What is the difference between high strength bolt friction type and pressure type connection

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What is the difference between high strength bolt friction type and pressure type connection

2017/08/18 10:38

High strength bolt connection is a great tighten bolt rod inside the strong cohesion plate plate clamping piece, enough to attack a great deal of conflict, and then progress to connect all the sex and rigidity, when the shear force request in accordance with the planning and the different, can be divided into type high strength bolt conflict cohesion and high strength bolts pressure type two kinds, cohesion is the essential difference between the two limit condition is different, although it is the same kind of bolt, but in the computational method, request, there is a lot of in such aspects as the applicable scope is different. When shear planning, conflict type high strength bolt connection is outside shear to touch panel is supply by the bolt tightening force between perhaps the biggest conflict force as the limit condition, also is to ensure that the cohesion in all use period exterior-interior shear forces beyond the maximum force conflict. The plate will not have the relative slip deformation (the original amount of open space between the screw and the hole wall will always remain), and the connecting plate shall be subjected to elastic force. When shear planning, pressure type high strength bolt connection in outside to shear force beyond the biggest conflict, then by connecting plate deformation relative slip between attacks, until the bolt bar and hole wall touch, then cohesion depends on bolt shaft shear and pressure on the hole wall and the conflict between touch panel of the joint force, eventually with shaft shear or pressure on the hole wall damage as cohesive shear limit condition. Total return, conflict type high-strength bolt and pressure type high-strength bolt is the same kind of bolt in practice, but is planning is whether to think slip. The bolted bolt will not be able to slide, and the bolt will not accept the shear force. Once slip, the plan is to reach the damaged condition and the technology will be more mature. The pressure type high strength bolt can slide, the bolt also accepts the shear force, after all, the damage is equivalent to the usual bolt damage (the bolt is damaged or the steel plate is crushed).

It is used to see that the main components of the building structure are bolted together with high strength bolts. Usually bolts can be used repeatedly, high strength bolts can not be used again. High-strength bolts are usually used for lasting connections. The high strength bolt is the prestressed bolt, the conflict type USES the torque wrench to apply the rule prestress, the pressure type screws off the plum blossom head. The shear performance of the bolt is usually poor, but it can be used in the non-necessary structural parts. Usually the bolts should only be tightened. Usually the bolts are 4.4, 4.8, 5.6 and 8.8. High strength bolts are usually 8.8 and 10.9, of which 10.9 are in the majority.

The 8.8 is the same level as 8.8. The force performance and calculation method of the bolt and the high strength bolt are different. The stress of the high strength bolt pre-tensioning at the first is through its internal P, then by connecting a touch attack on conflicts between resistance to accept external load, and usually bolt is directly to the load.

More detailed, high strength bolt connection with construction of a brief, mechanical performance is good, removable, resistance to fatigue, and under the effect of dynamic loading is not loose strengths, is a promising way to cohesion.

High strength bolts are used to tighten nuts with a special wrench, which causes the bolt to have an infinite and controlled pretension, through the nuts and pads, and the same amount of pre-pressure on the connected parts. Under the effect of preloading along by cohesion force will attack on the surface of the larger conflict, obviously, only axial force is less than the conflict, component will not slip, cohesion is not damaged, this is the principle of high strength bolt connection.

High strength bolt connection is to rely on the conflict between a touch of the cohesion force to thwart the slip of each other, and touch the face to make enough force of conflict, it is necessary to progress artifacts of clamping force coefficient and increasing the component on the surface of the touch conflict. The clamping force between the members is done by applying the pretension to the bolt, so it is necessary to choose high strength steel production, which is also known as high strength bolt connection.

In the connection of high strength bolts, the magnitude of collision coefficient has great influence on bearing capacity. The experiment indicates that the conflict coefficient is primarily affected by the means of touch and the raw material of the components. In order to increase the conflict coefficient of the touch surface, it is necessary to use sandblasting and wire brushing to deal with the touching surface of the components.

There are two types of high strength bolt practice: conflict type and pressure type.

The principle of the shear force of the high strength bolt is that the shear force caused by the planning load is not beyond the conflict force.

The pressure type high-strength bolt is the planning principle for the rod body not to be damaged or not to be crushed