile, it increases the weight of the blade, which shortens the life span of the wind turbine, and ice shedding threatens the safety of nearby people and buildings [1, 2, 3]. Similarly, the icing on the surface of the aircraft wing also reduces the reliability and safety of aircraft [4, 5]. Figure 1: Icing on wind turbine blades. [PERSON] [6; 7; 8] conducted an icing experiment of a wind turbine in a self-developed icing wind tunnel. The icing process and icing shape on the blade surface were examined, and an analysis method for the irregular icing shape was also proposed. [PERSON] [9; 10] calculated the process of ice accretion on the aircraft wing by simulation. The above-mentioned research findings lay the theoretical and experimental foundations for exploring the anti-icing and deicing methods in depth. Therefore, decreasing the adhesive strength of the ice and removing the ice from the machinery surfaces have high application value. At present, there are several kinds of methods being researched to reduce the adhesive strength of ice or remove it, including the electrothermal method, the fluid-thermal method, the pneumatic method, the electric-pulse method, the microwave method, the surface coating method, and the ultrasonic vibration method [11; 12; 13; 14]. Among these deicing methods, the electrothermal and microwave methods consume a significant amount of energy, while the fluid-thermal and pneumatic impulse methods have huge volumes and complex systems. In the surface coating deicing method, the coating easily falls off from the surface after a short working time, leading to the surface losing its deicing ability. The system of the electric pulse deicing method is complicated due to the high distribution density of the coil. In contrast, the ultrasonic deicing method has the features of consuming low energy, small vibration amplitude, long lifetime, light weight, no noise, simple structure, and easy installation and, therefore, can be considered one of the better deicing methods, especially for wind turbines. However, the deicing mechanism of it has not been refined and developed right now. The fundamental principle of it is to reduce the adhesive strength of the ice by generating shear stress at the adhesive interface between the ice and the substrate under the excitation of ultrasonic vibration. When the shear stress is higher than the adhesive strength, the ice falls off. [PERSON] [15] calculated the interfacial stress concentration coefficient (ISCC) and the vibration amplitude at the adhesive interface under a low-frequency excitation of a guided wave, and the distribution of the shear stress was acquired. [PERSON] [16] tested the ISCC of the iced composite material with an erosion layer and researched the deicing effect of the ultrasonic vibration in an experiment. [PERSON] [17; 18] simulated and tested the anti-icing and deicing effects of the ultrasonic vibration on an aluminum plate and the leading edge of an airplane wing in a wind tunnel. [PERSON] [19] investigated the deicing effect of ultrasonic vibration on independent lumpy ices on an aluminum plate using simulation and experiment. [PERSON] [20] explored the effects of shear stresses generated by ultrasonic vibration at the interface between the ice and the substrate through simulation and experiment. To maximize deicing efficiency, it is important to explore the effects of ultrasonic vibration on the adhesive characteristic of ice covering on the substrate surface.