Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Experimental Study on Ice Breaking Mechanism of Ice-Breaking Air Cushion Platform
Ce Sun*, Yan Huang, Yufeng Tian, Jianqiao Sun
State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin, China.
Tianjin Key Laboratory of Port and Ocean Engineering, Tianjin University, Tianjin, Chinathen the ice body destroyed by the ACP. In high-speed ice breaking mode,
the ACP moves on the ice under high-speed, a large amplitude gravity
wave generated at the same time, and then damaged the ice. Kozin(Kozin V, Novolodsky I, 1990) a conducted deeply research on theresonant ice breaking mechanism of ACP. In this research, the structureof air cushion platform is simplified as a moving load, ice-water medium
is simplified into semi-infinite ice surface and semi-infinite water surface
models. The propagation characteristics of bending gravity wave on ice
surface and the possibility of ice breaking by resonance method arededuced. Zhestkaya and Kozin (Zhestkaya VD, Kozin VM, 2008)
combined the integral transformation method with the finite difference
hybrid algorithm to study the deformation process of ice under different
loads, and the deflection of ice under single point pulse is calculated. LuZaihua et al. (Lu ZH et al., 2014; 2012) studied the ice-breaking processof ACP at high speed on ice surface. LS-DYNA was used to simulate themovement of an ACP on ice surface at critical speed (11 kn) andsupercritical speed, and the variation law of ice wave induced stressexcited by ACP motion was obtained. Liu Jubin et al. (Liu JB, et al. 2012;2013] also carried out research on the wave generation problem of ice
surface. The Rankine source calculation method for solving ship wave
making was used to calculate the wave and ice deformation of ACP
sailing on ice at high speed, and the wave-generating resistance was also
solved. Based on the viscoelastic thin plate hypothesis and potential flow
theory, Li Yuchen et al. (Li YC, et al., 2017) simulated the sailingconditions of ACP at sub-critical speed, critical speed (11 kn) andsupercritical speed on ice surface. The wave propagation, stress variationand ice-breaking effect under different conditions are calculated andanalyzed. Based on the gravity flow theory, Xue Yanzhuo et al. (Xue YZ,et al., 2018) assumed the air cushion pressure under the ACP as uniformly
distributed load and carried out numerical simulation. The relationshipbetween air cushion pressure and maximum ice breaking thickness was
obtained, which will provides beneficial reference for the design work ofACP. Based on the elastic thin plate vibration differential equation andsimilar theory, Zhang Zhihong et al. (Zhang ZH, et al., 2014; Zhang ZH,et al., 2012) established the phase velocity and group velocity calculation
formulas for the propagation of vibration waveform when the ACP sails
on the ice surface. And obtained the phase velocity and group velocity
phases for the propagation of fluctuations in the ice-water system.
Following that, polyurethane (PU) thin film material is used to simulatethe ice surface by model experimental researching. These tests wereABSTRACT
To investigate the ice breaking processes of the ice-breaking air cushion
platform, a series of model tests in the ice tank of Tianjin University had
been carried out based on an actual ice-breaking air cushion platform
model. The regularities of ice breaking resistance varying with the hoverheight and navigation speed were finally established. And the key
mechanism of the high-pressure sub-ice air cavity was found, which
formed by the high-pressure air flow from the bottom of the skirt. Thisstudy provides necessary basic data for designing and safety operating of
ice-breaking air cushion platform.

KEY WORDS: air cushion platform, model test, ice breaking process,ice breaking resistance, hover-height

INTRODUCTION
The basic principle of air cushion platform (ACP) is utilizing the fan toformat high pressure air and then guiding them into the bottom of theplatform. The dynamic air cushion forms to lift the platform away fromthe support surface, such as ground, water or ice (Gao XY, et al. 2021;
Jiang YY, et al. 2021). The initial exploration of air cushion platform used
for ice breaking work began in the winter of 1971-1972. The researchersrefitted the air cushion platform ACT-100 into an Arctic drilling platformin the Great Nu Lake (or Great Slav Lake) in Yellowknife, Canada (ZhuSK, 2008; Howard SF, 1976). When moving the ACT-100, theresearchers found the platform having the ability to break ice, and about
0.76 m thick ice was breaking. Several ice breaking tests have been
carried out in Thunder Bay, Parry Bay, Toronto and Montreal around theArctic, and the ice breaking ability had been verified (Dickins DF., et al.
2008). From 1975 to 1976, the Canadian Coast Guard used the ACT-100
platform destroyed about 40 cm thick ice in thunder Bay which waspushed by icebreaker Alexander Henry. The CCGS Waban-Aki ACP
was also used to verify the ice breaking ability at low speed in the St.
Lawrence River of USA (Jones S, 2008). Hinchey and Colbourne(Hinchey M and Colbourne DB, 1995) summarized a lot of ACP ice
breaking results, and then the ice breaking mode of air cushion platform
is divided into low-speed ice breaking and high-speed ice breaking. In
low-speed ice breaking mode, a sub-ice air cavity will generate first, and1261