Bolted Joints — validation & limitations

What it calculates

• VDI 2230-1:2015 permissible assembly preload (F_M,zul) accounting for the tightening-method utilisation factor ν and combined tension–torsion von Mises stress
• Tightening torque (M_A) from thread-flank friction (μ, 60° flank angle) and underhead bearing-face friction (ISO 16047 / VDI 2230 Annex)
• Yield safety factor S_F = Rp0.2 / σ_red (von Mises) after VDI 2230-1:2015 with joint stiffness ratio Φ and the Table A8 tightening factor α_A
• Bolt fatigue safety factor via VDI 2230 §5.5.3 — size-dependent endurance amplitude σ_ASV (0.85·(150/d + 45), rolled threads, class-independent), compared directly to the alternating stress amplitude
• Metric coarse M3–M64, the ISO 261 fine series (M12×1.5 and the rest) and unified inch UNC/UNF — with the fine-thread fatigue reduction VDI 2230-1 §5.5.3 records, because its endurance equation is written for coarse 6g/6H threads
• Friction-grip shear capacity from the residual clamp load at minimum preload under full axial working load (VDI 2230-1 §5.5.6), after the preload lost to embedding
• Joint resilience from the geometry (VDI 2230-1 §5.1): bolt head, shank, free and engaged thread and nut, plus the clamped parts' substitute pressure cone — so the load factor Φ is a property of the joint rather than a slider, for through-bolted and tapped joints alike
• Embedding loss F_Z = f_Z/(δ_S + δ_P) per VDI 2230-1 §5.4.2.1 Table 5, by surface roughness, loading direction and number of interfaces — subtracted from the residual clamp, the slip capacity and the margin before the interface opens
• Bolt-pattern load distribution in 3D: any forces and moments, in-plane shear and twist plus out-of-plane tension and bending, mixed bolt sizes, asymmetric patterns (general bending with the product of inertia), and an exact rigid-plate contact model for non-preloaded joints — with the governing bolt handed to the VDI 2230 check
• Surface pressure under the head or nut on the annular bearing face (VDI 2230-1 R10), assembled and under load — with the effect of a washer, and a verdict once you give the clamped material's limit
• Thread stripping: the shear area of each thread against its own material (FED-STD-H28 / Machinery's Handbook, 60° ISO profile), which one goes first, and the engagement depth needed to develop the bolt itself — the check that matters for a tapped hole in aluminium or cast iron. Seven metric coarse sizes are tabulated at 6g/6H; for any other thread or fit you enter its four limit dimensions and the check runs on yours
• Bearing-type joints: bolt shear and plate bearing stress for shear carried by contact rather than friction

Standards this tool applies

• VDI 2230 — VDI 2230-1:2015 single-bolt checks (simplified) — preload F_M,zul, tightening torque M_A, yield safety S_F (von Mises), fatigue safety S_D, and friction-grip shear capacity for metric and unified-inch bolts.

Validation evidence — independent reference cases (0)

Each case runs the tool's engine on a worked example whose values come from a published source or a hand derivation from the cited equations, and an automated regression test asserts the engine against those values within the stated tolerance. "Conservative" means the engine is known to sit on the safe side of the reference and the test asserts that side. Sources are cited; their text is not reproduced.

No independent reference case is registered for this tool yet. Its engine is covered by the regression suite, but no published worked example has been reproduced end to end.

Limitations

Not checked by this tool

• Thread stripping of a tapped hole when no engagement depth is entered — Enter the engaged thread depth and the tapped material's strength to get the check (VDI 2230-1 section 5.5.5)
• Eccentric clamping (bolt off the joint's centre line, s_sym not 0) — Only a centred bolt is modelled; use the full VDI 2230-1 eccentric model or FEA for an offset bolt
• Prying from flange or plate bending in a bolt pattern — The pattern split treats the plate as rigid; prying can raise bolt tension — check the flange per VDI 2230 or FEA
• Load distribution in flexible multi-bolt flanges (VDI 2230-2) — Use VDI 2230-2 or FEA for flexible flanges and long bolt rows
• Self-loosening under transverse vibration — Not assessed; keep the joint from slipping and verify a locking element with a transverse vibration test (DIN 65151)
• Preload loss at elevated temperature (relaxation, creep) and hot strength — The thermal panel covers differential expansion only; use VDI 2230-1 temperature data for hot joints
• Hydrogen embrittlement and stress corrosion of high-strength or coated bolts — Not assessed; follow the coating and material rules for class 12.9 and coated fasteners (ISO 4042)