): Calculate the minimum force needed to keep the joint tight, compensating for external axial loads, thermal loss, and embedding (surface roughness reduction). Determine Tightening Factor ( αAalpha sub cap A
Check the maximum stress under operational conditions. Ensure that the combination of maximum assembly preload, working load, and bending stresses does not cause plastic deformation. Step 13: Fatigue and Stripping Resistance Verification
2. Refined Calculation of the Deformation Cone (Deformation Volume) vdi 2230 2021
: Determining the additional bolt force caused by external loads. R7/R8: Stress Analysis
Identify axial loads, shear forces, and fatigue requirements. Determine Minimum Preload ( FM,mincap F sub cap M comma m i n end-sub ): Calculate the minimum force needed to keep
Due to the dozens of interdependent variables, manual calculation of VDI 2230 2021 can take hours and is highly prone to human error. Most engineering firms deploy specialized software tools—such as MDESIGN, KISSsoft, or proprietary CAD-integrated plugins—to automate the 2021 standard equations. These software packages pull verified material and friction data directly from the updated VDI databases, allowing rapid iterative testing of different bolt configurations.
At the heart of VDI 2230 is the (force-deformation diagram). When a bolt is tightened, it stretches like a tension spring. Simultaneously, the clamped components compress like a compression spring. Bolt Resilience ( δBdelta sub cap B ): The elastic compliance of the bolt. Component Resilience ( δMdelta sub cap M Step 13: Fatigue and Stripping Resistance Verification 2
Clarifications on determining the effective clamping length (
A key note from 2021: (determining required tightening torque) now mandates separate calculation of head friction and thread friction; no more lumped "total friction factor."
: Accounting for the inaccuracy of tightening tools (e.g., torque wrench vs. angle-controlled). R2: Minimum Clamp Force
With the rise of (higher vibration in EV motors), lightweighting (mixed material joints: aluminum to composites), and additive manufacturing (unconventional thread geometries), the 2014 edition showed gaps. The 2021 revision closes those gaps.