Bolt shear connection: mainly rely on the bolt rod and the hole wall to squeeze the force.
Bolt tensile connection: pre-tightening force mainly after bolt fastening.
When the rigidity of the connected members is large and the bolts are symmetrically arranged, each bolt will bear the tensile force acting at the joint on average; when the rigidity of the connected members is small, the flange of the joint will be bent and deformed to generate the lever force. .
In addition to shear and tensile forces, it is subject to other forces such as vibration, temperature, lateral stress (wind, flow, pressure, etc.), load changes, and so on.
What is the role of the U-bolt washer?
In the case where the bolt needs to be frequently disassembled, in order to protect the surface of the connected member from being scratched, it is generally necessary to place a flat washer at the position of the nut or the bolt head, so that the surface of the connected member is prevented from being scratched.
In some joints where the coefficient of friction is required, such as high-strength prestressed bolts, it is necessary to place flat washers on the nut end, because bolts, nuts and washers are provided by the same manufacturer in this case, and the bolt manufacturer needs to use the nut and The gasket is treated accordingly to ensure a consistent coefficient of friction between the nut and the gasket.
When the bolt strength is relatively high and the allowable compressive stress of the connected member is relatively low, in order to reduce the compressive stress of the pressure receiving surface of the joined member, it is generally required to add a flat washer.
In the bolt connection, the pressure transmission of the bearing surface of the bolt head or the nut is gradually enlarged in a flared shape, and the larger the bearing surface is, the smaller the compressive stress is, so that the flat washer can reduce the compressive stress of the contact surface of the connected piece. Ensure that the bolt connection is effective.