: [ M_A = F_M \cdot (0.16 \cdot P + 0.58 \cdot d_2 \cdot \mu_th + \fracD_Km2 \cdot \mu_b) ] where (M_A) = tightening torque, (F_M) = preload, (P) = pitch, (d_2) = pitch diameter, (\mu_th) = thread friction, (\mu_b) = head friction, (D_Km) = effective friction diameter.
Scope and structure (typical contents of Part 1)
Estimate settlement (δ_Z) for all interfaces—threads, under-head, and clamped part joints—and its effect on diminishing preload over service life.
): The elasticity of the clamped materials. For complex geometries, VDI 2230 uses a substitutive "clamping cone" or "clamping cylinder" model. Step 5: Determine the Load Introduction Factor (
Calculate effective clamped volume and its stiffness (δ_P) using the replacement cone (or cylinder/cone) model. This is notoriously complex but critical for accurate load factor (Φ). vdi 2230 part 1 pdf
VDI 2230 relies heavily on the elastic deformation behavior of both the bolt and the clamped parts. When a bolt is tightened, it stretches like a spring, while the clamped components compress. This relationship is plotted on a joint diagram, which visualizes how external loads alter the internal forces of the assembly. 2. Elastic Resiliences ( δBdelta sub cap B δMdelta sub cap M Bolt Resilience ( δBdelta sub cap B
The you are considering (e.g., M12, 10.9) The type of loading (static or dynamic/cyclic)
Because VDI 2230 is a proprietary technical standard, official PDF copies are typically not available for free. You can find the authorized version through these primary distributors: VDI Official Website: is the primary source for the most recent revisions. DIN Media (formerly Beuth): As the central organ for German standards, offers the PDF in both German and English. Technical Libraries:
If your bolt fails at step R8 or R10, you must change the bolt size or material and restart the entire 13-step calculation from the beginning. : [ M_A = F_M \cdot (0
Part 1 (subject of this article) covers through-bolted joints and tapped blind holes. Part 2 focuses on multi-bolted joints (flanges, cylinder head bolts) with tightening and load distribution across multiple fasteners. Part 2 requires knowledge of Part 1.
The guideline focus on "high-duty" bolted joints, where the bolt is pre-tightened into its elastic range (often up to 90% of yield strength) to maximize efficiency and weight reduction. PCB Piezotronics Applicability: Specifically covers steel bolts with threads from and strength grades 8.8 to 12.9 Joint Geometry:
) 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
To ensure a joint never fails, an engineer following the VDI 2230 Part 1 Standard must embark on a rigorous 10-step calculation process: For complex geometries, VDI 2230 uses a substitutive
): Determining how much of the external load is absorbed by the bolt versus the clamped parts. Tightening Torque ( MAcap M sub cap A
High-strength bolted joints are critical components in mechanical engineering, automotive design, and structural applications. Ensuring their reliability requires precise calculation methods to prevent catastrophic failures caused by fatigue, loosening, or overloading.
While summary articles and specialized software (such as KISSsoft, MDESIGN, or internal corporate Excel spreadsheets) automate these equations, referencing the official remains essential for several reasons: