Spiral Flexure Bearing

Abstract

Flexure bearings are a key technology for many long-life, spacecraft-borne cryogenic refrigerator (cryocooler) designs. The bearing provides frictionless, non-wearing, linear movement and radial support for reciprocating machines. Since the maximum operating stress in the flexure is a controlling factor for the cryocooler operating life, this stress must be determined. The objective of the present work was to estimate the stresses in the flexure bearing under static and dynamic deflections.

A typical flexure bearing, which is a spiral-cut diaphragm, was considered. ABAQUS finite element code was used to characterize the flexure performance under static deflection. Analysis results of the flexure deflection correlate well with the measurement. However, the flexure is operated in the cyclic loading condition. Its responses under static and dynamic deflections might be different. DYNA3D finite element dynamic code was then utilized to analyze the flexure quasi-static and dynamic responses. Analysis results indicate that the peak dynamic stress in the flexure is 28% higher than the quasi-static response. Therefore, it is recommended that dynamic stress be considered in flexure fatigue life prediction.