Bolted joint under operating load — maximum operating load
Preload, stiffness-based load split and maximum permissible operating load for a preloaded metric bolted joint, from thread size, property class, preload fraction and joint stiffness factor.
Maximum operating load, P = Pᵦ+Pₘ43.14 kN
Clamping force, Fₘ = Fᵢ−Pₘ10.79 kN
Load variation, clamped material, Pₘ = Pᵦ(1−Cₘ)/Cₘ32.36 kN
Fatigue limit of the bolt, σₑ50.25 MPa
Bolt stress amplitude, σₐₜ = ½Pᵦ/Aₜ64 MPa
Load variation, bolt, Pᵦ = F₀.₂−Fᵢ10.79 kN
Preload force, Fᵢ = σₜ·Aₜ43.14 kN
Maximum preload force, F₀.₂ = Rₚ₀.₂·Aₜ53.93 kN
Preload stress, σₜ = σₜ′·Rₚ₀.₂512 MPa
Yield strength, Rₚ₀.₂640 MPa
Ultimate tensile strength, Rₘ800 MPa
Tensile stress area, Aₜ = π/4·d₀²84.26 mm²
Method & references
- Force-strain (preload) diagram of a preloaded metric bolted joint; maximum permissible operating load given a preload fraction and joint stiffness factor.
The computation is a literal port of the original client-side JavaScript from /calculators/e3_6c.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.