【作者】 张国庆；

【导师】 褚金奎；

【作者基本信息】 大连理工大学 ， 机械制造及其自动化， 2013， 硕士

【摘要】 为了研究鸮类动物飞行消声降噪的机理,本课题组对长耳鸮飞羽多级羽枝的力学性能进行了研究。除羽轴外,飞羽的多级羽枝特征尺寸都在微米量级,属于微尺度力学性能测试的范畴。课题组在总结前人工作的基础上,搭建了一套片外微拉伸测试装置,该测试系统采用压电陶瓷微驱动器驱动,具有纳米级的微位移检测和微牛级的载荷检测单元,并配有图像采集卡对试样安装和测试过程进行实时监测。本文根据长耳鸮飞羽羽枝的测试需要对该测试平台进行设计和改进,主要工作为：基于LabVIEW图形化编程环境编写了测试平台的软件系统,该软件系统主要包括数据实时采集、处理模块,图像实时采集、应用模块。数据采集和图像采集分别利用VISA和ActiveX控件实现了非NI数据采集卡和图像采集卡在LabVIEW中的调用。利用该测试软件可实现拉伸测试实验手动加载或自动加载时实验数据的显示、保存和处理及实验过程的在线监测。基于长耳鸮羽枝固有的粘弹性和拉伸伸长率较大的特点,对测试装置的压电陶瓷微驱动器输出特性进行了改进：首先针对压电陶瓷输出存在迟滞、蠕变及非线性等不良特性编写了PID闭环控制程序对其进行输出控制,控制后使压电陶瓷微驱动器整体输出达到了理想的线性输出,响应速度相比开环时提高了近10倍,满足了飞羽拉伸测试实验均匀加载、快速响应的需求；其次针对压电陶瓷微驱动器输出量程有限的特点,设计了一种基于杠杆原理的两级对称式柔性铰链微位移放大机构,并对机构进行了仿真模拟分析。放大后压电陶瓷微驱动器输出量程达到230μm。基于长耳鸮飞羽羽枝试样形貌不规则难于夹持的特点设计制作了一种机械式微夹具,并对使用该夹具时测试系统的整体刚度进行了标定。最后利用该夹具对长耳鸮飞羽羽枝进行了拉伸测试,得到其杨氏模量为3.13-3.66GPa。应用该夹具测试系统可满足生物毛发等纤维材料的测试需求。更多还原

【Abstract】 In order to research the mechanism of owl class animal flight with little noise, our group has studied on the mechanical properties of Long-cared owl’s fly plume multistage barbs. In addition to the rachis, the feature sizes of multi-level flight feathers barbs are in micron dimension. So the test of barbs is belonging to the category of microscale mechanical testing. On the basis of summing up the work of predecessors, an off-chip micro tensile test device was designed and built. This tensile testing system droved by a piezoelectric ceramics micro-actuator; the displacement and load cell detect resolution with nanoscale and microscale respectively; and equipped with an image acquisition unit to guide sample installation and monitor testing process by real-time. In this paper, according to the needs of long-eared owl flight feathers barbs testing, design and improvement has performed to the testing system. The main job are following:Software system of the test platform was programmed in LabVIEW graphical programming environment, mainly includes data acquisition unit, image capture unit, video capture, image calibration, image application unit and data processing unit. It can achieve calling non-NI data acquisition card and image acquisition card in LabVIEW by use of VISA and ActiveX controls. Using this software could realize data display, save, processing and real-time monitoring during the experiment when tensile test loaded manually or automatically.Based on the inherent viscoelastic characteristic and big tensile elongation of long-eared owl barbs, the output characteristics of the piezoelectric ceramic micro-driver has been improved:Firstly, because of the piezoelectric ceramic’s output has undesirable characteristics of hysteresis, creep and nonlinear. PID closed-loop control program was used to control it. The piezoelectric ceramic micro-driver realize ideal linear output and of the response speed increased nearly10times compared to open-loop after controlled. It meet the uniform load and fast response requirements of the flight feather barbs tensile test. Besides, according to the piezoelectric ceramic micro-driver’s output is limited, a two-level symmetrical flexible hinge micro-displacement amplification mechanism based on the principle of leverage was designed and simulated. The piezoelectric micro-driver output achieved to230μm after amplified. Due to the irregular morphology of owl flight feathers barbs sample, it is difficult to clamp. To solve this problem a mechanical micro fixture was designed. Then the overall stiffness of the test system was calibration when use this fixture, finally, long-eared owl flight feathers barbs’tensile test was carried out by use of the micro fixture and get it’s Young’s modulus was3.13GPa to3.66GPa. The test system could meet the test requirements of the fiber materials like biological hair by use of this fixture.更多还原