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Computational simulation methods for fiber reinforced composites

Vladimír KOMPI, Zuzana MURINKOV, Sergey RJASANOW, Richards GRZIBOVSKIS, Qinghua QIN,

《结构与土木工程前沿（英文）》 2010年第4卷第3期页码 396-401 doi: 10.1007/s11709-010-0079-1

摘要： Trefftz-finite element method (Trefftz-FEM), adaptive cross approximation BEM (ACA BEM) and continuous source function method (CSFM) are used for the simulation of composites reinforced by short fibers (CRSF) with the aim of showing the possibilities of reducing the problem of complicated and important interactions in such composite materials.

关键词： Trefftz-finite element method (Trefftz-FEM) adaptive cross approximation BEM (ACA BEM) method of continuous source functions composite materials short fibers

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Independent continuous and mapping method of structural topology optimization based on the global stress

Yunkang SUI, Jili FENG, Hongling YE, Xirong PENG,

《机械工程前沿（英文）》 2010年第5卷第2期页码 130-142 doi: 10.1007/s11465-010-0011-3

摘要： There are three difficulties in topology optimization of continuum structures. 1) The topology under multiple load case is more difficult to be optimized than under single load case, because the former becomes a multiple objective based on compliance objective functions. 2) With local constraints, such as an elemental stress limit, the topology is more difficult to be solved than with global constraints, such as the displacement or frequency limits, because the sensitivity analysis of the former has very expensive computation. 3) With the phenomenon of load illness, which is similar with stiffness illness in the structural analysis, it is not easy to get the reasonable final topological structure, because it is difficult to consider different influences between the loads with small forces and big forces, and some topology paths of transferring small forces may disappear during the iteration process. To overcome difficulties above, four measures are adopted. 1) Topology optimization model is established by independent continuous mapping (ICM) method. 2) Based on the von Mises strength theory, all elements’ stress constraints are transformed into a structural energy constraint. 3) The phenomenon of load illness is divided to classify into three cases. 4) A strategy based on strain energy is proposed to adopt ICM method with stress globalization, and the problems of the above mentioned three cases of load illness are solved in terms of different complementary approaches. Several numerical examples show that the topology path of transferring forces can be obtained more easily by substituting global strain energy constraints for local stresses constraints, and the problem of load illness can be solved well by the weighting method that takes the structural energy as a weighting coefficient.

关键词： independent continuous mapping (ICM) method global stresses constraints topology optimization continuum structure load illness

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A continuous/discontinuous deformation analysis (CDDA) method based on deformable blocks for fracture

Yongchang CAI, Hehua ZHU, Xiaoying ZHUANG

《结构与土木工程前沿（英文）》 2013年第7卷第4期页码 369-378 doi: 10.1007/s11709-013-0222-x

摘要： In the framework of finite element meshes, a novel continuous/discontinuous deformation analysis (CDDA) method is proposed in this paper for modeling of crack problems. In the present CDDA, simple polynomial interpolations are defined at the deformable block elements, and a link element is employed to connect the adjacent block elements. The CDDA is particularly suitable for modeling the fracture propagation because the switch from continuous deformation analysis to discontinuous deformation analysis is natural and convenient without additional procedures. The SIFs (stress intensity factors) for various types of cracks, such as kinked cracks or curved cracks, can be easily computed in the CDDA by using the virtual crack extension technique (VCET). Both the formulation and implementation of the VCET in CDDA are simple and straightforward. Numerical examples indicate that the present CDDA can obtain high accuracy in SIF results with simple polynomial interpolations and insensitive to mesh sizes, and can automatically simulate the crack propagation without degrading accuracy.

