Design, Fabrication And Static Or Dynamic Performance Of Experi-mental Study On Gas Foil Bearing

Gas foil bearings (GFBs) are composed of one or more layers of bump foilsand top foil with good complian t surface hydrodynamic bearing s. GFBs has thequality of reducing weight, high reliability, great design freedom, good hightemperature tolerance, low maintenance fee. At present, the GFBs has beensuccessfully applied on micro-turbo-machinery (MTM), i.e. ACM, CoolingTurbine, UAV Gas Turbine, turbocharger etc. GFBs have extremely wide de-velopment prospect and application value.The designing and manufacturing and commercial application of GFBs isstill largely dependent on the experience of the designer. Specially, the lack ofrelated research aimed at re searching the air foil bearing manufacture andperformance in china. This paper will combine the actual manufacturing processair foil bearings on the bearing design and manufacturing process are discussed,and based on the experiment of static characteris tics of bearing and dynamiccharacteristics, experimental study on the static and dynamic characteristics ofthe air foil bearings.The main research contents of the dissertation are as follows:（1） The designing and manufacturing of the first generation and thesecond generation bump foil type GFBs. Discusses in detail the bump foil de-signing and manufacturing process, mainly introduces the bump foil elasticstructure designing, bump foil stamping die designing and processing, foilmaterial and heat treatment process of bearing manufacturing processing.（2） Designing and building the GFBs static characteristic and dynamiccharacteristic experiment test rigs, the actual construction deficiencies in theprocess of the improvement and perfection, write the exciter co ntrol systemexperiment data acquisition system and dynamic characteristic experimentsusing NI data acquisition card and LabVIEW software.（3） By using the designed static characteristic and dynamic characteristicexperiment test rigs of bearing static stiffness and structural stiffness and equivalentviscous damping were studied. The results show that, the static stiffness of the bear-ing is nonlinear distribution is very strong, with increasing the bearing load capacityand static stiffness increased; bearing structure stiffness with increasing vibration frequency increases, and when the bearing vibration amplitude increases the stiffnessof the bearing is decreased; viscous damping bearing showed decreases gradually withthe vibration frequency and amplitude increasing trend.（4） Using the method of changing the size of the shaft neck radial clearanceon the same bearing on the static characteristics and dynamic characteristics of air foilbearings were studied. The experimental results show that, the load capacit y of bear-ing radial clearance of bearing large, static with decreasing the radial clearance ofbearing’s stiffness and the stiffness of the structure increased gradually; viscousdamping bearing radial clearance is reduced with increased first and then dec reased,which shows a small radial clearance on the damping characteristics were obtained atthe same time, larger bearing stiffness also at the expense of bearing.（5） According to the different bump foil elastic structure, different materials,different bump foil heat treatment methods and different load direction and otherfactors affecting bearing elastic structure properties were investigated under differentfactors, comparison of the static stiffness of the bearing and the structure stiffness andviscous damping effects, and provide experimental experience is important for thedesign and manufacture of bearing and the choice of foil material.