A vertical hydrogen bottle storage system suffered a chain collapse due to unforeseen vibrations. Technical analysis revealed that nearby compressors induced a fretting fatigue phenomenon in the frame connection bolts. This failure, modeled with SAP2000 and Ansys, shows how small oscillations can trigger progressive fractures in seemingly rigid structures.
Vibrational Modeling with SAP2000 and Ansys to Detect Fretting Fatigue 🔧
The engineering team used SAP2000 to analyze the global dynamic response of the frame to the compressor operating frequencies. The results indicated a close match with the natural frequency of the central module. With Ansys, a detailed vibrational analysis of the bolted joint was performed, simulating the relative micromovement between surfaces. The model identified areas of high cyclic stress concentration in the thread root, where cracks initiated. Comparison with laboratory tests, validated using GOM Inspect, confirmed that the friction wear pattern corresponded exactly to fretting fatigue, not conventional fatigue.
Lessons for Industrial Design under Hidden Dynamic Loads ⚙️
This case demonstrates that fretting fatigue is a critical risk in structures subjected to vibrations from adjacent machinery. To prevent it, it is recommended to isolate the compressors with base dampers and perform soil-structure interaction analysis in SAP2000. Additionally, bolts should be designed with treated contact surfaces to reduce the friction coefficient. Periodic inspection with a 3D scanner and GOM Inspect allows detection of incipient wear before a chain collapse occurs.
Which finite element simulation parameters should be prioritized to accurately model fretting fatigue in bolted joints subjected to vibrations in hydrogen storage systems, and how can these models be validated against a chain collapse?
(PS: Material fatigue is like yours after 10 hours of simulation.)