科创中国

对外径为Ф10mm碳纤维复合材料管成型工艺及性能进行了研究.结果表明,采用热缩工艺成型的碳纤维复合材料管工艺简单、质量可靠,Ф10mm碳纤维复合材料管件弯曲刚度与不锈钢管相当,弯曲强度为不锈钢的3倍以上,质量仅为不锈钢的50%,尺寸精度满足设计要求.

Fiber reinforced polymer (FRP) composite materials having advantages such as higher strength to weight than conventional engineering materials, non-corrosiveness and modularization, which should help engineers to obtain more efficient and cost effective structural materials and systems. Currently, FRP composites are becoming more popular in civil engineering applications. The objectives of this research are to study performance and behavior of light weight multi-cellular FRP composite bridge decks (both module and system levels) under various loading conditions through finite element modeling, and to validate analytical response of FRP composite bridge decks with data from laboratory evaluations. The relative deflection, equivalent flexural rigidity, failure load (mode) and load distribution factors (LDF) based on FE results have been compared with experimental data and discussed in detail. The finite element results showing good correlations with experimental data are presented in this work.

The strain distributions near the interface when the elbow steel fiber is pulled out from the half-mould concrete matrix are directly measured using a combined method of single fiber pull-out test and digital image correlation. Meanwhile, the real-time processes of the bonding, debonding and sliding at the interface are observed. The micro-mechanism of the strain localization in the failure process of interface when debonding occurs and the strengthening mechanism at the imbedded fiber are discussed. The experimental results show that the meso-scale strain localization gives rise to the localization of shear damage near the fiber interface. This strain localization characterized by the debonding process near the interface occurs, develops and moves gradually at an apparently regular interval. At the elbow part of the imbedded fiber, the peak value of the shearing stress occurs. But the primary debonding does not occur at this place because the strength of the shear damage is increased at the local area of the elbow part in the concrete, displaying an apparent reinforced effect at the end of the fiber.

选用碳纤维(CF)、玻璃纤维(GF)和高强玻璃纤维(SGF)为增强材料,制作CF,CF/GF和CF/SGF层间组合混杂纤维增强木梁,并对其受弯性能进行了试验研究,同时分析了该木梁的破坏形态和破坏机理,讨论了其荷载-位移特征、极限承载力和延性.结果表明:与单一CF增强相比,合理匹配混杂纤维增强复合材料(HFRP)可显著提高木梁的承载力和延性.提出了HFRP增强木梁的极限承载力计算方法.

通过阐述逆向物流产生的背景及成因,分析在低碳经济环境下逆向物流的有形和无形经济价值以及保护生态环境和节约资源的环境价值.针对我国逆向物流的现状,提出在低碳经济下发展逆向物流的几点建议.

Eddy current pulsed thermography(ECPT) is an emerging Non-destructive testing and evaluation(NDT & E) technique, which uses hybrid eddy current and thermography NDT & E techniques that enhances the detectability from their compensation. Currently, this technique is limited by the manual selection of proper contrast frames and the issue of improving the efficiency of defect detection of complex structure samples remains a challenge. In order to select a specific frame from transient thermal image sequences to maximize the contrast of thermal variation and defect pattern from complex structure samples, an energy driven approach to compute the coefficient energy of wavelet transform is proposed which has the potential of automatically selecting both optimal transient frame and spatial scale for defect detection using ECPT. According to analysis of the variation of different frequency component and the comparison study of the detection performance of different scale and wavelets, the frame at the end of heating phase is automatically selected as an optimal transient frame for defect detection. In addition, the detection capabilities of the complex structure samples can be enhanced through proper spatial scale and wavelet selection. The proposed method has successfully been applied to low speed impact damage detection of carbon fibre reinforced polymer(CFRP) composite as well as providing the guidance to improve the detectability of ECPT technique.

通过试验研究了聚丙烯(PP)纤维和植物纤维素(UFPP)纤维对受荷混凝土渗透性能的影响.结果表明:在一定荷载范围内,纤维混凝土的抗渗能力有所提高,当荷载超过混凝土破坏荷载30%左右时,其抗渗能力随之下降.同时研究了纤维对各龄期混凝土抗氯离子渗透性能及抗冻融循环耐久性能的影响,并分析了其机理.

UV固化不仅可以使复合材料快速固化,而且不需要高温,能避免残余热应力的产生,在应急抢修中比通常的热固化复合材料更具优势.本文采用UV固化的方法实现了损伤金属结构的快速修复,分析了复合材料补片的铺设层数、长度以及损伤结构表面处理对修复效果的影响.

通过模拟水管式沉降仪埋设安装条件,按照监测规范及相关技术要求,结合水管式沉降仪测值计算及修正原理,对糯扎渡水电站水管式沉降仪模拟实验场地布置、材料要求、安装及坝料回填过程进行实验.监测数据结果表明,实验测点最大沉降分别为145 mm和37 mm,水管式沉降仪器整体测值稳定,波动变化较小,对于在糯扎渡高土石坝具有良好的适用性.

采用废旧聚乙烯(PE)与硫酸钙晶须为原料,通过熔融挤出共混制得废旧PE/硫酸钙晶须复合材料,比较了经硅烷偶联剂KH-590改性与未改性的硫酸钙晶须用量对废旧PE/硫酸钙晶须复合材料力学性能的影响,分析硫酸钙晶须增强度旧PE的机理和废旧PE/硫酸钙晶须复合材料的微观结构.结果表明:当硫酸钙晶须用量为15%时,未改性硫酸钙晶须使复合材料的拉伸强度、冲击强度提高了23.1%、9.1%;改性硫酸钙晶须使复合材料的拉伸强度、冲击强度、弯曲强度提高了26.7%、15.6%和5 3%,其在废旧PE中分布均匀,能起到明显的增强作用.