用巨磁电阻式位置传感器测量材料的杨氏模量

介绍了一种新型高灵敏度巨磁电阻式传感器的工作原理和使用方法,并利用它测量了钢片的杨氏模量。实验结果表明：用该巨磁电阻式传感器测量杨氏模量,测量方法实用性强,精确度较高。     

PSD位置传感器在杨氏弹性模量测量中的应用

介绍了PSD位置传感器的检测原理和一种基于PSD的钢丝杨氏弹性模量测量系统.实验结果表明,利用该系统可精确地测得杨氏模量,并且能定性地分析出钢丝在恒定外力(砝码)作用下的变化过程.     

PSD位置传感器在杨氏弹性模量测量中有应用

介绍了PSD位置传感器的检测原理和一种基于PSD的钢丝杨氏弹性模量测量系统。实验结果表明，利用该系统可精确地测得杨氏模量，并且能定性地分析出钢丝在恒定外力(砝码)作用下的变化过程。     

基于弹性体碰撞时间测定的杨氏模量测量

杨氏弹性模量是反映材料形变与内应力关系的物理量,是工程技术中的常用参数.介绍了一种金属平板杨氏模量测量的方法.该方法运用弹性力学的相关理论,即弹性体碰撞时间与金属平板杨氏模量的关系;使用微处理器技术,通过测量金属小球与金属平板的碰撞时间测定法,实现测量该金属平板的杨氏模量.测量结果表明,用该方法测量得到的铝板、不锈钢板和A3钢板的杨氏模量与理论数据误差在±5%以内.     

PSD的光电响应特征及其在杨氏模量测量中的应用

针对目前大学教学中较为广泛应用的材料杨氏弹性模量测量方法和测量结果准确性方面存在的问题,对位置敏感探测器(PSD)的光电响应特性进行了系统的分析与研究,并利用此响应特征,基于杨氏弹性模量静态测量方法与原理,设计了两次复式光放大的新型传感方式,应用PSD作为微量位移测量的传感器,在小空间内实现了微测量放大的作用,使杨氏弹性模量测量结果的精度提高了1个数量级。     

光子晶体压力传感器研究

介绍了一种新型光子晶体压力传感器,利用压力使光子晶体带隙的变化特性制作压力传感器,提出了通过测量透射光的变化来测量压力的检测方法。结果表明:传感器的测量范围和灵敏度与构成光子晶体的材料特性有关,材料弹性模量小时,灵敏度高;2种材料的弹性模量和泊松比相差大时,测量范围小。该传感器体积小、重量轻。     

基于超声迟到回波的固体弹性模量测量

由于航空工业的特殊性,对于一些外部供应商提供的飞机零部件,其具体的力学性能无法获取,这就对其地面和飞行试验中的应变和载荷监测结果的准确性校准造成困难。针对未知材料特性固体结构弹性模量的测量需求,本文提出了一种基于超声检测时迟到回波形成原理的测量方法,利用常用的超声纵波直探头对材料横波声速进行测量,并根据弹性模量、泊松比、密度、纵波声速和横波声速之间的固有关系,计算得出材料的弹性模量。该方法不需要额外制造试块,不需要使用横波探头和复杂的试验设备,是一种测量未知材料特性固体结构弹性模量的通用方法。通过实验验证,该方法可较准确地测量弹性模量。     

基于声测量原理的多用途空间目标定位方法研究

多种类的目标定位使用实时声测量方法与现有电子雷达或光学测量方法相比,具有反电子干扰、反低空突防、隐蔽性好、响应时间快及设备简单等优点。针对现有声测量方法所采用的平面或立体声传感器阵的测量精度低和测量系统应用单一的问题,提出了基于六面锥体声传感器阵的测量方法,推导了该阵列的基本定位算法和模型,进行了测量系统不确定度分析和构建,经实验证明测试系统测量误差不大于±5%。以六面锥体声传感器阵为主所构成的测量系统,可用于对空射击弹目/炸目偏差、地面侦查炮位及防空预警。     

基于螺管形差动变压器的非接触式扭矩传感器的研究

扭矩测量是传动线路中的重要内容之一,高精度、高稳定性的非接触式扭矩测量方法是当今各国机械量测量研究的热点之一,为此,提出了一种基于螺管形差动变压器的非接触式扭矩传感器的研究.系统介绍了该测量方法的原理与结构.经实验证实:该测量原理可行,所设计的扭矩传感器具有较好的线性度和一致性,重复精度0.5%.     

