Application of equivalent stiffness theory to the corrugated diaphragm design method for diaphragm vacuum pumps

The diaphragm vacuum pump has a simple structure, reliable sealing, and oil-free operation, which is crucial for clean vacuum systems. However, its application is limited by the diaphragm fatigue life and achievable ultimate pressure. Corrugated diaphragms help reduce structural stress and improve fatigue life. However, their design theories and design methods have not been found or reported. This study proposes applying the equivalent stiffness theory to diaphragm morphology design. The results show that a diaphragm with lower equivalent stiffness has reduced structural stress and improved fatigue life. The effects of the amplitude, number, and projected length of corrugations on pump performance are simulated using the finite element method with ABAQUS software. The optimal ranges of diaphragm dimensionless parameters are proposed. A gradient corrugated structure is proposed to resolve the conflict between stress value and ultimate pressure. Finally, a design method for the corrugated diaphragm morphology based on the equivalent stiffness theory is proposed. This study provides a theory and a design method for the corrugated diaphragm, which is significant for diaphragm vacuum pumps.