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1.
The limited research on the geopolymer concrete mix design for targeting a specific strength is identified an obstacle for their effective design and wide use. In this paper, a mix design procedure has been proposed for fly-ash based geopolymer concrete and its use as infill hybrid composite beam is investigated. Then, the structural performance of geopolymer concrete filled hybrid composite beam is investigated to determine their possible application in civil infrastructure. Firstly, a detailed procedure of mix design for fly-ash based geopolymer concrete is presented. Secondly, three hybrid beams filled with geopolymer concrete were prepared and tested in a four-point bending setup to evaluate their flexural modulus and modulus of rupture. Numerical and analytical evaluation of the behaviour of hybrid beam were performed and results showed a good agreement with the experimental investigation. Thirdly, the suitability of the beam for a composite railway sleeper is evaluated and compared with existing timber and composite sleepers. Finally, the beams’ performance in a ballast railway track is analysed using Strand7 finite element simulation software and the results showed that the new concept of using geopolymer concrete as infill to pultruded composite section satisfied the stiffness and strength requirements for a railway sleeper. 相似文献
2.
《International Journal of Hydrogen Energy》2020,45(56):31689-31705
Kriging model has been widely used to approximate expensive black-box problems in many engineering design fields. How to choose an appropriate sampling strategy to produce new expensive updated points is crucial. For this purpose, an adaptive Kriging method with double sampling criteria (AKM-DSC) is proposed. During every iteration of it, maximum curvature criterion and maximum variance criterion based on Kriging model are respectively optimized by trust region (TR) strategy to produce two candidate points. And then, a new screening method is used to determine final expensive-evaluation points from the two candidates. The proposed method is compared with the two typical Kriging modeling methods. The comparison results of seventeen benchmark functions verify that the proposed method can generate higher accuracy Kriging model. Finally, a hydrogen preparation case illustrates the engineering application value of the AKM-DSC method. 相似文献
3.
Guohua Sun Ruoquan He Gu Qiang Youzhen Fang 《Journal of Constructional Steel Research》2011,67(12):1821-1834
In order to investigate the behavior of partially-restrained steel frame with RC infill wall (PSRCW), two specimens with one-third scale, one-bay, and two-story were performed under reversed cyclic lateral load, where one specimen was with concealed vertical slits in the infill walls and another specimen with solid infill walls. Test results showed that both specimens obtained enough lateral stiffness for controlling drift and yielded enough strength appropriate for resisting lateral load. PSRCW with solid infill walls exhibited moderate ductility capacity and energy dissipation due to the degradation of post-peak strength. PSRCW with concealed vertical slits exhibited much larger ductility, deformability, and energy dissipation capacity than the other one. Once concealed vertical slits were crushed, infill walls behaved as a series of flexural columns provided fairly ductile response and stable cyclic performance. PSRCW with concealed vertical slits can improve post-peak strength degradation considerably. In addition, damaged PSRCW structure subjected to earthquake is easy to be repaired, through knocking off the heavy crushed infill walls and recasting concrete infill walls. This is another advantage of this composite structure. 相似文献
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基于Kriging元模型的优化方法通常存在优化效率较低、收敛速度较慢、昂贵估值次数较多且难以有效平衡Kriging模型的局部与全局搜索行为等弊端。为此,提出一种序列Kriging和距离因子辅助的全局优化方法。其实现过程主要包含两个阶段:一是利用Kriging模型近似复杂昂贵的黑箱函数;二是利用Kriging模型与距离因子的乘积构造加点采样法则,并通过免于求导的DIRECT算法优化该法则,以获取新的昂贵估值点。六个数值函数测试和一个摆线泵仿真实例验证所提出方法的有效性。 相似文献
6.
由于河南油田稠油油藏具有“浅、薄、稠、散”的特点,所以蒸汽吞吐平均6个周期后,开发指标和经济指标明显降低。蒸汽吞吐后剩余油分布为:100m×141m及五点法并网,剩余油分布较为集中,100m×100m反七点法并网,剩余油分布零散;经济分析结果表明:浅薄层稠油油藏加密井吞吐单井的经济极限产量为1200~1500t,当油层厚度大于5.0m、纯总厚度比大于0.5,以及单井控制死油区面积大于0.5×10-2km2,且死油区离边水距离大于150m时,可进行加密,加密井蒸汽吞吐采收率可达14%左右。不同并网的加密方式为:100m×141m及五点法井网,采用直并加密方式;100m×100m反七点法并网,采用水平并加密方式。 相似文献
7.
H. Rodrigues H. Varum A. Costa 《International Journal of Mechanics and Materials in Design》2008,4(2):123-135
The presence of masonry infill walls in RC buildings is very common. However, and even today, in the design of new buildings
and in the assessment of existing ones, these infill walls are usually considered as non-structural elements and their influence
in the structural response is generally ignored. For horizontal loading, infill panels can drastically modify the response,
attracting forces to parts of the structure that have not been designed to resist them. This paper presents an improved non-linear
numerical simulation model for the influence of the masonry infill walls in the seismic behavior of structure. The model is
implemented in the PORANL program. After the implementation and calibration of the proposed masonry model, a series of non-linear
dynamic analyses of a building representative of Modern Architecture in Europe were carried out. The main objective was to
investigate the behavior of this type of building, and any weakness under seismic loading. The building geometry and the dimensions
of the RC elements and infill walls were set in the original project, and confirmed in the technical visits. The building
under study has nine storeys and the structure is mainly composed of 12 plane frames oriented in the transversal direction.
The building was analyzed with a simplified plane model, for each direction, and the existing infill panels were looked at
in accordance with their dimensions and location. The earthquake action adopted in this study was simulated through three
series of artificially generated earthquakes, for a medium/high seismic risk scenario in Europe. 相似文献
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加密井的压裂时机直接影响着页岩气藏最终的开发效果。为了有效地指导页岩气藏加密井部署与压裂施工,基于离散裂缝网络模型、有限差分模型及有限元模型,提出了一套页岩气藏加密井压裂时机优化方法:根据页岩气田开发现状及井网加密需求,系统考虑储层非均质性和天然裂缝发育特征,建立渗流—地质力学耦合条件下四维地应力演化及复杂裂缝扩展的多物理场模型,进而模拟加密井水力裂缝扩展形态、加密井及井组开发效果,最终优选出加密井最佳的压裂时机。以四川盆地涪陵页岩气田X1井组为例,利用该优化方法研究了加密井压裂时机和施工参数对其复杂裂缝扩展形态、单井及井组产能的影响规律。结论认为:①该优化方法能够有效模拟老井生产过程中储层物性及力学状态变化,预测压后产量变化,优选加密井压裂参数及压裂时机;②当加密井射孔簇间距减小、每簇施工液量增大时,水力压裂改造体积、裂缝密度增大,压裂后产量提高,但射孔簇间距过小、每簇施工液量过大时,则有可能会导致分支裂缝串通和重叠,降低压裂液效率、影响压裂后产能;③压裂时机越晚,加密井井筒附近分支裂缝越密集,但改造体积越小、初期产量越低;④当目标井组生产36个月进行加密井压裂时,井组累计页岩气产量最高、开发效果最优。 相似文献
10.
通过对高含水后期加密调整井特点及其指标预测的特殊性研究,提出了随机模拟地质模型建模的原则 基础上,采用油藏数值模拟和预测放大方法较好地解决了加密调整井指标预测问题。 相似文献