高径向支撑性可生物降解聚合物血管支架结构设计与力学性能分析

在研究血管支架支撑单元夹角与其径向支撑强度关系的基础上，提出采用不等高支撑环以利于增大扩张后支撑单元夹角进而提高支架径向支撑强度的设计方法，根据该方法设计了三种可降解聚合物血管支架结构。采用有限元方法对比分析了该三种支架和雅培生物可降解支架(BVS)的径向支撑强度、径向回缩率、轴向短缩率与弯曲刚度，研究了支架结构对这些性能的影响规律。所设计的J型支架(JS)、开放式C型支架(OCS)和密闭式C型支架(CCS)的径向支撑强度相对BVS的径向支撑强度分别提高了14%、34%和42%，同时设计的三种支架的径向回缩率相对BVS的径向回缩率减小了约21%，且均未发生轴向短缩；采用开放式连接形式的JS、OCS的弯曲刚度与BVS的弯曲刚度相当，相比密闭式CCS减小了约73%。影响径向支撑强度和径向回缩率的主要因素是支撑环的结构形式，采用不等高支撑环可有效改善径向支撑强度和径向回缩率；影响轴向短缩率的主要因素是桥筋的结构形式和桥筋的连接位置，采用具有弯曲结构的桥筋且桥筋连接位置位于支撑单元直线段的中间处可避免支架发生轴向短缩；影响弯曲刚度的主要因素是桥筋与支撑环的连接形式，采用开放式连接的支架弯曲刚度更小。     

组合支撑方式下气动多维力多点测量研究

飞行器的设计通常需以其模型在风洞试验中所获取的气动载荷为依据.对于大尺寸、大长径比的飞行器模型,其测试空间受限,常规支撑装置与测量方法难以满足风洞试验的尺寸与动态特性要求.针对上述问题,以压电传感器为核心测试元件,提出了一种结合张线支撑和尾部支撑的组合支撑方式,开发了一种支撑装置与测试元件一体化的气动多维力测试系统.分...     

快速成型中基于单面薄壁的通用支撑设计方法

针对目前快速成型中加支撑技术的缺点，提出了一种全新的支撑设计及实现方法。它基于单面薄壁组件，可组合出任意形状的支撑，并可用统一的轮廓结构表示目前采用的所有支撑形式。在此基础上研究了这种支撑的实时填充实现算法。     

基于气动技术的圆锯片磨削用测量支架的设计

根据圆锯片规格和在线测量系统的工作要求,采用气动技术,设计测量支架的主体支撑结构和尺寸自适应及磨削状态稳定机构。经过实际应用,该系统可实现硬质合金圆锯片的在线测量,可以完全满足磨削在线测量系统的支撑工作要求。     

形状误差测量系统的体系结构

详尽讨论了形状误差测量系统的体系结构 ,包括测量系统的一般构成、形状误差测量的采样逻辑、误差数据的存储结构、采样程序的设备无关性及程序界面等 ,给出了形状误差测量系统的基本框架及构造原则 ,并应用文中给出的基本方法结合笔者从事的圆度、圆柱度、直线度、平面度形状误差的测量和分离研究课题设计出相应的形状误差测量和分离系统。实际应用表明 ,所述的体系结构适宜于各种形状误差的测量系统 ,并易于移植和扩充     

基于四点支撑法的导弹质量质心测量系统设计及误差分析

针对各类截面形状和翼展范围的导弹测量的技术需求,基于四点支撑原理,提出了一种新的导弹质量质心测量方法.在此基础上,进行了测量系统的总体设计。针对测量系统的误差来源,建立了测量系统的误差分析模型。通过分析称重传感器测量误差、系统结构参数及弹体质量对质量、质心测量误差的影响,对系统的结构参数进行了优化,以确保测量系统具有较高的测量精度和可靠性。分析结果表明:对于测量范围内的各种弹体,该测量系统的理论测量精度符合实际精度要求。     

基于激光-CCD的高精度在线测厚系统研究

通过对各种测厚传感器性能指标的综合评价，以及对多种厚度测量方法的对比研究，提出了一种以激光传感器和CCD扫描技术相结合、以计算机控制技术为核心的厚度测量的新方法。实际测量现场中，步进电机突然制动所引入的外来振动干扰以及因环境温度变化所导致的工作台变形都是导致厚度测量误差的重要因素，联合对振动系统的建模分析与对测点位置实时标定，以在线补偿测量误差，由此共同构建一个复合板厚度在线监测系统。实际应用结果表时，该系统可有效抑制外来诸多干扰因素的影响，从而实现了复合板厚度的在线高精度测量。     