关键词： fracture crack propagation deformable block continuous/discontinuous deformation analysis (CDDA)

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A method for quantifying bias in modeled concentrations and source impacts for secondary particulate

Cesunica E. Ivey, Heather A. Holmes, Yongtao Hu, James A. Mulholland, Armistead G. Russell

《环境科学与工程前沿（英文）》 2016年第10卷第5期 doi: 10.1007/s11783-016-0866-6

摘要： A method for quantifying source impacts for secondary PM species is derived. The method provides estimates of bias in modeled concentrations. Adjusted concentrations match corresponding observations at monitored locations. Sources impacts on secondary species are estimated over the US for 20 sources. Community Multi-Scale Air Quality (CMAQ) estimates of sulfates, nitrates, ammonium, and organic carbon are highly influenced by uncertainties in modeled secondary formation processes, such as chemical mechanisms, volatilization, and condensation rates. These compounds constitute the majority of PM mass, and reducing bias in estimated concentrations has benefits for policy measures and epidemiological studies. In this work, a method for adjusting source impacts on secondary species is developed that provides estimates of source contributions and reduces bias in modeled concentrations compared to observations. The bias correction adjusts concentrations and source impacts based on the difference between modeled concentrations and observations while taking into account uncertainties at the location of interest; and it is applied both spatially and temporally. We apply the method over the US for 2006. The mean bias for initial CMAQ concentrations compared to observations is −0.28 (OC), 0.11 (NO ), 0.05 (NH ), and −0.08 (SO ). The normalized mean bias in modeled concentrations compared to observations was effectively zero for OC, NO , NH , and SO after applying the secondary bias correction. 10-fold cross-validation was conducted to determine the performance of the spatial application of the bias correction. Cross-validation performance was favorable; correlation coefficients were greater than 0.69 for all species when comparing observations and concentrations based on kriged correction factors. The methods presented here address model uncertainties by improving simulated concentrations and source impacts of secondary particulate matter through data assimilation. Secondary-adjusted concentrations and source impacts from 20 emissions sources are generated for 2006 over continental US.

关键词： Particulate matter Source apportionment Secondary particulate matter Chemical transport modeling Receptor modeling

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城市大气污染源追踪“广义判识”与Nudging源同化集成技术途径

徐祥德,丁国安

《中国工程科学》 2012年第14卷第10期页码 10-22

摘要：

提出了城市大气污染源追踪“广义判识”综合应用平台、模式源同化及其卫星遥感应用等新技术。“广义判识”综合应用平台包括气溶胶源主因子分析方法、气溶胶周期变化谱分析法、城市冠层大气污染变化规律同位相特性分析、追溯远距离空气污染源的合成风场相关矢量法、后向轨迹示踪法和边界层影响足痕分析法；另外，为解决长期以来大气污染模式中排放源不确定性的关键技术难点，采用源同化牛顿逼近Nudging技术，获取具有季节、月变化动态变化特征的SO2、NO2区域反演源排放清单。将卫星遥感资料应用在同化模型，探索空气污染预报模式的卫星遥感产品应用技术，卫星遥感—地基观测综合分析平台亦可广泛地应用于城市污染源追踪、城市雾和城市热岛的研究，并提出多圈层水—土—气综合分析方法是一种追踪水污染源的探索性尝试

关键词：广义判识源同化污染源追踪卫星遥感—地基水—土—气

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大跨度混凝土连续梁桥的病害成因分析

林帆,王萍,肖开军,李伟

《中国工程科学》 2010年第12卷第4期页码 78-81

摘要：

自20世纪80年代以来，我国建成了大量大跨度预应力混凝土连续体系桥梁，取得了辉煌成就，但随着桥梁建设数量与使用年限的增加，该类桥梁在施工与运营期陆续出现一些具有共性的病害：跨中挠度过大、箱梁开裂与跨中合龙段底板剥离等，而且有些病害已经导致桥梁重大的安全事故与经济损失。文章对国内数十座桥梁出现的病害随时间变化发展的趋势、在空间上分布的形态等进行了分析。根据现有的理论研究成果，分析了腹板斜裂缝、底板纵向裂缝、合龙段底板分层等病害的形成机理，提出了控制裂缝等病害发生的措施，并说明了这些控制措施在泰州大桥预应力桥

