What effects does preload have on the bearing capacity of bolts?

1. Enhance the reliability of the connection
Appropriate preload can generate sufficient friction between the connection surfaces to prevent relative sliding of the connection under the working load, thereby improving the reliability of the connection.
2. Increase the fatigue life of the bolt
Appropriate preload can reduce the stress amplitude of the bolt under alternating loads, reduce the generation and expansion of fatigue cracks, and thus extend the fatigue life of the bolt.
3. Improve the anti-loosening ability of the bolt
Preload generates greater friction between the thread pairs, which helps prevent the bolt from loosening under vibration or impact loads.
4. Share the working load
Preload can pre-bear part of the working load, thereby reducing the force on the bolt in subsequent work and improving its bearing capacity.
5. Affect the static strength of the bolt
Excessive preload may cause the bolt to yield or even break during installation, reducing its static strength.
6. Change the stress distribution of the bolt
Preload will change the stress distribution of the bolt under the working load and affect the bearing capacity of the bolt.