时频分析在船载天线和船舶动力系统故障诊断中的应用

针对船载天线传动链和船舶动力系统故障几率高这一问题,构想和简要设计基于IP网和卫星通信技术的远程故障监测诊断系统,分析时域统计量分析、Hilbert包络谱、Hilbert-Huang变换、平移不变多小波相邻系数降噪等振动信号时域和时频域分析工具的基本原理,并将其应用到船载卫通天线传动机构的故障定位诊断中,成功诊断出船载卫通天线传动链振动异常的原因,为船载天线传动链和船舶动力系统的故障监测和定位提供有效的分析方法,为船载装备故障预知维修打下基础。     

基于光纤光栅传感器的复合材料气瓶应变检测

针对复合材料气瓶应变检测的需求,提出了一种光纤光栅传感器植入碳纤维缠绕铝合金内衬的复合材料气瓶的方法,首先在室温下将光纤光栅传感器粘接在经过喷砂处理的铝合金内衬外表面,然后对粘接了光纤光栅传感器的铝合金内衬进行高温老炼,最后进行碳纤维缠绕和固化。开展了8只光纤光栅应变传感器植入复合材料气瓶的试验,其中6只传感器在复合材料气瓶150 ℃/1.5 h固化后保持存活,实现了复合材料气瓶固化、水压疲劳、高温试验等过程中的应变检测。结果表明,所提出的方法可以减小内衬的粗糙外表面导致的光纤光栅信号衰减,验证了光纤光栅传感器植入复合材料气瓶进行应变检测的可行性。     

气流展纤工艺中不同压差和送丝速度对碳纤维展宽的影响

为探究气流展纤工艺中不同出口压差和送丝速度对碳纤维丝束展宽效果的影响,依据Venturi原理,搭建气流展纤试验平台,并记录大丝束碳纤维展宽过程,计算不同工艺参数下碳纤维丝束在不同阶段的展宽率和展宽均匀程度。研究结果表明：通过搭建的气流展纤试验台,能获得展宽率高于400%,展宽均匀程度在90%以上的碳纤维丝束,得到的碳纤维丝束的展宽率与出口压差呈正相关,与送丝速度呈负相关;碳纤维丝束的展宽均匀程度与出口压差呈负相关,与送丝速度呈正相关。     

民用飞机球面框结构设计研究

球面框是民用飞机增压舱的端框,其设计应重点放在以损伤容限安全为基本准则,从球面框的受力分析出发,介绍了一种典型的薄板加筋铆接式球面框结构,以期对球面框的设计起一定的参考和借鉴作用。     

基于二维优化方法的涡轮过渡流道设计

为优化涡轮过渡流道的气动性能,以期提高发动机的整体经济性能,采用二维通流法与单纯性优化算法相结合的方法,对某型发动机涡轮过渡流道进行了二维优化.优化后过渡流道出口的总压损失系数降低了8.4％,流道扩压能力增加了40.4％,同时过渡流道出口气流均匀性也得到很大幅度的改善.使用CFD技术对初始流道和优化后流道性能进行了三维数值模拟,并分析比较了过渡流道与整流支板的三维流场分布,从而验证了二维计算与优化算法的可行性.     

Using a pressure controlled vortex design method to control secondary flow losses in a turbine stage

A turbine design method based on pressure controlled vortex design （PCVD） is presented to design a small-size turbine stage. Contrary to the conventional controlled vortex design （CVD） method, the main objective of PCVD is to control the axial velocity and radial pressure in the sta- tor rotor gap. Through controlling axial velocity, the PCVD establishes a direct tie to meridional stream surface. Thus stream surface variation is induced, resulting in a large secondary flow vortex covering the full blade passage in the respective stator and rotor. This secondary flow vortex could be dedicated to control the secondary flow mitigation and migration. Through radial pressure, the PCVD is also associated with the macroscopic driving force of fluid motion. So the better benefit of CVD can be achieved. The core concept behind PCVD is to mainly control the spanwise pressure gradient by altering profile loading at various spanwise locations. Therefore not only the local pro- file lift is affected, but also the resulting throat widths, stage reaction degree, and massflow rate are altered or redistributed respectively. With the PCVD method, the global stage efficiency is increased successfully while the mass flow rate keeps constant. Additionally there is no endwall shape optimization, stacking optimization, or pitch/chord variations, concentrating solely on varying blade profile deflections and stagger.     

复合材料高压气瓶的碳纤维缠绕设计和ANSYS分析技术

为了获得复合材料气瓶合理的有限元分析模型,并能够有效地掌握气瓶固有的变化规律,以不锈钢316L为内衬、碳纤维(T1000GB)/环氧树脂(BA202)为复合层的高压气瓶作为研究对象,介绍了一种采用螺旋缠绕与环向缠绕组合线型的缠绕设计方法.利用该方法确定复合层厚度、缠绕角、缠绕层数等参数,运用ANSYS程序,采用薄壁壳单元shell91建立了复合层多层结构模型,得出了气瓶应力、应变分布规律,并给出了气瓶疲劳破坏点和起裂点处失效参数的变化历程,最后,将ANSYS计算结果与试验实测结果作了比对分析,为定量化研究复合材料气瓶提供准确的数据支持.研究结果表明:ANSYS数值仿真结果与试验结果吻合良好,采用壳单元shell91可以比较正确地模拟复合层的多层结构;柱形复合材料气瓶破坏薄弱点位于简体(靠封头)部位,气瓶受环向膨胀力影响较大,易使其沿纵向撕裂;随瓶内压力升高,薄壁内衬发生完全塑性变形,复合层仅发生弹性变形.     

复合材料气瓶铝内衬缺陷对疲劳及爆破性能的影响

研究了复合材料气瓶在生产过程中金属内衬存在的凹坑、裂纹以及腐蚀等的缺陷类型,并且对存有以上缺陷类型的复合气瓶进行疲劳及爆破实验,研究其对气瓶的性能影响.结果表明:金属内衬缺陷的存在会使得气瓶在承受内压载荷的过程中,金属内衬在缺陷位置出现应力集中,提前出现裂纹的扩展,使得金属内衬失效,无法充分发挥复合材料层高强度的优势,使得复合材料气瓶的疲劳失效次数及爆破强度大大降低,影响最终的使用性能.     

一种实用高效的压力传感（变送）器校验系统

介绍了一种实用高效的压力传感 (变送 )器校验系统 ,较详细地阐述了这一系统的特点、硬件配置及软件设计方案。     

Flow field and pressure loss analysis of junction and its structure optimization of aircraft hydraulic pipe system

The flow field in junction is complicated due to the ripple property of oil flow velocity and different frequencies of two pumps in aircraft. In this study, the flow fields of T-junction and Y-junction were analyzed using shear stress transport (SST) model in ANSYS/CFX software. The simulation results identified the variation rule of velocity peak in T-junction with different frequencies and phase-differences, meanwhile, the eddy and velocity shock existed in the corner of the T-junction, and the limit working state was obtained. Although the eddy disappeared in Y-junction, the velocity shock and pressure loss were still too big. To address these faults, an arc-junction was designed. Based on the flow fields of arc-junction, the eddy in the junction corner disappeared and the maximum of velocity peak declined compared to T-and Y-junction. Additionally, 8 series of arc-junction with different radiuses were tested to get the variation rule of velocity peak. Through the computation of the pressure loss of three junctions, the arc-junction had a lowest loss value, and its pressure loss reached the minimum value when the curvature radius is 35.42 mm, meanwhile, the velocity shock has decreased in a low phase.