principal stress theory

principal strain theory

strain energy theory

maximum shear stress theory

Pre- tensioning helps to seal the pressure vessel

Pre- tensioning increase the fatigue life of the bolts

Pre- tensioning reduces the maximum tensile stress in the bolts

Pre- tensioning helps to reduce the effect of pressure pulsations in the pressure vessels

the maximum static radial load that can be applied without causing any plastic deformation of bearing components

the radial load at which $$90$$% of the group of apparently identical bearings run for one million revolutions before the first evidence of failure.

the maximum radial load that can be applied during operation without any plastic deformation of bearing components

a combination of radial and axial loads that can be applied without any plastic deformation