Abstract

Diaphragm fatigue fracture stands as one of the primary failure modes in hydrogen refueling station diaphragm compressors, urgently requiring systematic investigation into the mechanical properties and fatigue reliability of diaphragms under actual service conditions. However, due to the complex contact state between the diaphragm and the gas cavity cover plate (gas passage, gas hole)/oil cavity support plate and oil distribution plate (oil passage, oil hole), it is difficult to accurately obtain the stress distribution state of the diaphragm. In this study, we conducted material property experiments on the diaphragm to characterize its constitutive parameters. A refined numerical simulation model of the cover platediaphragm-support plate was established to analyze the mechanical properties of the diaphragm group under different conditions. The influence of diaphragm thickness on stress distribution and fatigue life was also explored. The results indicated that high stress distribution areas were mainly concentrated in the cavity transition zone and in the overlapping area of the diaphragm and gas passage/oil passage. The temperature inside the diaphragm compressor cavity had a significant impact on the stress level of the diaphragm. When the cavity temperature reached 300°C, the maximum von Mises stress reached 1286 MPa. The optimization results of diaphragm thickness indicated that when the diaphragm thickness was within the range of [0.3, 0.5 mm], the diaphragm was at a low stress service level; considering both the fatigue life and deflection performance of the diaphragm, the diaphragm thickness should be selected as thick as possible within the range of [0.3, 0.5 mm]. The numerical simulation model of the diaphragm compressor and the structural optimization design method of the diaphragm proposed in this article have significant engineering implications for improving the fatigue life of diaphragm compressor diaphragms.OPEN ACCESS Received: 02/03/2025 Accepted: 13/05/2025 Published: 14/07/2025