变维卡尔曼滤波实现运动目标的跟踪

在球坐标激光跟踪测量系统中，由于受到各种干扰的影响，激光跟踪系统测量所得到的目标状态参量的测量值与目标的真实状态往往不尽相同，如何抑制随机误差，成为提高激光跟踪测量系统精度的一个重要问题。本文提出变维卡尔曼滤波算法来抑制随机误差的影响，仿真结果验证了该方法的有效性。     

管道内表面自动检测仪

介绍一种测量各种管道内表面尺寸和形状的仪器，着重阐述该仪器的组成和工作原理：该仪器采用DSP(Digital signal Processor，数字信号处理器)系统处理图像信号，采用以太网与上位机通信使得测量快速准确，被测管道的长度可达500m。     

测量噪声干扰下的机床主轴系统动态精度分析模型

针对精密机床主轴系统中存在的测量噪声干扰,提出处理该干扰的动态精度模型;为获得高的动态精度,发展了一种由静态测量获得组合特性的方法,并分析了材料本身及传感器的组合特性对动态精度的影响。研究结果表明,当主轴旋转时,组合特性给系统带来的主要是同频及其倍频干扰,这些倍频干扰占有较宽的频带,是影响系统动态特性的主要干扰源。结合实例完成了对材料本身及传感器的组合特性下的动态精度仿真计算,并与实验结果进行对比分析,从中找出影响系统动态精度的主要因素并提出解决办法。     

大攻角旋转天平支撑系统的设计与研究

在对飞机尾旋特性进行分析和预测时,要求获得该飞机的动稳定性导数,这些参数值不能用理论方法计算,必须用风洞试验方法确定。为此,设计了大攻角旋转天平支撑系统,此系统可测定飞机模型在不同姿态角下绕风轴以一系列恒定的角速率旋转时的气动特性。文中简要介绍了研究飞机尾旋的重要性和研究尾旋的方法以及用于低速风洞的大攻角旋转天平支撑系统的总体设计方案、试验能力,该支撑系统角度变化范围大、精度高、风洞的堵塞度小以及支架干扰量小,试验数据的精准度达到了较高的水平,可用于分析、预测飞机的尾旋特性。     

采用平面二次包络环面蜗杆的风洞模型支撑机构设计

风洞是研究航空航天飞行器的基础性关键性地面设备,模型支撑系统是风洞的关键部件,其运动精度和动态特性直接影响风洞试验精度。采用平面二次包络环面蜗杆作为模型支撑系统的传动部件,对模型支撑系统进行有限元分析和优化设计,并将计算结果运用在设计中。模型支撑系统实际运行结果表明,各项设计指标满足使用要求。     

风洞悬臂杆结构主动减振系统的研究

风洞测试时悬臂杆振动会影响测试数据的准确性,为了抑制悬臂杆振动,设计了基于压电驱动器的主动减振系统,提出了将人工神经网络与传统比例积分微分(proportion integration differentiation, 简称PID)相结合的智能控制算法,实现了控制参数在线实时调整。对该控制系统的减振性能分别进行了地面试验和风洞试验,并与采用传统PID控制的试验结果进行对比。结果表明,神经网络PID控制下的振动收敛时间比传统PID缩短了50%,而且在不同风速和攻角下,悬臂杆系统的1阶模态振动均得到了有效衰减（衰减幅度>19 dB）,表现出良好的鲁棒性。     

Model sting support with hard metal core for measurement in the blowdown pressurized wind tunnel

The wind tunnel model, balance and sting are exposed to the large transient load in the blowdown wind tunnels. As part of the research, in order to improve wind tunnel testing, a new high stiffness sting for testing in the T-38 wind tunnel is developed. The existing steel sting, with modular construction, has been used for initial analysis. Its central cylindrical part is changed with core made of material of the high modulus of the elasticity. In this way geometrically the same sting is obtained, but stiffness of the sting is increased. Comparison between elastic characteristics of the combined sting and steel sting is made on the basis of the results obtained by load simulation and experimental verification. Load simulation results are obtained using NX Nastran software. Results of the experimental verification of the new sting are obtained in the T-38 wind tunnel test.     

