The key contact stiffness of the ship is the main piece of the ship. The ship is installed on the hull base by the connecting piece. Their stiffness is the performance of the mountain connector itself. The special foot dynamics have a very strong impact. And scare is often the weakest link in the mechanical system. The flashing is the method of their tight force on the anchor bolt to ensure that the bearing capacity of the bolt is fully utilized and the joint surface has the greatest rigidity. Otherwise, a connection failure may occur, which is caused by a weakening of the fastening of the joint surface under the cyclic load. This is caused by the mutual squeeze 1 or relative motion between the contact faces, and as a result, the self-locking performance of the threads is reduced.
We know that when the two metal faces are in contact, only a part of the microprotrusions come into contact. 1. The actual contact area is only a small part of the nominal contact surface. Usually, even if the precision of the finished precision is high, the actual contact area is also The contact contact area is 20301. The contact stiffness is the ratio of pressure to deformation. When the pressure is very small, there are only a few high points between the two contact faces, and the contact stiffness is low; when the pressure is large. These bulging points produce elastic or plastic deformation. The contact area is enlarged and the contact stiffness is also increased. However, the contact stiffness is related to the height of the degree of unevenness of the material and its distribution, so the contact stiffness between the metal faces is not fixed. That is; with, not public relations. The value is also difficult to calculate and the polymer such as epoxy resin has a contour contact area that is independent of the area of ​​the solid contact area. Therefore, it can be said that it is linear with 8.
Based on the above discussion, it is not difficult to compare the contact stiffness of several types of mainframes and hull bases currently used.
1 Adjustable gaskets are connected to this connection 23, 4 which are made of steel material. It is generally considered to adopt this structure. There is no need to scrape the gasket on the spot, but it does not prevent the main body from moving under the action of the anchor screw. This is because it is because the contact between the gasket and the mainframe base and the hull base is not tight enough; it is because the number of joint faces is increased to reduce the contact stiffness. It can be said that the more the joint faces, the lower the contact stiffness. . Therefore, in the past, the adjustable gasket connection is less used. Scared only to install small hosts.
1 base; 2 spherical block upper block; 3 spherical block lower block; 4 anchor bolts; 5 fixed spacers; 6 base 1 base; 2 circular block upper block; 3 circular block lower block ; 4 anchor bolts; 5 fixed spacers are also not used; male 4 thread adjustment ball and block 1 spherical surface; 2 spherical lower block; 3 seat ring; 4 stop screws 2 steel cast iron material made of rectangular gasket This type of connection is 5. The movable gasket is mainly intended to scrape its upper flat surface so that it fits closely with the lower plane of the base, the lower plane has been finished, and the upper surface of the fixed gasket can also be small. The flat plate is qualified for scratching, and the rectangular gasket of the main machine is labor-intensive and consumes a lot of man-hours, so it can also be ground or fine-finished instead of scraping. Even so, the contact area of ​​the two metal faces is only 20, which is small due to the contact of the conventional rectangular steel movable spacer. The pressure near the anchor bolt is usually large, and the pressure drops rapidly as the distance from the bolt increases. In the production practice, the gaskets that are recessed downward in the bolt hole circumference are not suitable and cannot be used.
Because of the pressing force, this kind of incorporation causes the rigidity on the kneading surface to be reduced in the region where the large stress is concentrated, and the fastening force is reduced.
I machine punch 2 foot snail, 3 know.肜 pad; 4 fixed heat block; 5 bushing 3 cast epoxy gasket to connect this type of connection 6. Epoxy gasket has a high coefficient of friction. When the machine is installed with a cast epoxy gasket, the requirements for the friend's surface of the base are not high. In particular, it is necessary to add and can carry out the work of the gasket on the irregular surface, and the machine can be firmly fixed when solidified after pouring. The base and the hull base panel are attached together, so the contact area of ​​the base gasket is 100, so the stress distribution is uniform, and the stress concentration of the steel gasket due to uneven stress distribution is avoided. In this way, it is extremely difficult to slip between the base and the base, and there is theoretically no wear. Therefore, the foot screw is not easy to loose. Ring, Resin Pad When the main unit is working, the expansion force of the epoxy gasket is limited by the fastening bolts, which increases the tension of the bolt and improves the stability of the gasket. In fact, statistics on the use of a large number of real ships have confirmed that the resin gasket is reliable. The same is true for 10,000-ton ships.
1 hexagonal lock nut 2 hex nut; 3 extension sleeve; 4 base; 5 cast epoxy pad; 6 base; 7 anchor bolt 4 Conclusion From the above analysis, we can see that several hosts are currently used. Connected with the hull stern, in the case of the same type of mainframe, the contact stiffness of the epoxy gasket connection is the largest, followed by the rectangular gasket, and the smallest is the training gasket connection. Adopted.
Ni Yan, He Zukun, Sun Juncai. Metal surface properties and surface modification. Dalian Dalian Maritime University Press, 1998 21 Chen Fu. The use of claw 120-person cast epoxy gasket. Shipbuilding JHv19972 trillion increased to 22.7 trillion in 1998. From 1999 to 2002, the demand for natural gas in the world increased at a rate of 2.5 per year, and a new field in the Far East. Countries such as Thailand, India, China, and the Philippines will have tremendous growth in the medium and long term. The World LNG 10 fleet has been climbing the current fire section with the increase in shipping volume; the ship has a capacity of more than 100,000 small vessels operating between other Asian countries and Japan. By the end of 1998, the number of ships in the global 0 fleet exceeded that of ships, with a total volume of 400,000 and 131 ships operating for 40 years. In the period of renewal, the new one in the future; the demand for ships is expected to rise.
With the development of world trade liberalization, the global economy has become increasingly physical. After China joined Jia 10, it marked that China's opening up to the outside world has entered a new stage of development. Foreign-funded Chinese-foreign joint ventures will surely enter the coastal areas of China. Inland rivers are engaged in liquefied gas transportation, and China's liquefied gas water transportation industry will also be more competitive with the inner 1; small field competition. The shipping capacity will be gradually increased, and the ship will be adjusted to 1 Duping. In 2001, the domestic 1 water transport market research and analysis. Water transport 2 correction å·. Strive to regulate the market to safeguard common interests. Water transport technology 2000103 Luo Longjun, Fan Xiuqi, Wang Weizhao. Liquefied gas carrier safety knowledge and operation.
Dalian Dalian Maritime University Press, 1999, page 7
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