Study on the Failure Behavior of High-Density Polyethylene (HDPE) Water Storage Tanks in Service Environments

This study employs stereo microscopy, mechanical testing, infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), and thermogravimetric (TG) analysis to investigate high-density polyethylene (HDPE) water storage tanks. The results indicate that the step region of the HDPE tank interface withstands stress not exceeding 350 N. Fractured specimens exhibit oxidative substances such as carbonyl groups, with the oxidation induction time decreasing by 28.1% and the thermal decomposition temperature dropping by 20°C. The research demonstrates that structural defects, material oxidative degradation, and thermal history are the primary factors leading to failure. This study systematically elucidates the thermo-oxidative fracture mechanism of HDPE water storage tanks in automotive cleaning systems, revealing a coupled mechanical-chemical-thermal failure mechanism.