Vdi 2230 2021 Official

) based on the external loads and the required friction to prevent joint slip. Elastic Resiliences ( δPdelta sub cap P δSdelta sub cap S

| Step | Description | Key 2021 Update | |------|-------------|------------------| | 1 | Determine tightening factor $\alpha_A$ | Updated scatter bands for modern wrenches | | 2 | Determine required minimum clamp load $F_Kerf$ | New allowance for vibration loosening | | 3 | Calculate working load $F_A$ | Linear/non-linear load introduction factor $n$ refined | | 4 | Determine preload $F_M$ | Accounts now for temperature fluctuations | | 5 | Calculate assembly stress $\sigma_red$ | Inclusion of bending from non-parallel surfaces | | 6 | Verify bolt yielding $\sigma_red \le R_p0.2$ | Safety factor now depends on tightening method | | 7 | Calculate elastic resilience of bolt $\delta_S$ | Uses exact thread profile from ISO 68-1:2020 | | 8 | Calculate elastic resilience of clamped parts $\delta_P$ | New substitute cylinder angles for thin-walled tubes | | 9 | Determine load factor $\Phi$ | Includes eccentric clamping ($\Phi_en$) | | 10 | Determine preload loss $F_Z$ | New temperature relaxation term | | 11 | Minimum and maximum bolt force $F_Smin, F_Smax$ | Now includes statistical overlap with friction | | 12 | Dynamic stress amplitude $\sigma_a$ | Updated fatigue strength diagram (FKM guideline cross-reference) | | 13 | Surface pressure $p$ under head/nut | Limiting pressure for aluminum and plastics added | | 14 | Thread stripping check | New formulas for thin-walled nuts and tapped holes |

In earlier editions, $n$ was a discrete integer (1,2,3). The 2021 edition allows fractional $n$ based on FEA validation. For example, a joint where the load is introduced 30% under the head and 70% at the nut can now be modeled precisely. vdi 2230 2021

(Bolt Compliance): The amount the bolt elongates under preload. fPf sub cap P

): Calculating the minimum preload, considering the working load ( FAcap F sub cap A Considering the scatter of the tightening method. ) based on the external loads and the

The plates or parts being held together compress under the bolt's tension.

Ensure that the combined stresses during assembly (tensile stress from preload + torsional stress from the tightening torque) do not exceed the yield point of the bolt material. VDI 2230 specifies utilizing up to . Step 12: Validation of Bolt Stresses in Working State For example, a joint where the load is

The previous calculation for alternating stress (fatigue) was linear. The 2021 update introduces a approach (similar to the Palmgren-Miner rule).

The total stress on the bolt during tightening (combined tensile and torsional stress) and during operation must not exceed the bolt material's yield point ( Rp0.2cap R sub p 0.2 end-sub

, reducing the risk of underestimating the alternating stress on the bolt. 2. Updated Material and Friction Values

VDI 2230 follows a strict, multi-step engineering logic. A typical calculation includes the following phases: Step 1: Determine the Load Profile