A 1-million-liter stainless steel tank collapses at the base during a routine emptying process. The rupture was not instantaneous; the failure developed over months due to cyclic fatigue generated by changes in hydrostatic pressure between filling and emptying. In this technical article, we analyze how 3D modeling with Autodesk CFD and LS-DYNA allows identifying the exact point of crack initiation.
Hydrostatic stress analysis and CFD simulation 🧪
The tank base supports the greatest hydrostatic load, reaching pressures of up to 0.98 bars at the bottom when the tank is full. When emptying the wine, the pressure drops to zero, generating a load and unload cycle. Using Autodesk CFD, we modeled the fluid pressure profile on the walls and bottom. Then, we imported those loads into LS-DYNA to perform a finite element analysis. Stress maps revealed stress concentrations at the weld joint between the bottom and the lower ring, precisely where the crack initiated. The simulation showed that cyclic fatigue, with over 500 filling and emptying cycles, exceeded the fatigue limit of 304L stainless steel in that area.
Lessons from the simulation: design and prevention 🔧
The 3D scanning with Leica Cyclone of the collapsed tank confirmed that the actual geometry had a slight ovalization at the base, not detected in the original plans. The CFD and fatigue simulation demonstrated that this geometric deviation amplified local stresses by 30%. For future designs, it is recommended to include cyclic fatigue analysis from the engineering phase, using digital twin models that integrate periodic scans and load simulations to anticipate similar failures.
What coupled factors between fluid dynamics and structural fatigue explain the base collapse of a one-million-liter wine tank during a routine emptying?
(PS: Material fatigue is like yours after 10 hours of simulation.)