压电动态拉应力传感器研究

该文提出一种用于混凝土结构内部动态拉应力测量的嵌入式应力传感器,在介绍其基本工作原理和结构的基础上,设计制作了拉应力传感器灵敏度标定装置,对一组传感器试样进行动态拉应力测量灵敏度标定。研究了压电陶瓷预加压应力下传感器输出电压与拉应力水平的线性关系,并比较了在不同预紧力水平下传感器的灵敏度。试验结果表明,制作的传感器输出电压与动态拉应力线性相关度较好,预紧力的施加可进一步提高线性相关度,且所制作的不同传感器间的灵敏度差异小。     

浮动式剪应力微传感器的标定

流体壁面剪应力微传感器的精确标定是进行流动测量的基础。分别采用自重加载、离心加载和风洞吹风三种不同方法,对基于电容检测原理的浮动单元剪应力微传感器进行标定与实验研究。对比了三种实验方法和标定的结果,分析了标定过程中的设备、传感器的加工及安装等误差的影响。研究结果表明,标定的传感器灵敏度为30 mV/Pa,三种标定方法的误差在2%以内,采用离心加载标定的误差最小;为进一步减小标定误差提供了改进方法。利用标定后的传感器,在风洞中对标准翼型的定点壁面剪应力值进行了测量,与仿真结果进行对比,二者能够较好吻合。     

圆筒谐振式压力传感器

由于压力不同,薄壁圆筒的固有振动频率也不同。利用这一原理,研制了圆筒谐振式压力传感器。下面就其工作原理、性能以及特点作一概述。 近年来,随着计算机的飞速发展,计算机与传感器的接口已成为一个重要问题,因此,人们广泛报导了高精度的A/D变换器。由于圆筒式压力传感器为频率输出式,所以用简单的数字电路容易实现约24bit的变换,     

光纤光栅液体双参量传感器增敏设计

为了解决现有光纤布喇格光栅(FBG)传感器温度与压力灵敏度低的问题,设计了一种基于FBG的薄壁圆筒式液体温度与压力传感器.选用具有耐腐蚀、弹性性能好以及热膨胀系数大的不锈钢304和铍青铜C17200分别对传感器进行封装,采用有限元分析法对传感器进行压力和温度特性仿真分析,研究了敏感元件材料及尺寸大小对灵敏度的影响,并分...     

光纤光栅温度压力同时区分测量技术研究

提出一种基于金属合金薄壁弹性圆筒双光纤Bragg光栅(FBG)温度压力同时区分测量的传感模型。将FBG1和FBG2分别沿着圆筒的轴线方向粘贴在空心段外壁上和底座实心的外壁面上。圆筒内压力和温度的变化将引起FBG1波长的变化,温度的变化引起FBG2波长的变化,通过FBG2对FBG1的温度补偿进行温度和压力的同时区分测量。在100℃内2、0 MPa压力下,实验测得传感器的压力响应灵敏度系数约为0.012 nm/MPa,温度响应灵敏度系数约为0.012 nm/℃。     

表面式FBG应变传感器及其在高速公路桥梁工程中的应用

报道一种表面安装式光纤布喇格光栅(FBG)应变传感器及其在高速公路高架桥的车辆载荷压力试验中的应用。提出了一种具备应变放大能力且可调节的不锈钢封装的应变感测弹性结构,布设有FBG的弹性圆筒结构位于传感器中间部分,其横截面积小于传感器其他部分,传感器的应变测量放大系数可通过改变圆筒结构的长度和横截面积来调节。将24个经过测试标定后的应变传感器和6个FBG温度补偿传感器安装在甬台温高速吊水沿大桥箱梁底部,并对大桥实施一系列车辆载荷作用下的静态和动态试验,传感器表现出了良好的测量能力,3种静态载荷工况下的桥梁底部应变大小以及3种动态载荷工况下的应变变化情况被清晰地展现出来,理论分析与实验结果一致。     

布里渊温度和压力传感器增敏设计

设计了一种基于分布式传感技术的薄壁圆筒型液体温度和压力传感器.选取具有耐腐蚀、弹性性能好以及热膨胀系数大的不锈钢316L和铍青铜C17200分别对传感器进行封装.利用有限元仿真软件ANSYS Workbench对封装的传感器压力和温度特性进行仿真分析,得到器件的径向应变量,分析其布里渊频移随压力和温度的变化关系.仿真实验表明,使用铍青铜C17200封装的传感器压力灵敏度和温度灵敏度更高,在0～12 MPa、-5～40℃范围内压力灵敏度达11.1 MHz/MPa,温度灵敏度达2.56 MHz/℃,相较于普通单模光纤分别提升7.4倍和1.7倍.     

