基于BIM技术和有限元的检测与分析在PC结构中的应用研究

本文建立了PC结构施工全过程的BIM模型及有限元分析模型,对施工过程进行数值模拟与动态、静态监测,对装配式结构进行了结构性能评价,为结构可视化施工监测提供了技术支持。     

Design and Analysis of New Micromixers Based on Distillation Column Trays

Four passive micromixer designs (G1, G2, G3, and G4) based on distillation columns trays are proposed. The performance of the devices is assessed by numerical simulations. The mixing performance is investigated for different Reynolds numbers and channel heights for oil/ethanol flow. G1 and G4 designs provided a high mixing index. The G1 device achieved superior mixing performance with a moderate pressure drop due to the induced flow recirculation pattern for a relatively high flow rate, highlighting the potential use of such microdevice for scale-up and numbering-up of microdevices in modular chemical plant processing.     

中空夹层金属管混凝土构件侧向冲击试验研究

为提高海洋平台结构的抗冰能力，提出一种新型中空夹层金属管混凝土导管腿构件。通过理论分析、数值模拟和试验相结合，研究不同外钢管材料（Q345钢、奥氏体304级不锈钢和T6061铝合金）对中空夹层钢管混凝土构件的影响。通过单次冲击和连续冲击两种加载方式进行加载，并与钢质空心导管腿进行对比，试验结果发现：组合构件抗冲击性能优于空管构件，铝合金组合构件整体抗冲击能力较差，不锈钢单次冲击作用下极限承载能量高达18.83 kJ以上，小能量连续冲击作用下承载冲击次数最多，不锈钢组合构件抗冲击力学性能最好。结合有限元ABAQUS软件，对单次冲击构件建模并得出计算结果，与试验结果基本吻合。     

小样产品试织时常见问题处理的探讨

本文结合多年的实践经验，针对纺织专业学生使用江阴通源生产的SGA598型半自动织样机设计试织时，出现的松紧边、锁边问题、张力控制等常见问题进行了探讨。     

Image analysis applications on assessing static stability and flowability of self-consolidating concrete

A digital image processing (DIP) method associated with a MATLAB algorithm is used to evaluate cross sectional images of self-consolidating concrete (SCC). Two new parameters, such as inter-particle spacing of coarse aggregate and average mortar-to-coarse aggregate ratio, defined as average mortar thickness index (MTI), were proposed to quantitatively evaluate the static stability of SCC. Statistical models were developed to predict flowability of SCC mixtures. Test results revealed that the proposed DIP method and MATLAB algorithm can be successfully used to derive inter-particle spacing and MTI and quantitatively evaluate the static stability on hardened SCC samples. A probability density of 60% from histogram analysis appears to be a reasonable threshold for indicating a uniformly distributed SCC mixture. For a given mortar yield stress, a critical mortar viscosity of 1.30 Pa s tends to significantly affect the trend of slump flow changing with MTI. The investigated relationship between parameters measured from DIP method and existing theoretical frames is well correlated. The outcome of this study can be of practical value for providing an efficient and useful tool in designing mixture proportions of SCC.     

Recovery of phosphate ores in the modified three-product column (3PC) flotation cell

This work details the results obtained for the rougher flotation of phosphates in a modified flotation cell known as a three-product column (3PC), at both the laboratory and pilot plant scales. Results were compared to a conventional column cell-CCC. The 3PC cell separates the drained (rejected) particles from the froth zone (third product) and uses a secondary wash water system between the feed and the froth zone (II). Bench-scale studies measured the effect of the two water surface rates on mass and metallurgical recoveries and concentrate grades (P₂O₅, Fe₂O₃, and SiO₂) in all the flows. At pilot scale, the influence of wash water (J_W2) and column design on the flotation separation parameters was studied. Results showed that, compared with the conventional column cell (CCC), the 3PC yielded, in all cases, clean high-grade concentrates, with a minor concentration of impurities (Fe₂O₃ and SiO₂). Concentrate recoveries ranged from 40% to 70% for apatite and were lower when compared to CCC, but it is believed that the third product could be recycled to the fee. This drop-back product operating with J_W2 = 0.0 cm s⁻¹ might yield 5–10% extra in apatite recoveries and enhancing this J_W2 values, the apatite recovery decreased by 0.5–3% but rejection of impurities was very high. Results appear to show that the 3PC may be used as a rougher-flash or Cleaner unit with an optional recycle of the third product into the rougher or simply discarding it. Data on the influence of some cell design and gas dispersion parameters on process efficiency are reported, and the potential practical applications for this type of cell are envisaged.     

Numerical Simulation of Interfacial Closures for 3D Bubble Column Flows

Numerical investigation of flow hydrodynamics in a square cross‐sectioned bubble column was conducted in a transient Euler‐Euler environment by applying the simulation tool Ansys CFX 14.0. The influence of the drag coefficient (C_D) was investigated and the results were also compared with drag force models. Furthermore, three different lift force models and a defined lift coefficient were studied. All results were compared with the available experimental data. All simulations were carried out for a single‐hole sparger with given aspect ratio (H/D) and superficial gas velocity.     

绿色合成型混凝土的弹性恢复机制研究

研究了绿色合成型混凝土的弹性恢复性能,结果表明,在满足安全储备的情况下,可充分利用混凝土材料。     

Complex concrete structures: Merging existing casting techniques with digital fabrication

Over the course of the 20th century, architectural construction has gone through intense innovation in its material, engineering and design, radically transforming the way buildings were and are conceived. Technological and industrial advances enabled and challenged architects, engineers and constructors to build increasingly complex architectural structures from concrete. Computer-aided design and manufacturing (CAD/CAM) techniques have, more recently, rejuvenated and increased the possibilities of realizing ever more complex geometries. Reinforced concrete is often chosen for such structures as almost any shape can be achieved when placed into a formwork. However, most complex forms generated with these digital design tools bear little relation to the default modes of production used in concrete construction today. A large gap has emerged between the possibilities offered by the digital technology in architectural design and the reality of the building industry, where actually no efficient solutions exist for the production of complex concrete structures. This paper presents construction methods that unfold their full potential by linking digital design, additive fabrication and material properties and hence allow accommodating the construction of complex concrete structures. The emphasis is set on the on-going research project Smart Dynamic Casting (SDC) where advanced material design and robotic fabrication are interconnected in the design and fabrication process of complex concrete structures. The proposed fabrication process is belonging to an emerging architectural phenomenon defined first as Digital Materiality by Gramazio & Kohler (2008) or more recently as Material Ecologies by Neri Oxman  [1].