A new polar ice-breaking method based on resonance theory was proposed and the mechanism was studied. Taking the infinite scale flat ice of 2m thickness in the polar region as an example, it is simplified as an elastic rectangular plate. Under the excitation of ice-breaking load, the vibration characteristic analysis of ice and numerical simulation of ice-breaking process are carried out, and the stress variation trend and failure mode of the ice with different excitation frequency, excitation position and excitation quantity are discussed. Results show that, when the excitation frequency is close to the natural frequency of ice, the resonance effect will be stimulated, which will lead to a significant enhancement of stress at the peak or trough of vibration mode. For the pre-breaking position, the effective directional ice-breaking can be realized by selecting the appropriate vibration mode, excitation position and excitation quantity. This paper verifies the feasibility and directivity of the polar resonance ice-breaking method, which provides reference for further research on the new polar ice-breaking equipment.
With the continuous promotion of polar scientific investigation and the upsurge of polar resource exploitation, methods of polar ice-breaking and ice-area channel opening have become a hot research issue (Bai, 2020). At present, relatively mature methods are excessively dependent on the weight of icebreaker and have high cost efficiency ratios. Therefore, the exploration of new polar ice-breaking methods with high capability has always been favored by researchers. In the actual icebreaking process, it is found that icebreaker and ice constitute a complex vibration system. Based on this, resonance ice-breaking method gradually comes into people's view.
Resonance ice - breaking method was first applied in road, aviation and other fields. In terms of road ice-breaking, Wang (2011) carried out the ice-breaking test by cutters and found that it is more efficient to break the ice with the same thickness by vibration method than static pressure method. Wan (2015) established the double-deck plate model on Kelxin foundation and derived the deformation and stress solutions under constant load and simple harmonic load, indicating that the deformation and stress of the plate under simple harmonic load are greater than those under constant load. Zhang, Li and Luan (2019) applied the resonant ice-breaking mechanism to the design of road de-icing devices. In aviation field, piezoelectric resonance deicing is used widely. Kandagal and Venkatraman (2005) used piezoelectric elements to find the resonant mode of cantilever plate in low frequency band, and selected the mode with the maximum shear stress for excitation, and finally obtained a good de-icing effect. Bai, Zhu, Miao, Li and Zhang (2014) took a planar aluminum plate as the research object, and explored the relationship among piezoelectric plate size, vibration mode and de-icing shear stress. They proposed a reverse mode that the vibration mode could be selected according to the freezing position, so as to design of piezoelectric plate size and layout. Villeneuve, Harvey, Zimcik, Aubert and Perron (2015) used a piezoelectric actuator to activate the resonant frequency of the plate, and drew a conclusion that the maximum displacement under given vibration mode can be obtained by locating the actuator at the ventral point and activating it synchronously with the ventral point. The result was applied to the structure of helicopter rotor blades.