泡沫陶瓷过滤片后添加下置包对提高砂型铸造中铝液充型能力的研究

以铝液的流动性试样为研究对象,研究砂型铸造泡沫陶瓷过滤片后安放一定尺寸的下置包对铝液流动性的影响.同时,将下置包运用于生产热裂圆环薄壁铸件,表明:在泡沫陶瓷过滤片后安放一定尺寸的下置包对金属液的充型能力有较大提高,并且下置包的设置和安放工艺简单.     

K2ZrF6助浸SiC涂层碳纤维增强Al复合材料的研究

研究了用K_2ZrF_6助浸法制造C/Al复合材料的工艺和K_2ZrF_6的助浸机理结果表明:K_2ZrF_6处理后,C,Al间的润湿性仍比SiC,Al间的差C,Al间的润湿主要靠大量的界面化学反应、这使得复合材料的制造十分困难;而SiC、Al间的润湿靠微量的SiC在Al中的溶解K在纤维或涂层中的扩散也可能起助浸作用Al液在极短时间内对SiC涂层后的纤维束或纤维预制件浸渍良好同时,将基体Si合金化后,获得了完整的CF/SiC/Al界面,圆满解决了C/Al复合材料的界面相容性和制造中的问题     

溪洛渡水电站掺PVA纤维混凝土的试验研究及应用

溪洛渡水电站拦河大坝为双曲拱坝,最大坝高285．5m,大坝混凝土抗裂指标要求高,为了提高混凝土的极限拉伸值、自生体积变形性能,进行外掺改性PVA纤维大坝混凝土配合比的试验研究,并在溪洛渡水电站工程成功应用。室内试验研究和对大坝混凝土的抽样检测结果表明,掺改性PVA纤维混凝土可提高28d龄期混凝土极限拉伸值10％以上,相同龄期可减少混凝土自生体积变形收缩约15×10^-6左右,有效的提高了大坝混凝土的抗裂性能指标。     

基于SoC_FC芯片的电源管理系统设计与实现

机载智能电源管理系统作为航空电子系统的心脏,其功能和性能直接影响着整个航电系统的运行,因此电源管理系统的设计至关重要。介绍了一种以自主研发的高性能、高可靠性、高集成度的光纤通道芯片SoC_FC为主控制器的电源管理系统的软硬件设计与实现过程。硬件平台以SoC_FC为核心,外扩A/D转换、存储器等电路,软件设计以嵌入式操作系统VxWorks为平台。通过引入光纤通道芯片SoC_FC不仅满足了电源管理系统功能及性能的需求,同时有效地缩短了研发周期,满足了飞机高度综合、小型化的发展需求。     

Nano-Engineered Carbon Fibre-Based Piezoelectric Smart Composites for Energy Harvesting and Self-Powered Sensing

The integration of piezoelectric materials onto carbon fiber (CF) can add energy harvesting and self-power sensing capabilities enabling great potential for “Internet of Things” (IoT) applications in motion tracking, environmental sensing, and personal portable electronics. Herein, a CF-based smart composite is developed by integrating piezoelectric poly(3,4-ethylenedioxythiophene) (PEDOT)/CuSCN-coated ZnO nanorods onto the CF surfaces with no detrimental effect on the mechanical properties of the composite, forming composites using two different polymer matrices: highly flexible polydimethylsiloxane (PDMS) and more rigid epoxy. The PDMS-coated piezoelectric smart composite can serve as an energy harvester and a self-powered sensor for detecting variations in impact acceleration with increasing output voltage from 1.4 to 7.6 V under impact acceleration from 0.1 to 0.4 m s⁻². Using epoxy as the matrix for a CF-reinforced plastic (CFRP) device with sensing and detection functions produces a voltage varying from 0.27 to 3.53 V when impacted at acceleration from 0.1 to 0.4 m s⁻², with a lower output compared to the PDMS-coated device attributed to the greater stiffness of the matrix. Finally, spatially sensitive detection is demonstrated by positioning two piezoelectric structures at different locations, which can identify the location as well as the level of the impacting force from the fabricated device.     

Fatigue behaviour and modelling of talc‐filled and short glass fibre reinforced thermoplastics,including temperature and mean stress effects

Effects of temperature and mean stress on fatigue behaviour of talc‐filled polypropylene (PP‐T) and short glass fibre reinforced polypropylene (PP‐G), polyamide‐66 (PA66), and a blend of polyphenylene ether and polystyrene (PPE/PS) were investigated. Load‐controlled fatigue tests were conducted under positive stress ratios (R = 0.1 and 0.3) and at several temperatures (T = 23, 85 and 120 °C). Larson–Miller parameter was used and a shift factor of Arrhenius type was developed to correlate fatigue data at various temperatures. Effect of mean stress on fatigue life was significant for some of the studied materials; however, for the PPE/PS blend no effect of mean stress was observed. Modified Goodman and Walker mean stress equations were evaluated for their ability to correlate mean stress data. A general fatigue life prediction model was also used to account for the effects of mean stress, temperature, anisotropy and frequency.     

碳纤复合约束阻尼结构共固化成型及其性能研究

使用共固化成型工艺制备了含碳纤复合材料约束层的轻质约束阻尼结构,采用180°剥离强度测试、振动性能测试对结构界面结合强度、减振性能进行测试,并通过扫描电镜观测试样内部界面微观形貌。结果表明,所制备碳纤复合约束阻尼结构中约束层与阻尼层界面结合紧密,剥离强度接近5 k N/m,减振量超过19d B,结构减重50%以上,具备较高的应用价值。     

Effect of nozzle type on pulse-jet cleaning performance of ceramic filter tube

The dust-cleaning efficiency of the ceramic filter tube is the key factor to determine the long-term stable operation of the dust removal system, and the type of nozzle significantly influences the performance. In this study, four types of nozzles (injection hole, sudden enlargement nozzle, tubular nozzle, and induction nozzle) are used to conduct comparative experimental study on the dust-cleaning effect of the ceramic filter tube. Using the schlieren technique find that the tubular and induction nozzles can improve the deviation angle of pulse-jet airflow. The injection parameters were set as an injection pressure of 200 kPa, an injection distance of 120 mm and a pulse width of 80 ms in the experiment. Using the sidewall pressure measurement system indicates that the integrated pressure of the sudden enlargement nozzle is the largest, but the uniformity is poor. The comprehensive pressure of the sudden enlargement nozzle is increased by 64.86 %, and the non-uniformity is reduced by 28.62 % compared with those of the induction nozzle. Using the visualization filtration cycle test system implies that the degree of damage and stripping state of the dust layer are directly proportional to the sidewall pressure. Moreover, it is found that the residual pressure drop changes exponentially with the dust removal quality under different nozzle types. These conclusions can help explain the mechanism of dust stripping and provide a basis for the selection of nozzles.     

连续纤维增强热塑性复合材料的制备成型技术及其应用前景

介绍了连续纤维增强热塑性复合材料（ＣＦＲＴＰ）的材料组成,综述了ＣＦＲＴＰ的主要制备技术、成型方法以及应用前景。     

陶瓷刀具模糊可靠性及其与刀具材料力学性能的关系

基于模糊数学和可靠性数学的基本理论 ,阐述了刀具模糊可靠性的基本概念和评价方法 ,并进一步应用于陶瓷刀具研究领域 ,建立了陶瓷刀具模糊可靠性与刀具材料力学性能的关系 ,从而使得不做或少做切削实验就能评价陶瓷刀具可靠性的设想成为可能