FL-26风洞模型支撑系统动态仿真分析

研制具有良好力学特性的大迎角模型支撑系统,是解决先进、高机动飞行器大迎角气动力问题的关键技术之一。阐述了FL-26风洞大迎角模型支撑系统结构形式,对系统的动态特性和动力响应进行了有限元分析,获得了大迎角模型支撑系统自由振动时的模态频率和模态振型,以及试验段气动噪声作用下的加速度响应和动应力。仿真结果表明:大迎角模型支撑系统动态特性较好,不同方向的动力响应主频及均方根值分布较为离散且数量级相差较大,未出现共振现象。     

Investigation of wind tunnel wall effect and wing-fuselage interference regarding the prediction of wing aerodynamics and its influence on the horizontal tail

The calculation of aerodynamic characteristics of a wing is the basic problem for aerodynamic design of aircraft. Wing aerodynamics can be determined experimentally and numerically. The method of fixing the wing in the test chamber of wind tunnel is related to disturbance of flow through the wing. When the wing is entirely fixed in the test chamber, the disturbance is usually caused by the sting connecting the wing to the test chamber. The experiments in this paper fixed the wing by clamping to the wind tunnel wall at the wing symmetry surface (root section). With this wing fixation, it was possible to take advantage of the wingspan twice, but to obtain the 3D wing experiment results, it was necessary to evaluate the impact of the wind tunnel wall effect. As for aircrafts, the aerodynamic force of the aircraft’s wing will have certain difference than that of the wing alone. The intersection region between the wind tunnel wall and wing root (for the experiment), as well as between the fuselage and wing root have complex interactions of boundary layers, in particular separation phenomena in the boundary layers. By solving the differential equation for viscous flows, it was possible to visualize the picture of streamlines and flow separations in this interference region and the aerodynamic characteristics of the wing. The singularity method was also used to compare results within its application range. The aerodynamic coefficients in the two cases with and without interference were analyzed. Complex interactions in the interference region could alter the predicted aerodynamic force calculated for the wing alone, which should be estimated. Very strong separations in the wing-fuselage interference region at large angles of attack turned into vortices at the rear impacting on the horizontal tail aerodynamics that is related to the balance problem of the aircraft.

     

Dynamic calibration of magnetic suspension and balance system for sting-free measurement in wind tunnel tests

To avoid flow disturbance generated by mechanical supports around a model and to guarantee flow quality, a magnetic suspension and balance system (MSBS) can be used to measure aerodynamic forces and moments during wind tunnel tests. We present a dynamic method for the efficient multiple degree of freedom calibration of an MSBS. The MSBS has linear characteristics that allow it to be used as a non-contact-type balance. Moreover, the MSBS can measure multi-component external forces at the same time. The calibration results were used to measure the aerodynamic forces and moments acting on a finite wing model over various angles of attack during wind tunnel tests, allowing the aerodynamic coefficients of the finite wing model to be successfully obtained without support interference.     

兆瓦级风力发电机铸造弯头支座的强度分析

弯头支座是机舱内关键部件之一,也是整个直驱风机系统中受力状态最复杂的零部件之一。通过分析风力发电机组在重力、离心力、风压力及其组合作用时机舱弯头支座的承载状态,可以轻松求出最极端的受力。文中使用Samcef进行载荷计算,使用Ansys进行强度分析,系统明确的对风力发电机组弯头支座进行了验证,经过多次验证得出最优结构,取得了良好的效果。     

A new design of a support force measuring system for hypersonic vehicle aerodynamic measurement

In order to simulate the flight state of the aerocraft better, the aerodynamic parameters are obtained by integrating the airframe and propulsion system in a highly integrated configuration and ignition of the engine during the wind tunnel test. At present, the commonly used internal balance scheme forms a system composed of the model, internal balance and the support. However, most hypersonic vehicle models are flat or slender, which makes it difficult to provide installation space for internal balance, improves the difficulty of model design. This note proposes a support force measuring system. By integrating the balance into the structure of the support, it no longer occupies functional space in the cavity of the model, and its special structure can ensure that the additional torque generated by thrust/drag cannot act on the torque measuring element. This study provides a new way of thinking for the integrated model test with propulsion system.