Bolted joint stiffness ratio (joint stiffness factor)
Bolt stiffness, an assumed pressure-cone stiffness of the clamped material, and the resulting joint stiffness factor Cₘ=kᵦ/(kᵦ+kₘ) used elsewhere in bolted-joint load-sharing calculations.
Joint stiffness factor, Cₘ=kᵦ/(kᵦ+kₘ)0.25 [-]
Bolt stiffness, kᵦ=AE/lₘ1.13 1e9 N/m
Stiffness of clamped material, kₘ3.42 1e9 N/m
Cone diameter, d₂=1.5d18 mm
Cone diameter, d₃=d₂+lₘ·tan(φ), φ=30°30.12 mm
Method & references
- Bolt stiffness from a rod-in-tension model; clamped-material stiffness from a 30-degree pressure-cone frustum approximation.
The computation is a literal port of the original client-side JavaScript from /calculators/e3_6h.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.