MEASURING AND MODELING OF THE MECHANICAL PROPERTIES OF COMPOSITE BEARING PAD MADE OF PLASTIC MATRIX AND FINE BRONZE ELASTIC SPRINGS

The viscoelastic properties of the normal PTFE plastic and strengthened PTFEplastic for bearing pad are measured. The mechanical properties of the composite material forbearing pad, which is made of the aforementioned plastics as matrix reinforced by fine bronzeelastic springs, are modeled and relaxation modulus of the material are presented. The differencebetween these two kinds of PTFE is studied. The results show that the complex modulus of PTFEplastics for bearing pad is higher than that of normal PTFE plastics.

Bending stress of rolling element in elastic composite cylindrical roller bearing

A new structure design method of elastic composite cylindrical roller bearing is proposed, in which PTFE is embedded into a hollow cylindrical rolling element, according to the principle of creative combinations and through innovation research on cylindrical roller bearing structure. In order to systematically investigate the inner wall bending stress of the rolling element in elastic composite cylindrical roller bearing, finite element analysis on different elastic composite cylindrical rolling elements was conducted. The results show that, the bending stress of the elastic composite cylindrical rolling increases along with the increase of hollowness with the same filling material. The bending stress of the elastic composite cylindrical rolling element decreases along with the increase of the elasticity modulus of the material under the same physical dimension. Under the same load, on hollow cylindrical rolling element, the maximum bending tensile stress values of the elastic composite cylindrical rolling element after material filling at 0° and 180° are 8.2% and 9.5%, respectively, lower than those of the deep cavity hollow cylindrical rolling element. In addition, the maximum bending-compressive stress value at 90° is decreased by 6.1%.

Design and research of magnetically levitated testbed with composite superconductor bearing for micro thrust measurement

A high temperature superconducting(HTS)magnetically levitated testbed has been developed for the steady thrust measurement of miniature ion electrospray thruster.The structure of the testbed mainly consists of an HTS composite bearing,a magnetic shielding plate,an active electromagnetic brake and a laser displacement sensor.The steady thrust is described as a function of the equilibrium angle displacement of the floating frame.Furthermore,the mechanical behaviors of HTS composite bearing were studied via finite element simulation and experiments,which include the load capacity,levitation stiffness and background noise.The results show that the thrust testbed can keep in low noise and have a load capacity up to 4 kg.According to the ignition testing of the electrospray thruster,the thrust force of 25.2 m N was measured by the testbed,which is close to the design value of miniature ion electrospray thruster.