Study On The Adhesion Property Between Moulds With Biomimetic Coupling Non-smooth Surface And Soil

When we talk about the quality of the mould in the area of the wall material and the china material, the adhesion of the soil on its surface is the most important factor which effects the quality of the surface of the product. The adhesion can also increase the cost of servicing and reduce the manufacture efficiency. Along with the development of the industry of architecture and the manufacture of the brick, how to achieve anti-adhesion between china mould and the soil seems to be more important than before.This research based on the theory of engineering bionics and take advantage of modern mould surface processing technology, such as laser processing technology. This research paid more attention to the non-smooth property of earthworm, seemed it as the antetype, analyzed the reason of the outstanding anti-adhesion property of its surface and to know that it came from the coupling action between the non-smooth structure of its surface and the ropy body fluid with lubricate effect which excreted by its scarfskin tissue. In order to take advantage of the mechanism on improving the soil mould surface, this research produced the biomimetic non-smooth mould surface via processing units with different dimension and distributing on the surface by drilling and laser scanning. After that, make the surface of the mould ventilate through the hole on the unit and to achieve aeriform lubricate. Based on the coupling between aeriform lubricate and the biomimetic non-smooth surface, the biomimetic non-smooth soil mould with outstanding property of anti-adhesion could be made.This research thought about the effects of the property of the non-smooth mould surface, aeriform lubricate, the aquiferous quantity of soil and also the extra load on the normal adhesion force on the interphase between soil and mould, and considered that the coupling action between the property of non-smooth surface and aeriform lubricate was the primary reason which caused the reducing of normal adhesion force on soil/mould interphase. This paper also discussed the adhesion mechanism between biomimetic non-smooth mould and soil based on the different morphologies of contact interphase between tiny protruding unit of soil and the surface of mould. Based on the experiments and a series of analysis, this paper drew the conclusion as follows:1,This research imitated the non-smooth morphology of the surface of earthworm and the property of excreting lubricate fluid, and did some processings to the surface of soil mould which was made in 45# steel in order to improve its biomimetic property. In this way, this research got the soil mould with biomimetic non-smooth surface which also had different unit property. The adhesion force testing had testified that this kind of mould had outstanding property of anti-adhesion. It could also be found that the primary reason of improving the property of anti-adhesion was the coupling action between biomimetic non-smooth unit and the aeriform lubricate processing, which had the same reason with the outstanding anti-adhesion property of the earthworm.2,The effects of the property of biomimetic non-smooth surface on the property of anti-adhesion of the mould showed on the dimension and the distributing of the units chiefly. Based on the condition of this research, the adhesion force between soil and the mould with hole was lower than that between soil and smooth mould. Besides, along with increasing of the diameter of the hole in the unit, the adhesion force between the mould and the soil part would present the trend of increasing at first and then reducing, and the inflexion presented when the hole diameter was equal with 1.5mm. This phenomenon had no connection with destructive extent of interphase water film caused by hole. The effects of distributing of units on adhesion had also presented some rules. When the number of the rows and the lines of the stria units increased, the normal adhesion force between the mould and the soil interphase would reduce. If the non-smooth surface with larger number of rows and lines of units had the larger ratio of non-smooth area, the main reason of the reducing of the adhesion force would be the smaller contact area between the mould surface and the soil.3,The processing of aeriform lubricate had the remarkable effects on the anti-adhesion property of the mould. Different air pressure worked the different effects on adhesion force. In the same condition, aeriform lubricate would make the normal adhesion force between mould and soil interphase be lower than that without aeriform lubricate. The larger of the pressure of the aeriform lubricate, the lower of the adhesion force. The larger of the pressure of aeriform lubricate, the larger of the influencing extent of adhesion force caused by the difference of diameter of the hole and the distributing of units. All of these conclusion showed that the coupling action between aeriform lubricate and the property of non-smooth surface was the primary reason which caused the outstanding property of anti-adhesion on biomimetic non-smooth mould.4,The aquiferous quantity of soil was one of the most important factors which effected on the adhesion of soil. Based on the condition of this research, when the diameter of hole on the unit and the extra load had been fixed, the normal adhesion force between the soil and the mould interphase would present the trend of increasing at first and then reducing along with the increasing of the aquiferous quantity of soil. The inflexion of the trend presented when the aquiferous quantity was about 20%, and the adhesion force arrived the highest numerical value on this point. Contrastly, the lowest numerical value of the adhesion force presented when the aquiferous quantity was 24%. When the aquiferous quantity was lower than the critical value, the increasing of the aquiferous quantity would make the soil distort , in this way, the actual contact area between soil and the mould surface would be increased, which would cause the increasing of the adhesion force. When the aquiferous quantity was larger than the critical value, the weight of the interphase water film would make it beyond the controlling of the minus pressure on the interphase, and the water film would become a medium layer with the lubricate function, which would cause the reducing of the adhesion force.5,When the diameter of the hole and the aquiferous quantity had been fixed, along with the increasing of the extra load, the normal adhesion force between soil and the mould interphase would always increase, and the velocity of the increasing of the normal adhesion force would slow down after the value of the extra load had arrived at a certain value. The increasing of the extra load caused the increasing of the area and the thickness of the interphase water film, which was the main reason of the increasing of the adhesion force. But, when the area of the interphase water film would not increase any more, the continuous increasing of the load would only effect on the thickness of the water film. At the same time, because of the restriction from the aquiferous quantity, the velocity of the increasing of the thickness of the water film would be recuced, which caused the velocity of the increasing of the adhesion force also slowed down.6,The rule of the adhesion between biomimetic non-smooth mould and the soil interphase was connected with the state of the mould's contact interphase. When the water ring had unformed around tiny protruding unit on the contact interphase, the adhesion force was mainly influenced by the surface tension between interphase and the interphase material. The biomimetic non-smooth surface of the mould processed by laser technology had lower surface energy, which caused its less adhesion force. When the unattached water ring formed around the tiny protruding unit on contact interphase, the adhesion force was mainly influenced by the gravitation of the water ring and the contact angle of the water ring on the surface of the mould. The unit structure on the surface of the biomimetic non-smooth mould made the water could form larger contact angle on its surface, which was the main reason for the better anti-adhesion ability of the mould. When there were the consecutive water film among tiny protruding unit on the contact interphase, the rule of adhesion force between biomimetic non-smooth mould and the soil could be explained by the mechanism of division, the mechanism of eliminating the minus pressure, the mixed mechanism of division and eliminating the minus pressure, and also the mechanism of aeriform lubricate.