关键词：预应力混凝土连续体系桥梁病害控制

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A method of determining flame radiation fraction induced by interaction burning of tri-symmetric propanefires in open space based on weighted multi-point source model

Jie JI, Junrui DUAN, Huaxian WAN

《能源前沿（英文）》 2022年第16卷第6期页码 1017-1026 doi: 10.1007/s11708-020-0716-x

摘要： The interaction of multiple fires may lead to a higher flame height and more intense radiation flux than a single fire, which increases the possibility of flame spread and risks to the surroundings. Experiments were conducted using three burners with identical heat release rates (HRRs) and propane as the fuel at various spacings. The results show that flames change from non-merging to merging as the spacing decreases, which result in a complex evolution of flame height and merging point height. To facilitate the analysis, a novel merging criterion based on the dimensionless spacing / was proposed. For non-merging flames ( / >0.368), the flame height is almost identical to a single fire; for merging flames ( / ≤0.368), based on the relationship between thermal buoyancy and thrust (the pressure difference between the inside and outside of the flame), a quantitative analysis of the flame height, merging point height, and air entrainment was formed, and the calculated merging flame heights show a good agreement with the measured experimental values. Moreover, the multi-point source model was further improved, and radiation fraction of propane was calculated. The data obtained in this study would play an important role in calculating the external radiation of propane fire.

关键词： flame interaction air entrainment flame height multi-point source model thermal radiation

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颗粒物面源模式计算方法

谷清,杨新兴,李云生

《中国工程科学》 2005年第7卷第1期页码 41-44

摘要：

对颗粒物面源模式做了深入研究，确定了颗粒物粒子面源开始沉降的位置。颗粒物粒子在面源内部不考虑沉降问题，面源源块内颗粒物浓度等于单位面积污染物源强与地面反射系数之积除以地面风速。面源源块外面开始考虑粒子沉降，采用虚点源后置法，参考颗粒物点源的部分反射倾斜烟云模式，全面给出了面源的颗粒物模式。面源边缘浓度采用线性内插方法处理，以免计算结果不连续。面源中心点位置应该在水平x，y方向平移一个微小距离，以消除计算点和面源中心点重合的可能。

关键词：大气环境颗粒物面源模式计算方法

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Calculation and analysis of sub/supercritical methanol preheating tube for continuous production of biodiesel

Wen CHEN, Weiyong YING, Cunwen WANG, Weiguo WANG, Yuanxin WU, Junfeng ZHANG,

《能源前沿（英文）》 2009年第3卷第4期页码 423-431 doi: 10.1007/s11708-009-0075-0

摘要： Biodiesel is an important renewable energy. Supercritical methanol transesterification for biodiesel has recently been concerned because of its obvious advantages. The tubular reactor is an ideal reactor for continuous preparation of biodiesel via supercritical methanol transesterification. A methanol preheating tube is necessary for the tubular reaction system because the reaction temperature for supercritical methanol transesterification is usually 520―600K. Therefore, in the range of 298―600K, changes of the density, isobaric capacity, viscosity and thermal conductivity of sub/supercritical methanol with temperature are first discussed. Then on the basis of these thermophysical properties, an integration method is adopted for the design of sub/supercritical methanol preheating tube when methanol is preheated from 298K to 600K at 16MPa and the influencing factors on the length of the preheating tube are also studied. The computational results show that the Reynolds number and the local convection heat-transfer coefficient of sub/supercritical methanol flowing in ф6mm×1.5mm preheating tube change drastically with temperature. For the local overall heat transfer coefficient and the average overall heat transfer coefficient , temperature also has an important influence on them when the inlet velocity of methanol is lower than 0.5m/s. But when the inlet velocity of methanol is higher than 0.5m/s, and almost keep invariable with temperature. Additionally, both the outlet temperature and the inlet velocity of methanol are the key affecting factors for the length of the preheating tube, especially when the outlet temperature is over the critical temperature of methanol. At the same time, the increase of tin bath’s temperature can shorten the required length of the preheating tube. At the inlet flow rate of 0.5m/s, the required length of the preheating tube is 2.0m when methanol is preheated from 298K to 590K at 16MPa with keeping the tin bath’s temperature 620K, which is in good agreement with the experimental results.

