For determining the fatigue strength of bolted connection the method of virtual mean stress can be used.
where:
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σ a , τ a |
amplitude of normal (shear) stress [MPa, psi]. |
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σ e , τ e |
endurance limit at the constant strength [MPa, psi] |
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σ m , τ m |
mean cycle stress [MPa, psi]. |
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σ F , τ F |
virtual mean stress [MPa, psi]  |
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| Ψ |
factor of Haigh diagram narrowing [-] |
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depends on the joint material - recommended values - for traction and bending Ψ <0.15...0.3> |
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- for shear Ψ <0.1...0.25>. |