Numerical Cracking and Debonding Analysis of RC Beams Reinforced with FRP Sheet

Bonding a fiber reinforced polymer (FRP) sheet to the tension-side surface of reinforced concrete (RC) structures is often performed to upgrade the flexural capacity and stiffness. Except for upper concrete crushing, FRP sheet reinforcing RC structure may fail in sheet rupture, sheet peeloff failure due to opening of a critical diagonal crack, or concrete cover delamination failure from the sheet end. Accompanying the occurrence of these failure modes, reinforcing effects of the FRP sheet will be lost and load-carrying capacity of the RC structures will be decreased suddenly. This study is devoted to developing a numerical analysis method by using a three-dimensional elasto-plastic finite element method to simulate the load-carrying capacity of RC beams failed in the FRP sheet peeloff mode. Here, the discrete crack approach was employed to consider geometrical discontinuities such as opening of cracks, slipping of rebar, and debonding of the FRP sheet. Comparisons between analytical and experimental results confirm that the proposed numerical analysis method is appropriate for estimating the load-carrying capacity and failure behavior of RC beams flexurally reinforced with a FRP sheet.     

贵冶控制网主干改造

本文简要介绍了贵冶控制网及控制网改造的原则,并对网络改造后采取的提高网络可靠性的方法进行了说明。     

Development of smart composite structures with small-diameter fiber Bragg grating sensors for damage detection: Quantitative evaluation of delamination length in CFRP laminates using Lamb wave sensing

The authors and Hitachi Cable, Ltd. have recently developed small-diameter optical fiber and its fiber Bragg grating (FBG) sensor for embedment inside a lamina of composite laminates without strength reduction. The outside diameters of the cladding and polyimide coating are 40 and 52 μm, respectively. First, a brief summary is presented for applications of small-diameter FBG sensors to damage monitoring in composite structures. Then, we propose a new damage detection system for quantitative evaluation of delamination length in CFRP laminates using Lamb wave sensing. In this system, a piezo-ceramic actuator generates Lamb waves in a CFRP laminate. After the waves propagate in the laminate, transmitted waves are received by an FBG sensor attached on or embedded in the laminate using a newly developed high-speed optical wavelength interrogation system. This system was applied to detect interlaminar delamination in CFRP cross-ply laminates. When the Lamb waves passed through the delamination, the amplitude decreased and a new wave mode appeared. These phenomena could be well simulated using a finite element analysis. From the changes in the amplitude ratio and the arrival time of the new mode depending on the delamination length, it was found that this system could evaluate the delamination length quantitatively. Furthermore, small-diameter FBG sensors were embedded in a double-lap type coupon specimen, and the debonding progress could be evaluated using the wavelet transform.     

有载调压变压器直流电阻异常分析

通过对一起有载调压变压器直流电阻不平衡故障分析，总结经验，提出解决措施以便更好地做好有载调压变压器的检修工作。     

百里香酚蓝光导纤维酸度传感器的研制

将百里香酚蓝固定在Nafion膜上，以此为敏感膜研制的光导纤维酸度传感器，具有响应迅速可逆、稳定性好、选择性高的优点，适用于pH3．7～0范围酸度的传感监测及0．001-mol／L以上HF浓度的快速测定．     

刻纹光纤传感阵列及其神经网络处理──适用于结构状态探测与损伤估计

提出了一种新颖的、采用周期性对称刻纹多模光纤组成的传感阵列网络，可用于智能材料与结构的应力、应变等的状态探测或损伤估计。探索了采用人工神经网络处理其阵列传感信号的原理与技术，并给出了BP网仿真结果。     

阻燃纤维

本文综述了纤维的阻燃机理，阻燃方法，以及阻燃纺织品的应用，同时介绍了近期阻燃纤维的品种，并指出阻燃纺织品在我国有着巨大的市场。     

特高压环境下OPGW耐雷性能分析

我国目前正在开展的特高压电网,由于线路参数发生变化,对OPGW的耐雷性能将提出更高的要求,在实践工程中应重点考虑。文章首先简要介绍了特高压电网的基本概念,分析了在特高压环境下OPGW在雷击性能方面与超高压环境的主要区别,并通过一些计算比较得出在特高压环境下由于引雷概率增大,则相应地提高OPGW耐雷能力的结论。     

光纤光栅传感器的解调方法的研究

本文论述了光纤光栅传感系统的解调方法。首先本文论述了光栅传感系统的解调趋势．然后理论分析了光纤光栅的传感原理。接着从3个方面介绍了传感系统的信号解调技术，即滤波溶调技术，可调窄带解调技术和色散解调技术，并对以上各种解调技术的优点和缺点进行了论述，并提出一较有前景的解调方法。