Structural Design and Misalignment Compensation Performance Evaluation of Carbon Fiber Reinforced Polymer Diaphragm Coupling

The stiffness of diaphragm couplings directly affects the performance and reliability of mechanical systems. This study proposes a carbon fiber reinforced polymer (CFRP) diaphragm coupling. A finite element model was developed in ABAQUS and validated through torsional and axial stiffness tests. At a torque of 3000 N·m, the torsional stiffness error was 7.5%. At an axial displacement of 2 mm, the errors were 1.0% for axial compressive stiffness and 12.7% for axial tensile stiffness. Compared with a metal diaphragm coupling of the same external dimensions, the CFRP diaphragm coupling exhibits higher specific stiffness. The effects of key structural parameters on torsional and axial tensile stiffness were then investigated, followed by an analysis of the variations in both stiffnesses when diaphragm waist width and bolt hole diameter were varied simultaneously. The results show that waist width is the dominant factor affecting both stiffnesses. An appropriate combination of waist width and bolt hole diameter can balance high torsional stiffness with axial compliance. This study supports the structural optimization and engineering application of CFRP diaphragm couplings.