): The portion of the external load that further stretches the bolt. Clamping Force Reduction (
The VDI publishes its guidelines under strict copyright. You will find many websites offering a “free PDF download,” but these are either:
FVmin≥FKR+(1−Φ)⋅FAcap F sub cap V m i n end-sub is greater than or equal to cap F sub cap K cap R end-sub plus open paren 1 minus cap phi close paren center dot cap F sub cap A Step 7: Check the Bolt Stress During Assembly
Graphically shows the interaction between bolt elongation and clamp plate compression. Assembly Preload ( FMcap F sub cap M vdi 2230 part 1 pdf
Select the final bolt size and strength grade (e.g., 8.8, 10.9, or 12.9). Verify the bolt is safe against yielding during assembly.
The standard requires solving multi-variable transcendental equations and complex geometric integrations for eccentric joints.
Accurate calculation of the substitution cones for complex geometries relies on the empirical tables validated by the VDI committee. ): The portion of the external load that
) generated during tightening. The equivalent stress must not exceed 90% of the bolt's yield strength ( Rp0.2cap R sub p 0.2 end-sub Step 11: Validate Bolt Stresses During Operation
Account for surface smoothing, embedding, and micro-settling of the contact surfaces after assembly. This reduces the effective preload available during operation. Step 8: Calculate Minimum Assembly Preload ( FM,mincap F sub cap M comma m i n end-sub
Detailed calculations for joints subjected to alternating operating forces. Assembly Preload ( FMcap F sub cap M
Fatigue strength requirements for joints subject to vibration or cycling.
: Used alongside VDI 2230 to derive highly accurate compliance values for asymmetric or complex 3D components. Conclusion