最小跳数路由无线传感器网络中的节点距离测量

无线传感器网络中的间接距离测量是一种性价比极高的距离测量方法,但目前测量精度还有待进一步提高。根据最小跳数路由无线传感器网络的行为特征,提出了一种基于最小跳数路由及其路由重复数的节点距离测量算法,与DV-hop算法相比,借助路由重复数较大地提高了距离测量精度。理论分析及仿真结果表明,该算法在节点密集分布的无线传感器网络中具有很好的效果。     

扫频法测量混凝土动弹特性

扫频法的最大特点是不仅能够读取李萨如的数据,还能根据扫频的极值判断试件的峰值频率、动弹特性数据,同时根据频率峰值的数量和幅度分析试件可能存在裂缝等的缺欠.扫频法是当前测量混凝土、金属、炭素等物体的新方法.     

MEMS器件贴片工艺研究

贴片工艺是MEMS封装中的关键工艺。根据残余应力理论,应用有限元方法和试验技术研究了贴片胶杨氏模量和热膨胀系数对贴片应力和芯片翘曲的影响。结果表明:杨氏模量和热膨胀系数是影响贴片应力和芯片翘曲的重要因数。杨氏模量越大,贴片后产生的应力越大,引起芯片的翘曲越大,但杨氏模量大到一定数值后,应力不会再增大,反而对应力具有一定的隔离作用;热膨胀系数越大,贴片后产生的应力越小,引起芯片的翘曲越小,反之,引起芯片的翘曲越大。在满足粘接强度和工艺条件下,选用软胶有利于减小应力和芯片翘曲。     

A new technique for measuring the mechanical properties of thinfilms

Accurate measurement of mechanical properties is very difficult for films that are only a few microns thick. Previously, these properties have been determined by indirect methods such as cantilever beam and diaphragm bulge tests. This paper presents a new technique to measure the Young's modulus of thin films in a direct manner consistent with its definition. Strain is measured by a laser-based technique that enables direct and accurate recording of strain on a thin-film specimen. Load is recorded with a 1-lb load cell, and an air bearing is used to eliminate friction in the loading system. The specimen is phosphorus-doped polysilicon that has a gage cross section of 3.5 μm thick by 600 μm wide. All 29 uniaxial tensile tests show brittle behavior, and the average values of Young's modulus and fracture strength are measured to be 170±6.7 GPa and 1.21±0.16 GPa, respectively. One fatigue test is also reported in this paper     

高g_n值MEMS加速度传感器封装的研究

对一种新型双悬臂梁高gn 值MEMS加速度传感器进行有限元模拟。采用双悬臂梁传感芯片的一种实际封装结构 ,进行频域分析和时域分析 ,讨论封合传感器芯片和封装基体的封合材料对其输出信号的影响。频域分析表明 ,封合材料的杨氏模量对封装后加速度传感器整体的振动模态有一定影响 ,封合胶的杨氏模量很小时 ,会致使加速度传感器的信号失真 ,模拟表明可选用杨氏模量足够高的环氧树脂类作高gn 值传感器的封合材料。时域分析静态模拟表明 ,封合材料的杨氏模量 ,对最大等效应力和沿加载垂直方向的正应力最大最小值基本无影响。时域分析动态模拟表明 ,随着封合材料杨氏模量的提高 ,动态模拟输出的悬臂梁末端节点位移的波形和其经数字滤波后输出的信号变好 ,封合材料的杨氏模量不影响输出信号的频率和均值 ,在加速度脉冲幅值输入信号变化时 ,悬臂梁末端位移平均值输出信号与输入有良好的线性关系。     

Process Temperature–Dependent Mechanical Properties of Polysilicon Measured Using a Novel Tensile Test Structure

