滚动轴承振动与噪声关系的灰色研究

以灰色系统理论为基础,通过实验,研究6201和6203轴承振动与噪声的关系。振动用加速度有效值描述,噪声以声压级表示。实验数据处理结果表明,轴承振动与噪声的关系不明显,并具有很大的不确定性。因此,不宜用轴承的振动代替轴承的噪声,应单独研究轴承的噪声问题,制订轴承噪声标准和相应的工艺标准。      

整体离心叶轮叶片的振动可靠性分析

述及了整体离心叶轮的结构及其故障模式特点,在强迫振动放大系数模型的基础上提出了离心叶轮叶片的振动可靠性分析方法,结合固有频率灵敏度分析的叶片共振相干分析,通过厚度控制来调整整体叶轮叶片的固有频率,控制强迫振动放大系数使之避开危险性共振或强迫振动,给出了一实际算例,算例及试车试验表明本文方法是有效的。      

基于压电式加速度计的振动测量原理及应用

阐述了利用压电式加速度计、电荷放大器、动态信号分析仪进行振动测量的原理及应用。     

复合材料翼面结构的自振和颤振分析及优化设计

 建立复合材料翼面结构的有限元静力分析模型。采用柔度方法作静力模型到动力模型的转变,进行结构固有特性分析,并研究了频率约束下的优化设计。运用亚音速马蹄涡——振荡偶极子格网法计算了谐振翼面的三维非定常气动力,并对两种真实翼面进行了颤振分析,结果令人满意。推导了非定常气动力和颤振响应参数对设计变量的导数,研究了颤振约束下的优化设计。     

太阳电池阵布局对微小卫星结构特性影响

通过对比某型号微小卫星两种体装式太阳电池阵布局及连接方式,从结构响应灵敏度的角度分析了结构的阻尼对整星顶板太阳敏感器测点加速度响应的影响程度。同时对两种方案整星的正弦振动试验结果对比分析,结果显示:减少侧板固定连接点且增加电池片数量的方案使其顶板部分测点响应超出了设备试验条件,且比初始设计方案测点的响应高出了27.1%,纵向和横向一阶频率均有不同程度的降低。因此,从结构特性的角度来看,初始设计方案更为合理。     

振动试验力限条件设计复杂二自由度方法研究

力限振动试验可以缓解振动“过试验”现象。计算力限条件是进行力限振动试验的前提。本文介绍了力限振动试验的基本原理,给出了计算力限条件的基本过程,详细推导了设计振动试验力限条件的复杂TDFS方法,为今后力限振动试验在国内的应用提供技术支持。     

卫星虚拟振动试验系统研究

卫星虚拟振动试验可以预示试验结果,为试验设计提供参考。文章首先对振动试验系统进行分析,根据试验设备的不同和信号数据的传输规律,将系统分为5个分系统;研究各系统的特性,确定其在虚拟试验系统中的仿真方法;然后重点阐释台体系统和振动控制系统的计算机仿真方法;最后将虚拟振动试验结果与实际振动试验结果进行对比分析,结果显示两者基本一致。     

卫星振动试验中推力的估算方法

准确预估规定试验条件下卫星振动试验所需推力对于试验的设计与实施具有重要意义。文章在常规卫星振动试验需用推力估算方法的基础上,结合具体的小卫星应用实例提出了支反力分析预示法和类比相似结构卫星推力的方法来估算卫星振动试验需用推力。通过与实际振动试验推力数据对比,文章给出了卫星振动试验需用推力估算方法的实用评估结论。     

Gray bootstrap method for estimating frequency-varying random vibration signals with small samples

During environment testing, the estimation of random vibration signals （RVS） is an important technique for the airborne platform safety and reliability. However, the available meth- ods including extreme value envelope method （EVEM）, statistical tolerances method （STM） and improved statistical tolerance method （ISTM） require large samples and typical probability distri- bution. Moreover, the frequency-varying characteristic of RVS is usually not taken into account. Gray bootstrap method （GBM） is proposed to solve the problem of estimating frequency-varying RVS with small samples. Firstly, the estimated indexes are obtained including the estimated inter- val, the estimated uncertainty, the estimated value, the estimated error and estimated reliability. In addition, GBM is applied to estimating the single flight testing of certain aircraft. At last, in order to evaluate the estimated performance, GBM is compared with bootstrap method （BM） and gray method （GM） in testing analysis. The result shows that GBM has superiority for estimating dynamic signals with small samples and estimated reliability is proved to be 100% at the given confidence level.     

Design and experimental study of a micro-groove grinding wheel with spray cooling effect

The effectiveness of grinding fluid supply has a crucial impact on grinding quality and efficiency in high speed grinding. In order to improve the cooling and lubrication, through in-depth research of self-inhaling internal cooling method and intermittent grinding mechanism, a new spray cooling method used in high speed grinding is proposed. By referring to the structure of bowl- shaped dispersion disk, the grinding wheel matrix with atomization ability is designed; through studying heat transfer of droplet collision and the influence of micro-groove on the boiling heat transfer, grinding segment with micro-groove is designed to enhance the heat flux of coolant and achieve maximum heat transfer between droplets and grinding contact zone. High-speed grinding experiments on GH4169 with the developed grinding wheel are carried out. The results show that with the micro-groove grinding wheel just 5.4% of pump outlet flow rate and 0.5% of spindle energy is needed to reduce the grinding temperature to 200℃, which means the developed grinding wheel makes cooling high efficient and low energy consuming.