Experimental Study On Friction Coefficients Between Freshwater Ice And Various Materials

Ice damage is one of the biggest problems to the hydraulic structures and ships both on sea and other surface freshwater in cold area. In winter of northern China, many reservoirs will suffer freezing. Ice swells when heated which produce extrusion and friction force on the dam caused dike destruction. What’more, a lot of anti-slip measures are applied on the winter road, and the freshwater ice friction is also inevitable. So the studying of freshwater ice friction is very practical and necessary. There are two purposes of this research:For one thing, the large data of experiment can support the research on friction theory of ice and lay foundation for the mathematical modeling; For another, it will be useful to the maintenance works of dike and buildings around freshwater. For instance, we need to know a certain temperature when the friction damage of ice is worst, and cleaning work is necessary. The drag speed is also suitable when cleaning so that the dike could avoid the secondary scraping damages.Ice block is dragged by electrical motor to change the sliding speed on concrete, ice and plank with different temperatures, and then the friction coefficient can be got by testing friction force. And we get the conclusions:Firstly, when the contact area is very rough, such as concrete, the dynamic friction coefficient gets smaller with the factors of temperature, positive pressure and sliding velocity becoming bigger; the influence of both temperature and positive pressure to the static friction coefficient is interfered by velocity. Considered velocity’s influence separately, the static friction coefficient increases significantly for bigger velocity. Secondly, the contact becomes smooth, such as the ice-plank test, the dynamic friction coefficient increases with the temperature dropping or the positive pressure increasing, but the influence of sliding rate on dynamic friction coefficient is interfered by positive pressure; the higher temperature exhibits bigger static friction coefficient, and the velocity play a really big part in the influence of positive pressure to static friction coefficient, but the mono-factor-influence of velocity is not obvious. Thirdly, when the contact area is much smoother, such as the ice channel, the dynamic friction coefficient gets bigger at a higher temperature, and the influence of positive pressure and velocity to dynamic friction coefficient is same as the situation on plank; the impacts of temperature and positive pressure on static friction coefficient is interfered by startup speed seriously, and the mono-factor-influence of startup speed is complex too.The friction coefficients of freshwater ice on the different materials are different, and the value rank of friction coefficients on the various channels is:plank>concrete>ice. Friction mechanism depends on the structure and roughness of the contact material:when contact material is rough, such as the pair of ice and concrete, the adhesive friction theory is dominant; however contact area becomes smooth, the test on plank and ice, the water film theory could explain the friction problem easily, and we find that the adhesion of water film is greater which makes the friction bigger.