东山交通隧道爆破振动的安全监测

本文结合宜昌市东山交通隧道掘进时地面建筑物振动测试成果，重点分析了隧道开挖地面振动的特点，并对隧道通过的建筑物进行了安全评估，提出Ⅱ、Ⅲ类围岩隧道开挖地面建筑物振速的安全值。     

《列车引发建筑物振动试验及数值隔振研究》

首先通过现场测试的方法对铁路线附近建筑物的振动特性、建筑物振动的传播规律及其影响因素进行了研究,然后建立了列车 大地 隔振沟 建筑物耦合动力分析模型,对隔振沟的沟深、沟长、沟到建筑物的距离和填充材料等四种结构参数对隔振效果的影响进行了分析。结果表明：列车引发的建筑物振动属于低频振动,建筑物结构对高频振动具有衰减的作用;振动随列车速度的提升而增大,随列车编组的加长而增大,随列车轴重的增加而增大;建筑物的振动水平随楼层的上升呈曲折分布;隔振沟的沟深、沟长、沟与建筑物之间的距离以及填充材料的变化对建筑物楼板的振动都有比较大的影响。     

利用测试建筑物的动力特性分析组合砌体的破坏状态

本文提出了根据建筑物的自振特性判断建筑物破坏状态的方法,并且根据试验结果给出了组合砌体结构在各状态时的振动特性,为以后通过测试这类建筑物的自振特性,判断其破坏状态提供了依据。     

武广高速铁路周边建筑物环境振动特性分析

为了研究高速铁路运营诱发沿线地面以及建筑物二次振动响应特性,通过对武广高速铁路金沙洲路段周边环境与建筑物二次振动进行现场测试与分析,并基于ABAQUS大型非线性有限元分析软件,引入无限元动力分析边界条件,构建列车-轨道-地基-建筑物三维动力有限元模型,对高速铁路环境振动特性进行数值模拟研究,获得了高速铁路周边地面以及邻近建筑物的二次振动响应特性。其研究成果对完善高速铁路环境振动影响评价以及控制方法具有一定的参考价值。     

运行列车对周围建筑物振动影响的试验研究

研究了运行列车对建筑物振动的影响规律。测试时,客车的速度范围为40～115km／h,货车为26～57km／h。测试结果表明：建筑物的振动总的趋势是随与振源距离的增大而减小,随列车车速的提高而增大;相同车速的货车比客车引起的速度振级大5～15dB;对6层建筑物,楼板振动沿层高呈增大趋势,顶层的竖向振级比底层大2～6dB,横向振级比底层大10～15dB;房间中央的楼板振动大于边角和楼梯楼面的振动;楼外地面的速度振级比楼内地面大2～10dB,其差值随振级的增大逐渐变小。列车对附近建筑物的振动影响比较严重,超出了有关标准的规定,应引起重视。     

重载铁路振动对沿线建筑物结构影响试验

选取重载铁路沿线四处有代表性的单层砖混结构建筑物为研究对象,建筑物中心距离铁路分别为6.5 m、15 m、26 m、38 m,其中15 m处的建筑物可作为铁路振动引起建筑物损伤的典型样本。对由列车引发的建筑物基础和屋顶处的振动响应进行现场测试和分析,并将峰值振动速度PPV实测结果与中外相关标准进行对比。结果表明,当峰值振动速度PPV超出GB 50868-2013中的第三类振动限值时,会对我国铁路沿线"建造质量较差的建筑"产生损害。     

无目标计算机视觉技术在斜拉索振动测试中的应用研究

以单台普通消费级相机为测试手段,提出了基于无目标计算机视觉技术的斜拉索振动测试新方法,旨在通过分析斜拉索节段的振动视频来测试其振动特性。基于计算机视觉理论,形成该方法的主要关键点包括：相机参数标定、光流分析和拉索位移的重构。通过刚性塑料管模拟拉索振动实验和某人行桥拉索振动测试,验证了该方法的准确性和适用性。实验结果表明：基于计算机视觉的斜拉索振动测试方法具备了工程振动测试的准确性,且与传统拉索振动测试方法相比,该方法拥有无目标非接触式测量、现场操作便捷、成本低等诸多优点。     