A new test structure was developed to measure three major unknown mechanical parameters of deposited thin films, i.e., fracture strength, Young's modulus, and residual stress. The structure was designed to have plural specimens of a deposited thin film bridging the gap of the silicon substrate and enables the easy and efficient tensile testing of the film. It was used to measure those parameters of various polysilicon films. Polysilicon is commonly used as a structural material of microelectromechanical systems (MEMS) after being deposited at a temperature below 600 degC and annealed at a temperature around 1000 degC to remove the residual stress. On the other hand, polysilicon can be also deposited at a temperature higher than 600 degC. The three parameters of polysilicon films depend on process temperature and were evaluated using the new test structure. Concerning the strength, films deposited at 560 degC had the highest strength when annealed at 850 degC. Films deposited at 625 degC and annealed at 1050 degC were weaker than those deposited at 560 degC and annealed at 1050 degC. Young's modulus was found to behave in a similar way. The trend of the residual stress was the same as already reported, but its local evaluation was possible in combination with the tensile strength determination     

锚固边坡岩体流变力学数值分析

利用MSC Marc软件建立锚固边坡的整体模型,考察岩体的流变特性和锚杆的弹性模量对锚固边坡的影响,全面分析在不同流变系数的岩体和不同弹性模量锚杆的情况下边坡的变形、岩体的流变以及锚杆的应力松弛情况,为进一步改善锚固边坡的设计提供数值分析参考.     

应用于激光超声检测的新型光偏转探测技术

针对现有激光超声薄膜杨氏模量测量方法,提出了一种新型的光束微偏转探测技术.该技术采用差分检测方法抑制了系统共模噪声;采用共焦结构增强了检测系统稳定性、减弱了环境扰动的影响.并阐述了此探测技术的工作原理.将其应用于激光超声薄膜杨氏模量测量系统,获得了声表面波在标准样品中的传播色散曲线.实验色散曲线与理论计算值的良好拟和验...     

Estimation of elastic constant of rocks using an ANFIS approach

The engineering properties of the rocks have the most vital role in planning of rock excavation and construction for optimum utilization of earth resources with greater safety and least damage to surroundings. The design and construction of structure is influenced by physico-mechanical properties of rock mass. Young's modulus provides insight about the magnitude and characteristic of the rock mass deformation due to change in stress field. The determination of the Young's modulus in laboratory is very time consuming and costly. Therefore, basic rock properties like point load, density and water absorption have been used to predict the Young's modulus. Point load, density and water absorption can be easily determined in field as well as laboratory and are pertinent properties to characterize a rock mass. The artificial neural network (ANN), fuzzy inference system (FIS) and neuro fuzzy are promising techniques which have proven to be very reliable in recent years. In, present study, neuro fuzzy system is applied to predict the rock Young's modulus to overcome the limitation of ANN and fuzzy logic. Total 85 dataset were used for training the network and 10 dataset for testing and validation of network rules. The network performance indices correlation coefficient, mean absolute percentage error (MAPE), root mean square error (RMSE), and variance account for (VAF) are found to be 0.6643, 7.583, 6.799, and 91.95 respectively, which endow with high performance of predictive neuro-fuzzy system to make use for prediction of complex rock parameter.     

Mechanical property characterization of LPCVD silicon nitride thin films at cryogenic temperatures

T-shape, LPCVD silicon nitride cantilevers are fabricated to determine Young's modulus and fracture strength of silicon nitride thin films at room and cryogenic temperatures. A helium-cooled measurement setup is developed and installed inside a focused-ion-beam (FIB) system. A lead-zirconate-titanate (PZT) translator powered by a function generator and a dc voltage is utilized as an actuator, and a silicon diode is used as a temperature sensor in this setup. Resonant frequencies of identical cantilevers with different "milling masses" are measured to obtain thickness and Young's modulus of the silicon nitride thin films, while a bending test is performed to obtain fracture strength. From the experiment, the average Young's modulus of low-pressure chemical-vapor deposition (LPCVD) silicon nitride thin films varies from 260.5 GPa at room temperature (298 K) to 266.6 GPa at 30 K, and the average fracture strength ranges from 6.9 GPa at room temperature to 7.9 GPa at 30 K. The measurement setup and technique presented here can be used to characterize the mechanical properties of different MEMS materials at cryogenic temperatures.