共查询到20条相似文献，搜索用时 218 毫秒
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微型高精度多点位移计的设计及在三维模型实验中的应用 总被引：9，自引：1，他引：9
岩体力学模型试验是研究复杂岩体内部建筑物稳定及破坏的一种重要方法。在各种地质，边界和荷载条件下，地下洞室群周围岩体的应力，变形以及破坏机理等十分复杂。超大型水电站地下厂房洞室群以其规模巨大，洞室结构形式多样，围岩稳定问题复杂而备受关注，但是许多制约因素使得这类试验难以实现，其中包括试验过程中内部物理量的量测问题，本文就为解决模型试验中的位移量测问题而进行的微型高精度多点位移计设计，埋设和安装等有关问题进行了探索，并介绍了它在溪洛渡水电站地下厂房洞室群模型试验中的成功应用。 相似文献
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康伟芳 《实验室研究与探索》2009,28(7):22-24,71
巨磁电阻在测量微弱磁场的变化较其他传感器具有体积小、灵敏度高等优点.比较了多层膜巨磁电阻和自旋阀巨磁电阻的区别,按其特性设计一个采用自旋阀巨磁电阻的位移传感器,并用此位移传感器精确测量金属的线膨胀系数.与各大高校在此实验中用普通方法测金属线膨胀系数的方法相比,该自旋阀巨磁电阻位移传感器测量金属线膨胀系数的方法有操作简便、测量精确,以及将力学量用电学量测量,并将物理数字化,便于电脑采集等优点. 相似文献
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设计了应用TiNi形状记忆合金环作耗能元件的被动减振装置,并对装置的力学和减振性能进行了初步评价.对加载和卸载过程中力-位移曲线进行了研究,当不对环水平方向的变形进行约束时,力-位移曲线为近似于直线且接近重合的2条曲线;若应用滑块对环水平方向的变形进行约束,在力-位移曲线上能形成滞回环,且随位移增加变得更饱满.滞回环的加载和卸载部分不与横坐标平行,而是2条斜线,装置受力时的这种变形特点,可提高装置的抗过载能力.增加环的数量,在相同位移时装置的耗能量明显增加. 相似文献
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彭晓兰 《郧阳师范高等专科学校学报》2003,23(8):83-86,119
进水口变形监测项目包括水平位移简网、垂直位移简网、10个监测点。主要介绍监测网的网型设计、标墩建造、外业施测方法、内业数据处理、平差计算，以及观测资料分析。 相似文献
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在隧道工程中,管棚支护是控制地面沉降和限制隧道变形的有效措施。以晋祠隧道穿越大运高速公路段为例,采用水平测斜管对管棚支护的变形进行监测,通过内设的钢筋计获得管棚支护的受力信息。结果表明：管棚的垂向位移沿隧道开挖线呈凹槽形分布,且沉降量随开挖面的推进不断向前和向下运动,隧道开挖一部和三部时引起的沉降量最大;管棚的内力也具有类似的变化规律,且内力值在开挖面通过后产生明显的回弹,表明管棚超前支护作用显现,调整了围岩的压力。研究结果为类似工程的管棚超前支护设计和监测提供了依据。 相似文献
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管振祥 《石家庄铁路工程职业技术学院学报》2003,2(2):45-49
新松树湾隧道位于砂粘土中，含水量大，土体的稳定性极差，施工难度较大。为此，在隧道施工期间，通过土工试验、隧道收敛和围岩内部位移的现场监测、隧道变形的三维有限元仿真计算等手段，对该隧道的变形进行了系统研究，获得了大量试验数据，研究成果对隧道的施工组织和支护参数的确定起到了重要作用，同时为此类隧道的施工积累了经验。 相似文献
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高地应力条件下软岩大变形隧道极限位移计算模拟 总被引：2，自引：0，他引：2
由于受地应力水平和围岩工程性质影响，高地应力条件下软岩隧道开挖后围岩塑性变形显著，施工中常伴有支护变形侵限、大面积开裂，甚至坍塌等现象发生。如何选择合理的支护措施，有效控制软岩隧道变形并确保结构安全已成为目前地下工程界的关注焦点．施工中各阶段隧道极限位移的研究，可为该种条件下隧道设计和施工决策提供有利的技术支持．根据乌鞘岭隧道F7断层区段的实际情况、对高地应力条件下软岩大变形隧道不同施工阶段的极限位移进行研究和确定，并将研究成效应用于工程实际。 相似文献
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某隧道下穿高速公路段以140m超长大管棚作为超前预支护.为探究隧道开挖过程中管棚与围岩的相互作用,采用测斜仪和水平测斜管对超长大管棚的变形进行测试,得到管棚在隧道开挖过程中各点的位移的分布规律,应用双参数弹性地基梁中的巴氏(Pasternak)模型进行理论分析,并与试验结果进行对比.根据现场测试结果和理论计算,分析隧道在开挖过程中围岩与管棚支护的作用机制,研究结果为以后类似工程的施工提供了借鉴. 相似文献
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A measurement model based on torsion pendulum was established,in which nonlinear damping and nonlinear restoring force were considered.The calculation method of the moment of inertia was based on Hilbert transform.The motion of torsion pendulum showed the time-frequency characteristics due to the nonlinear factors,which were validated by the experimental data.The analytical signal was formed by Hilbert transform of the angular displacement signal of the test object.The moment of inertia can be computed by the instantaneous undamped natural frequency with Hilbert transform.Prior to the implementation of Hilbert transform,the empirical mode decomposition was used to filter the experimental signal.The moment of inertia of the test object was measured by the torsion pendulum system.The experimental results show that the relative measurement error of the moment of inertia was within 0.7%,which indicated the validity of the measurement method. 相似文献
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This study examined a psychosocial mechanism of how general self-efficacy interacts with other key factors and influences degree aspiration for students enrolled in an urban diverse community college. Using general self-efficacy scales, the authors hypothesized the General Self-efficacy model for Community College students (the GSE-CC model). A Confirmatory factor analysis was used to establish a measurement model in which three general self-efficacies were confirmed along with other latent factors (e.g., social capital, transfer capital, etc.). The GSE-CC model was then tested and finalized via structural equation modeling (SEM) techniques. The results showed that general self-efficacy significantly impacted the degree aspiration both directly and indirectly. In addition, general self-efficacy may serve as a bridge between social capital and transfer capital for community college students. Based on the findings, community college practitioners can generate practical implications to promote positive general self-efficacy among students. Further studies were encouraged to adopt/modify the GSE-CC model and test it across different student groups. 相似文献