基于Hilbert-Huang变换的爆破振动信号分析

某矿为了保护周围建筑物、提高生产规模,在矿区周边建筑物附近布置了5个测点进行爆破振动测试。对测得的爆破振动信号进行Hilbert-Huang变换分析,得到爆破振动频率>50Hz的占7.56%,10～50Hz的频率占83.34%,<10Hz的频率占9.10%。将爆破振动实测数据进行回归,得到该矿区爆破振动传播规律,从而得到该矿最大段药量与周围砖砌民房的最大许可振动速度有关。结合爆破振动分析和爆破安全规程,把周边建筑物的最大许可振动速度由原来的2.0cm/s提高到2.3cm/s,有效地提高了最大段药量,提升了矿区生产规模,并确保了周边建筑物无损坏。     

基于Hilbert-Huang变换的爆破振动信号分析

某矿为了保护周围建筑物、提高生产规模,在矿区周边建筑物附近布置了5个测点进行爆破振动测试。对测得的爆破振动信号进行Hilbert-Huang变换分析,得到爆破振动频率>50Hz的占7.56%,10～50Hz的频率占83.34%,<10Hz的频率占9.10%。将爆破振动实测数据进行回归,得到该矿区爆破振动传播规律,从而得到该矿最大段药量与周围砖砌民房的最大许可振动速度有关。结合爆破振动分析和爆破安全规程,把周边建筑物的最大许可振动速度由原来的2.0cm/s提高到2.3cm/s,有效地提高了最大段药量,提升了矿区生产规模,并确保了周边建筑物无损坏。     

单面瓦楞机光辊机构动力学分析

单面瓦楞机在成型的过程中存在较大的振动,为了分析振动的原因及减振,对单面瓦楞机的关键机构——光辊机构进行动力学建模,发现推杆刚度不足,造成光辊机构的非线性。进行振动测试,验证了动力学模型的正确性,得到单面瓦楞机振动的主要原因:单面瓦楞机在正常工作转速范围内,存在两个共振频率。最后对光辊机构提出改进方案,并仿真对比改进前后光辊机构在受迫振动下的振动位移,改进后的位移幅值降低了35.2%。研究结果为降低瓦楞机的振动提供了理论依据。     

The Real-Time Mach-Zehnder Interferometer used in Space Experiment

The optical interference method is a promising technique for measuring temperature, density, and concentration in fluids. The non-intrusive and non-invasive nature of its optical techniques to the measured section are its most outstanding features. However, the adverse experiment environment, especially regarding shaking and vibrating, greatly restricts the application of the interferometer. In the present work, an optical diagnostic system consisting of a Mach-Zehnder interferometer (named after physicists Ludwig Mach) and an image processor has been developed that increases the measuring sensitivity compared to conventional experimental methods in fluid mechanics. An image processor has also been developed for obtaining quantitative results by using Fourier transformation. The present facility has been used in observing and measuring the mass transfer process of a water droplet in EAFP protein solution under microgravity condition provided by the satellite Shi Jian No. 8.     

基于拉索静态线形的索力测定

为了充分利用现代测量技术解决索力的精确测定问题,作者基于索段的解析式建立了一种索力测定方法。测得索上三点的相对位置后,就可通过求解非线性方程组得到索力。激光测量仪器可在一个测站对多根索实现快速测量,从而保证了该方法的快速和高效,并且本方法避免了常用的索力测定方法的一个重要不足,即精度受拉索端部条件影响较大。数值算例表明,不考虑索的弹性、由于索的微振动等原因引起的相对位置测量误差等,对索力值的影响都可忽略不计。某斜拉桥工程算例也证明了本方法的微精确性和实用性。本方法可精确测定处于施工过程中和处于使用状态的拉索的索力。     

谐振弦式传感器理论公式修正方法及应用

在简要导出谐振弦式传感器理论公式的基础上，阐述了修正理由，给出了修正公式，实例计算表明，修正公式能显著提高计算精度，最后，利用修正公式对所研制的５０ＭＰａ谐振弦式压力传感器的标定数据进行了处理，给出了相对计算误差。     

Evaluating the soundness of bonding using shearography

Shearography is an optical measurement technique invented to overcome several limitations of holography. One distinct advantage is that it alleviates the stringent environmental stability demanded by holography, rendering the technique practical for industrial applications. There are two modes of shearography, one for measuring surface displacement and the other for measuring surface displacement derivatives. This paper discusses the underlying principle of shearography and its application in nondestructive testing, in particular, of laminated composite structures. In flaw characterization, a thin-plate model is used for back-calculating the shape, size and location of debonds. Shearographic nondestructive testing relies on measuring the response of a defect to stresses. Two practical types of stressing for revelation of debonds are described – static loading using vacuum stressing, and dynamic stressing by means of vibrational excitation. In vibrational stressing, both single frequency excitation and broadband excitation can be used. While vacuum stressing is limited to detecting debonds with closed boundaries, the vibrational excitation can be used for detecting debonds with closed as well as opened boundaries. A major drawback associated with the use of single excitation frequency is the need for vibrating the test object within an appropriate frequency range, as otherwise the test data obtained will not readily reveal the debonds. This paper also describes a new method that uses multiple frequency sweep (equivalent to broadband excitation) which fosters rapid detection and unambiguous assessment of the soundness of adhesive bonding.     

