The stress modes of bolts mainly include the following:
Pure tension: This stress mode is common in bolts that need to bear axial tensile force, such as engine cylinder head bolts.
Pure shear: This stress mode is common in bolts that need to bear shear force, such as engine flywheel bolts.
Tension + bending: This stress mode is common in bolts that bear tensile and bending forces at the same time, such as engine connecting rod bolts.
Tension + shear + bending: This stress mode is common in bolts that bear tensile, shear and bending forces at the same time, such as tire bolts.
Strength analysis and calculation of bolts under external load:
When the bolt is tightened and the external load is applied, the bolt and the connected parts will distribute the external load. The actual load of the bolt is the preload plus the external load. Factors affecting the actual load of the bolt under the external load state of the connecting sub-axis include the stiffness ratio (φ) of the bolt and the connected parts. The external load is usually distributed to the bolt at a ratio less than 1. For example, when the maximum value of φ is 0.5, the load proportion distributed to the bolt by the external load is the largest, which is half of the external load.