光纤光栅和静态电阻在静压模型管桩测试中的对比试验研究

为了提高光纤布拉格光栅(fiber Bragg gratin g,简称FBG)应变传感器测量精度,针对光纤光栅传 感器在模型管桩试验应用情况,提出了一种光纤光栅传感器理论灵敏度系数和实验灵敏度系 数应变标定方 法。该方法通过实验标定微型光纤光栅应变传感器的灵敏度系数,与理论分析传感器灵敏度 系数进行对比, 同时在模型管桩安装传感器位置粘贴应变片。实验结果表明,标定后的FBG应变传感器测试 结果更加准确, 为基于FBG应变传感器的模型管桩监测技术奠定了基础。同时,该方法适用于FBG传感器应 用与模型管 桩前的标定,可以得到准确反映模型管桩受力变形的真实数据,提高了光纤光栅传感器在模 型管桩试验中 的测量精度。同时,该方法简单、易操作,为光纤光栅传感器在试验和工程中应用奠定了基 础,加快了FBG 传感器在模型管桩荷载传递监测应用的步伐。     

光纤FBG高压传感器的优化设计与实验研究

基于对FBG传感器薄壁圆筒材料和结构的优化设计,制作了FBG高压传感器,在0～50MPa压力范围,进行了加压和减压高压实验,实验结果表明:FBG的压力灵敏度为0.0374nm/MPa,其中心波长与压力变化有着良好的线性关系和重复性,且迟滞性好。模拟结果与实验结果很好吻合。     

基于光纤光栅的双壁开口模型管桩测试技术研究

针对光纤光栅传感器在模型管 桩试验应用情况, 提出了一种光纤光栅传感器理论灵敏度系数和实验灵敏度系数应变标定方法。结合理论分析 ,在封装FBG 应变传感器前,对模型管桩内、外管进行有限元Abaqus应力分布模拟分析,得到双壁开口模 型管桩对封装 FBG应变传感器没有影响,提高了实验应变测量精度。对模型管桩封装后的FBG应变传感器进 行标定实验, 每次按200逐级加载后并卸载,循环加载5次,得到内外管FBG传感器 应变灵敏度系数分别为2.15 pm/με、2.24 p m/με,且线性度 均达到0.999以上。该方法简单、易操作,可用于光纤光栅应变传感 器在模型管桩试验前的标定,为光纤光栅传感器在试验和工程中应用奠定了基础。     

表面应力测量SOI压阻悬臂梁传感器设计与优化

研究了基于SOI(silicon on insulator)工艺的压阻悬臂梁传感器的静态和动态特性,推导了其用于表面应力测量时灵敏度和分辨率的表达式.分析了各种参数对性能的影响,提出了参数设计与优化的流程.得到了一套灵敏度为-1.8×10-3m/N,分辨率为8.5×10-5N/m,弹性系数为0.023N/m,谐振频率为1.3×104Hz的设计参数.     

Expanding the Horizon of Mechanochromic Detection by Luminescent Shear Stress Sensor Supraparticles

Novel sensor particles have been developed that expand the variety of today's mechanochromic systems. The developed supraparticles consist of several different components to enable the sensor function. First, a luminescence‐quenching core material is coated with silica nanoparticles. Second, this structure is surrounded by raspberry‐like nanostructured silica particles, which host luminophore moieties. Upon shear stress, components spatially separated in the original supraparticles, namely quencher and luminophore components, come into contact. This causes an irreversible quenching of the luminescence (sensor turn‐off). Different options to select core, quencher, and luminophore components allow to drive the sensors to different sensing options regarding response time, sensitivity, and operation time. The sensors can be sensitive and rapid in response or generated to monitor the influence of shear stress over longer periods of time. Thus, a rapid, visible, “on‐the‐fly” sensing of shear stress is possible as well as monitoring the impact of prolonged shear stress. The particles are assembled by spray‐drying. This affords flexibility when choosing the type of quencher and luminophore moiety. As such, the sensitivity of this robust, particle‐based shear stress sensor system can be deliberately configured. Furthermore, the supraparticle sensor can be integrated in surfaces to create interactive, communicating materials.     