关键词： sub/supercritical methanol preheating tube integration method biodiesel

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Strain and process engineering toward continuous industrial fermentation

《化学科学与工程前沿（英文）》 2023年第17卷第10期页码 1336-1353 doi: 10.1007/s11705-022-2284-6

摘要： Most current biotechnology industries are based on batch or fed-batch fermentation processes, which often show low productivity and high production costs compared to chemical processes. To increase the economic competitiveness of biological processes, continuous fermentation technologies are being developed that offer significant advantages in comparison with batch/fed-batch fermentation processes, including: (1) removal of potential substrates and product inhibition, (2) prolonging the microbial exponential growth phase and enhancing productivity, and (3) avoiding repeated fermentation preparation and lowering operation and installation costs. However, several key challenges should be addressed for the industrial application of continuous fermentation processes, including (1) contamination of the fermentation system, (2) degeneration of strains, and (3) relatively low product titer. In this study, we reviewed and discussed metabolic engineering and synthetic biology strategies to address these issues.

关键词： continuous fermentation productivity contamination strain degeneration metabolic engineering

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Ant colony optimization in continuous problem

YU Ling, LIU Kang, LI Kaishi

《机械工程前沿（英文）》 2007年第2卷第4期页码 459-462 doi: 10.1007/s11465-007-0079-6

摘要： Based on the analysis of the basic ant colony optimization and optimum problem in a continuous space, an ant colony optimization (ACO) for continuous problem is constructed and discussed. The algorithm is efficient and beneficial to the study of the ant colony optimization in a continuous space.

关键词： beneficial algorithm efficient continuous ACO

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Inverse uncertainty characteristics of pollution source identification for river chemical spill incidents

Jiping Jiang, Feng Han, Yi Zheng, Nannan Wang, Yixing Yuan

《环境科学与工程前沿（英文）》 2018年第12卷第5期 doi: 10.1007/s11783-018-1081-4

摘要：

Uncertainty rules of pollution source inversion are revealed by stochastic analysis

A release load is most easily inversed and source locations own largest uncertainty

Instantaneous spill assumption has much less uncertainty than continuous spill

The estimated release locations and times negatively deviate from real values

The new findings improve monitoring network design and emergency response to spills

关键词： River chemical spills Emergency response Pollution source inversion Inverse uncertainty analysis Regional Sensitivity Analysis method (RSA) Monte Carlo analysis toolbox (MCAT)

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Source apportionment of ambient PM

Bo HAN, Xiaohui BI, Yonghua XUE, Jianhui WU, Tan ZHU, Baogui ZHANG, Jianqing DING, Yuanxin DU

《环境科学与工程前沿（英文）》 2011年第5卷第4期页码 552-563 doi: 10.1007/s11783-010-0263-5

摘要： A total of 168 PM samples were collected during the year of 2005 at eight sites in the city of Wuxi in China. Fifteen chemical elements, three water-soluble ions, total carbon and organic carbon were analyzed. Six source categories were identified and their contributions to ambient PM in Wuxi were estimated using a nested chemical mass balance method that reduces the effects of colinearity on the chemical mass balance model. In addition, the concentrations of secondary aerosols, such as secondary organic carbon, sulfate and nitrate, were quantified. The spatially averaged PM was high in the spring and winter (123 μg·m and low in the summer–fall (90 μg·m ). According to the result of source apportionment, resuspended dust was the largest contributor to ambient PM , accounting for more than 50% of the PM mass. Coal combustion (14.6%) and vehicle exhaust (9.4%) were also significant source categories of ambient PM . Construction and cement dust, sulfates, secondary organic carbon, and nitrates made contributions ranging between 4.1% and 4.9%. Other source categories such as steel manufacturing dust and soil dust made low contributions to ambient PM .

