Systematic Calculation

🧮 在线计算器：VDI 2230 Bolted Joint Calculation — The full 14-step calculation chain (R0–R13), with six strength checks. 💡 Engineer, before blaming “poor bolt quality”, look at this real case — The connecting-rod bolts of a passenger-car engine failed catastrophically: the left bolt showed a typical one-sided bending fatigue fracture (a crescent-shaped fatigue region on the fracture surface), and the right bolt then broke suddenly from the force imbalance. Post-failure analysis found that the “culprit” was not the bolt material but insufficient preload. Because of assembly micro-embedding (Setzen), the preload dropped; under an eccentric service load, the connecting-rod interface opened slightly on one side, invisible to the eye (Aufklaffen), which caused a fatal alternating bending stress, finally initiating a fatigue crack at the shank root and a chain fracture. ...