Stress-transfer characteristics of embedded fiber Bragg grating sensors

There is an increasing demand for providing on-linehealth monitoring of concrete structures in order to de-tect the structural performance deteriorationearly.FiberBragg grating (FBG) sensors ,thanks to their intrinsiclongtermstabilityfeatures suchasinherenti mmunitytoEMI ,small size and various multiplexingcapability,be-come the opti mal sensors used in health monitoring ofconcrete structures[1].However ,there are still a lot ofproblems for FBGsensors to be resolved whenit is ap-plied in h…     

Shear Strain Influence on Fiber Bragg Grating Measurement Systems

Fiber Bragg grating (FBG) sensors have become commercially available sensors for the measurement of temperature, strain, and many other quantities. One interesting application is the embedding of these sensors, during which shear strains can arise inside the sensor. As we have recently demonstrated by a full-tensor coupled-mode analysis, shear strains do influence the spectral response of fiber Bragg sensors, and thus have to be considered. In this paper, we use the theory behind this analysis to compute the direct influence of shear strains on the output of a FBG measurement system, and show cases where shear strain effects are relevant. Furthermore, we compare the sensitivity of different interrogation algorithms toward shear strain influences on the measurement system output. To model the experimentally relevant unpolarized light sources, we derive a model using the monochromatic waves of coupled-mode theory. We apply the unpolarized light to the FBG shear strain problem and show that for unpolarized light, shear strain has to be taken into account as well. We find absolute measurement errors in the range of 100 pm. For typical normal strain measurements, this would be of an order of 10% of relative error.     

Thermo-mechanical characterization of passive stress sensors in Si interposer

Thermo-mechanical stress is a major concern in the frame of 2.5D integration. Passive stress sensors were integrated in a silicon interposer test vehicle to quantify stress at critical locations. The sensors were integrated in a rosette-shape consisting of eight oriented copper serpentines acting like strain gauges. This innovative design allows the calculation of a partial stress tensor, including three planar and one out-of-plane components. Electrical measurements at wafer level, combined with FIB/SEM cross-sections, revealed a strong impact of elaboration processes on the structures electrical characteristics. Numerical simulations using finite element analysis were built to evaluate the sensitivity of copper serpentines to mechanical stress. Finally a dedicated four-point bending tool coupled with a four-terminal resistance measurement setup was fabricated to experimentally extract the values of sensors sensitivity factors. Preliminary results depicted in this paper highlight a sensitivity to stress of distinctly oriented resistors. Several identified sources of data dispersion are inherent to the present measurement configuration. Added-value and limitations of such sensors were underlined, and recommendations regarding the testing strategy were drawn to allow a reliable estimation of the stress fields.     

基于压电材料的钢筋砼-钢组合塔筒损伤监测

钢筋混凝土-钢组合塔筒作为一种新型的风电塔架形式,其混凝土段的开裂对其使用寿命具有重要影响,对其混凝土段的开裂进行监测具有重要意义。该文提出了一种基于压电陶瓷激励的应力波测量的钢筋混凝土塔段的开裂监测方法,以某钢筋混凝土-钢塔筒缩尺模型为对象,以布置在钢筋混凝土塔筒表面的压电陶瓷片为激励器,利用布置在钢筋混凝土塔筒不同高度位置的压电陶瓷片作为传感器,实现在不同水平往复加载下的应力波的测量。对混凝土塔段从裂缝开始出现直至构件最终破坏整个过程各压电陶瓷片的响应进行分析,并定义损伤指标。结果表明,定义的指标不仅可较好反应裂缝实际出现位置,且与加载等级相关,所提出的监测方法可对钢筋混凝土塔段裂缝的发生和发展过程进行有效监测。     

Effect of mechanically induced ionization processes in polymer insulators on the noise of cable sensors of physical fields

The noise of cable antennas that is induced by electrization of polymer elements due to mechanical stress is considered. An assumption on an important role of the ionization processes in the generation of electric fields in deformable polymer materials of sensors (antennas) that are used for the measurement of electric and acoustic fields is substantiated. It is demonstrated that the formation of electret that causes variations in the sensitivity of sensors with respect to external mechanical action is possible owing to deformation of the cable insulation. The electrophysical processes in polymer insulators induced by mechanical stress must be taken into account in the development of methods for an increase in the real sensitivity of the measurement devices.     

基于嵌入压电技术的钢管核心混凝土缺陷检测

钢管混凝土构件核心混凝土缺陷影响到其延性和承载力。利用自制的嵌入式压电功能元,该文提出了基于压电陶瓷应力波测量与分析的核心混凝土缺陷监测方法。通过对比在不同状态的简谐激励下测量信号幅值和扫频激励下小波包能量的差异,定义了基于测量信号幅值和小波包能量的损伤指标。结果表明,利用提出的嵌入式压电技术和定义的损伤指标,有效地识别了钢管混凝土构件的核心混凝土损伤,损伤指标对损伤程度敏感。