Due to the effects of wind, waves and currents, as well as the pilot’s driving skills, the ship produces forces at different angles and speeds on the front of the dock when berthing, and some of the forces under the combination of angles and speeds affect the rubber fender And the dock has a greater destructive effect.
Cylindrical wharf fenders are suspended at the front of the wharf and are only restricted by the upward pull of the iron chain and the vertical force of the wharf wall. If the friction between the fender and the wharf front wall and the hull is considered, it is also constrained by the horizontal force along the wharf wall. According to the material, there are currently used rubber cylindrical fenders and polyurethane cylindrical pier fenders. Since the friction factor of the polyurethane fender is small (only 0.12), and the horizontal direction of the quay wall is the axial direction of the cylindrical fender, the shear damage caused by the friction force will not be large, so only the vertical compression force needs to be considered That's it.
For drum-shaped pier rubber fenders, due to its large volume and large vertical compression, its energy absorption is the largest among existing fenders, but the disadvantage is that it is easily affected by the side impact of the hull. It produces a large shear force, so it is necessary to consider the horizontal force. Due to the large volume of the ship and the arrangement of the fenders follow certain rules, the possibility of the drum-type pier fenders being directly subjected to horizontal thrust is very small, mainly due to the shearing force generated by lateral pressure and friction.
Using finite element software to simulate and analyze the compression of the fender, it can be seen that the lateral displacement of the fender caused by friction is greater than the pure compression, but the force of the ship on the rubber fender is both volume pressure and lateral friction. The volume change after compression of the side, and the lateral displacement caused by friction should be gradually reduced in proportion.
Judging from the current use of rubber fenders, it is difficult for cylindrical wharf fenders to meet the requirements for energy absorption; when the ship is docked normally, drum fenders can meet the requirements for energy absorption, but To prevent the drum-shaped fender from being damaged by shearing, steel chains should be added to its appropriate positions.