一种谐振式传感器频率特性测试平台

谐振式传感器的谐振频率和Q值可以通过其频率特性计算得到,因此需要有一种通用的测试平台来测量各种不同谐振式传感器的频率特性.本文描述了一种谐振式传感器频率特性测试平台,并提出了一种采用间歇激励方法测试谐振式传感器谐振频率的新方法,采用线性调频信号激励谐振式传感器,传感器自由振动状态下的振动频率即是传感器的谐振频率;测得传感器自由振动状态下的振动频率,即可得到谐振式传感器的谐振频率.     

Photorefractive optical lock-in vibration spectral measurement

An optical photorefractive frequency-domain method is described for measuring displacement amplitude and phase of vibrating surfaces. The method is applicable to diffusely scattering surfaces and usable in either a point-detection or imaging configuration. The method utilizes an optical lock-in approach to measure phase modulation of light scattered from continuously vibrating surfaces. Picometer displacement sensitivities have been demonstrated over a frequency range of 100 Hz to greater than 100 kHz. The response of the spectral method is independent of the vibration frequency above the photorefractive cutoff frequency. Two methods are described that produce a readout beam intensity that is a direct function of the vibration amplitude suitable for imaging.     

Vibration analysis of piezoelectric materials by optical methods

This study provides two noncontact and realtime optical measurement methods to assess the displacement, natural frequencies, and mode shapes of a vibrating piezoelectric material. The methods are carried out using amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) and laser Doppler vibrometer (LDV), which are full-field and point-wise displacement measurement, respectively. Because the fringe patterns measured by AF-ESPI appear as a clear picture at the natural frequency, both natural frequencies and mode shapes of the vibrating material can be successfully obtained. In the LDV system, a swept-sine excitation signal from the function generator to the beam can result in a corresponding peak in frequency response curve at natural frequencies. From the frequency response curve, the natural frequencies are thus acquired. Measured results by both methods are seen to be in good agreement with theoretical predictions by the Galerkin method and finite element method.     

基于成像式照度测量的菲涅尔光学助降系统设计

为了解决菲涅尔光学助降系统的检测问题,提出了一种基于成像式照度探测法的菲涅尔灯发光强度测量方案,并研制了成像式照度探测装置。试验结果表明该装置可远距离对大口径、大发光角度的菲涅尔灯进行发光强度的探测,满足菲涅尔光学助降系统检测装置测量的要求。     

Experimental and numerical investigations for the free vibration of cantilever trapezoidal plates

Abstract

Based on the advantages of non‐contact and full field measurement, the optical technique called amplitude‐fluctuation electronic speckle pattern interferometry (AFESPI) with an out‐of‐plane setup is employed to investigate the free vibration of cantilever trapezoidal plates with various taper ratios and sweep‐back angles. Twenty different plate configurations are analyzed, including triangular and trapezoidal plates, and the first seven vibration modes of each plate are measured. The AF‐ESPI method is very convenient for measuring vibrating objects because no contact is required in contrast to classical modal analysis using accelerometers. Based on the fact that clear fringe patterns will appear only in resonance, both resonant frequencies and corresponding mode shapes can be obtained experimentally using the present technique. Numerical calculations by finite element method are also performed and the results are compared with the experimental measurements. Excellent agreements are obtained for both results of resonant frequencies and mode shapes. The influences of taper ratios and sweep‐back angles on the vibration behavior of cantilever trapezoidal plates are also demonstrated in terms of the dimensionless frequency parameter.     

一种直接驱动式振动管密度测量装置的研制

研制了一种基于直接驱动式振动管原理的密度测量装置。在振动管内为真空和充满无水乙醇的条件下,温度为260～360K、压力为0.1～20MPa范围内标定了装置的仪器常数。通过测量异丙醇和仲丁醇的液体密度检验了装置的性能,并将实验结果与文献数据进行比较,异丙醇数据与文献数据偏差在0.2%以内,仲丁醇数据与文献数据偏差在0.3%以内,验证了装置的精度满足密度测量需求。