Bolt joint under dynamic loading
 Metric thread : -
 Initial tensile stress : σi Rp0.2 
 Minimum value of clamping force: Fm kN
 Joint stiffness factor Cm=kb/(kb+km)
 
 tensile stress area At =π/4 d02 ; d0=(d2+d3)/2 mm2
 ultimate tensile strength Rm  MPa
 yield strength Rp0.2 MPa
 initial tensile stress σt = α Rp0.2 MPa
 load at yield F0.2 = Rp0.2 At kN
 initial preload Fi = σt At kN
 load fluctuation bolt Pb =F0.2 - Fi kN
 amplitude of bolt stress σat = Pb /At MPa
 endurance strength of the bolt σe MPa
 load fluctuation clamped material Pm= Pb (1-Cm)/Cm kN
 clamping force Fm = Fi -Pm kN
 Total load fluctuation P = Pb + Pm kN
Warning: Amplitude of dynamic bold stress > Endurance Strength: In infinite life or safe stress designs stresses higher then the endurance limit are avoided and a factor of safety is taken into account. Most rotating and oscillating components must sustain over 10^6 load cycles during service life and thus are to be designed for infinite fatigue life.
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