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INTRODUCTION Structural damage detection technique addresses the problem of how to locate and detect damage that occurred in a structure by using the observed changes of its dynamic and static characteristics. In recent years, damage assessment of structure has drawn wide attention from various engineering fields. Gen-erally, the existing approaches proposed in this area can be clarified into two major categories: the dy-namic identification methods using dynamic test data and the static … 相似文献
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丁英丽 《辽宁科技学院学报》2003,5(3):21-22
主要介绍了双边联合控制的电液比例变量泵的工作原理，设计了基于单片机的测试系统，并利用此测试系统对电液比例变量泵的静态特性进行了潮试和计算机仿真。 相似文献
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A closed-form out-of-plane dynamic displacement response of a curved track subjected to moving loads was pro- posed. The track structure was modeled as a planar curved Timoshenko beam periodically supported by the double-layer spring-damping elements. The general dynamic displacement response induced by the moving loads along the curve on the elastic semi-infinite space was firstly obtained in the frequency domain, according to the Duhamel integral and the dynamic reciprocity theorem. In the case of the periodic curved track structure subjected to moving loads, the dynamic displacement equation was simplified into a form of summation within the basic track cell instead of the integral. The transfer function for the curved track was expressed in the form of a transfer matrix. Single and series moving loads were involved in the calculation program. For the verification of the analytical model, the mid-span vertical deflection of a simply support curved beam subjected to moving load was recalculated and compared with the same case in the reference. The research results indicate that： under the same moving loads, the displacement response of the curved track decreases slightly with the increasing track radius, and the displacement response of the curved track with the radius greater than or equal to 600 m is almost equivalent to the displacement response of the straight track; the frequency spectrum of the curved track is more abundant than that of the straight track, which may result in more wheel-rail resonance and rail corrugation in the curved lines. 相似文献
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计算机散斑干涉法在位移测量中的应用 总被引：2，自引：0，他引：2
基于计算机散斑干涉法的原理进行平面内位移测量，采用亚像素法、附加矢量法和中心偏移法提高了精度，使该方法更具实用性，并以实验验证。结果表明，计算机散斑干涉法应用在位移测量中，误差相近于其它方法，然而具有远距测量、非接触、全场测量等独特的优点，再有对环境要求不高、成本较低、可编程等有利条件，使该方法有良好的应用前景。 相似文献
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We developed a measuring instrument that had wide range, high precision, small measuring touch force. The instrument for three-dimensional （3D） surface topography measurement was composed of a high precision displacement sensor based on the Michelson interference principle, a 3D platform based on vertical scanning, a measuring and control circuit, and an industrial control computer. It was a closed loop control system, which changed the traditional moving stylus scanning style into a moving platform scanning style. When the workpiece was measured, the lever of the displacement sensor returned to the balanced position in every sample interval according to the zero offset of the displacement sensor. The non-linear error caused by the rotation of the lever was, therefore, very small even if the measuring range was wide. The instrument can measure the roughness and the profile size of a curved surface. 相似文献
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The grating eddy current displacement sensor （GECDS） for distance or position measurement used in watertight electronic calipers was described. The sensor relies on repetitive variation of inductance against displacement caused by the change of coupling areas between moving coils and static reflectors. The investigations focused on setting up and utilizing a computer model of the 3D eddy current fields and geometry to analyze causes of the production of measurement blind areas, and to investigate effects of the sensor parameters, such as axial gap between coils and reflectors, reflector length and reflector width on characteristics of the sensor. Simulation results indicated that the sensor has the smallest nonlinearity error of 0.15%, which agrees well with the experimental results. 相似文献