The stiffness of elastomeric diaphragm in pneumatic springs

Abstract

Abstract The design of pneumatic springs applied in precision vibration isolation platforms requires an accurate mathematical model. Many validation experiments have shown that neglecting the effect of the diaphragm on the response of a isolator can lead to a significant error between the observed and predicted behavior. This paper modifies the standard pneumatic spring model by considering the effects of the diaphragm on stiffness. A theoretical model for diaphragm stiffness is presented. The model equates the inner and outer rings of the diaphragm into two segments of composite material subjected to unidirectional stretching. The elastic modulus and stiffness of each part of anisotropic materials were obtained using the theory of composite mechanics, combined with the working conditions of the diaphragm. Finally, the dynamic stiffness experimental platform was built to verify theoretical model. The result indicates that considering the stiffness of elastomeric diaphragm, the error is reduced from 27.33% to 7.5%.