关键词： source apportionment inhalable particulate matter nested chemical mass balance method

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Quantitative standard of eco-compensation for the water source area in the middle route of the South-to-North

Zhanfeng DONG, Jinnan WANG

《环境科学与工程前沿（英文）》 2011年第5卷第3期页码 459-473 doi: 10.1007/s11783-010-0288-9

摘要： The Middle Route Project(MRP) of the South-to-North Water Transfer Scheme (SNWT) in China will require a very large financial expenditure to ensure the water supply and the associated water quality to northern China. An eco-compensation mechanism between the water service source areas and its beneficiaries is essential. This paper establishes an analytic framework of eco-compensation standard for the protection of the water source area, including both the calculation of eco-compensation based on opportunity cost method (OCM) and calculation of the burden sharing of eco-compensation between the water source area and the external water reception area based on the deviation square method (DSM). Taking Shiyan City, Hubei Province in China as a case study, our results show that the eco-compensation in the first-phase of MRP for the water source area in Shiyan, Hubei Province should be 1.63×10 CNY, about four times of planned eco-construction investment budget(4.33×10 CNY). In addition, the burden sharing of eco-compensation varied greatly in terms of different methods. It would be better to integrate the results of different single-factor burden sharing methods by determining the corresponding weighting coefficient with DSM and form one unanimous consent result by the interested parties.

关键词： the South-to-North Water Transfer Scheme eco-compensation standard opportunity costs deviation square method

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连续铸钢前沿技术的工程化

干勇

《中国工程科学》 2002年第4卷第9期页码 12-18

摘要：

论述了具有我国自主知识产权的高效连铸和薄板坯连铸工程化关键技术的特点；介绍了连续铸钢领域轻压下、液压非正弦振动、电磁连铸等前沿技术的开发现状；阐述了传统连铸技术超高效率、高品质化及近终形连铸、电磁连铸开发的研发方向。

关键词：连续铸钢高效连铸薄板坯连铸轻压下电磁连铸

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标题作者时间类型操作

Computational simulation methods for fiber reinforced composites

Vladimír KOMPI, Zuzana MURINKOV, Sergey RJASANOW, Richards GRZIBOVSKIS, Qinghua QIN,

期刊论文

Independent continuous and mapping method of structural topology optimization based on the global stress

Yunkang SUI, Jili FENG, Hongling YE, Xirong PENG,

期刊论文

A continuous/discontinuous deformation analysis (CDDA) method based on deformable blocks for fracture

Yongchang CAI, Hehua ZHU, Xiaoying ZHUANG

期刊论文

A method for quantifying bias in modeled concentrations and source impacts for secondary particulate

Cesunica E. Ivey, Heather A. Holmes, Yongtao Hu, James A. Mulholland, Armistead G. Russell

期刊论文

城市大气污染源追踪“广义判识”与Nudging源同化集成技术途径

徐祥德,丁国安

期刊论文

大跨度混凝土连续梁桥的病害成因分析

林帆,王萍,肖开军,李伟

期刊论文

A method of determining flame radiation fraction induced by interaction burning of tri-symmetric propanefires in open space based on weighted multi-point source model

Jie JI, Junrui DUAN, Huaxian WAN

期刊论文

颗粒物面源模式计算方法

谷清,杨新兴,李云生

期刊论文

Calculation and analysis of sub/supercritical methanol preheating tube for continuous production of biodiesel

Wen CHEN, Weiyong YING, Cunwen WANG, Weiguo WANG, Yuanxin WU, Junfeng ZHANG,

期刊论文

Strain and process engineering toward continuous industrial fermentation

期刊论文

Ant colony optimization in continuous problem

YU Ling, LIU Kang, LI Kaishi