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Finite element simulation for elastic dislocation of the North-Tehran fault: The effects of geologic

Pooya ZAKIAN; Hossein ASADI HAYEH

《结构与土木工程前沿（英文）》 2022年第16卷第4期页码 533-549 doi: 10.1007/s11709-022-0802-8

摘要： The present study uses the finite element method for simulating the crustal deformation due to the dislocation of a segment of the North-Tehran fault located in the Karaj metropolis region. In this regard, a geological map of Karaj that includes the fault segment is utilized in order to create the geometry of finite element model. First, finite element analysis of homogeneous counterpart of the fault’s domain with two different sections was performed, and the results were compared to those of Okada’s analytical solutions. The fault was modeled with the existing heterogeneity of the domain having been considered. The influences of both uniform and non-uniform slip distributions were investigated. Furthermore, three levels of simplification for geometric creation of geological layers’ boundaries were defined in order to evaluate the effects of the geometric complexity of the geological layering on the displacement responses obtained with the finite element simulations. In addition to the assessment of slip distribution, layering complexity and heterogeneity, the results demonstrate both the capability and usefulness of the proposed models in the dislocation analysis for the Karaj segment of North-Tehran fault.

关键词： finite element method fault dislocation slip distribution the North-Tehran fault heterogeneity geological layering

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An end-to-end 3d seismic simulation of underground structures due to point dislocation source by using

Zhenning BA; Jisai FU; Zhihui ZHU; Hao ZHONG

《结构与土木工程前沿（英文）》 2022年第16卷第12期页码 1515-1529 doi: 10.1007/s11709-022-0887-0

摘要： Based on the domain reduction idea and artificial boundary substructure method, this paper proposes an FK-FEM hybrid approach by integrating the advantages of FK and FEM (i.e., FK can efficiently generate high-frequency three translational motion, while FEM has rich elements types and constitutive models). An advantage of this approach is that it realizes the entire process simulation from point dislocation source to underground structure. Compared with the plane wave field input method, the FK-FEM hybrid approach can reflect the spatial variability of seismic motion and the influence of source and propagation path. This approach can provide an effective solution for seismic analysis of underground structures under scenario of earthquake in regions where strong earthquakes may occur but are not recorded, especially when active faults, crustal, and soil parameters are available. Taking Daikai subway station as an example, the seismic response of the underground structure is simulated after verifying the correctness of the approach and the effects of crustal velocity structure and source parameters on the seismic response of Daikai station are discussed. In this example, the influence of velocity structure on the maximum interlayer displacement angle of underground structure is 96.5% and the change of source parameters can lead to the change of structural failure direction.

关键词： source-to-structure simulation FK-FEM hybrid approach underground structures point dislocation source

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Adaptive simulation of wave propagation problems including dislocation sources and random media

Hassan YOUSEFI, Jamshid FARJOODI, Iradj MAHMOUDZADEH KANI

《结构与土木工程前沿（英文）》 2019年第13卷第5期页码 1054-1081 doi: 10.1007/s11709-019-0536-4

摘要： An adaptive Tikhonov regularization is integrated with an h-adaptive grid-based scheme for simulation of elastodynamic problems, involving seismic sources with discontinuous solutions and random media. The Tikhonov method is adapted by a newly-proposed detector based on the MINMOD limiters and the grids are adapted by the multiresolution analysis (MRA) via interpolation wavelets. Hence, both small and large magnitude physical waves are preserved by the adaptive estimations on non-uniform grids. Due to developing of non-dissipative spurious oscillations, numerical stability is guaranteed by the Tikhonov regularization acting as a post-processor on irregular grids. To preserve waves of small magnitudes, an adaptive regularization is utilized: using of smaller amount of smoothing for small magnitude waves. This adaptive smoothing guarantees also solution stability without over smoothing phenomenon in stochastic media. Proper distinguishing between noise and small physical waves are challenging due to existence of spurious oscillations in numerical simulations. This identification is performed in this study by the MINMOD limiter based algorithm. Finally, efficiency of the proposed concept is verified by: 1) three benchmarks of one-dimensional (1-D) wave propagation problems; 2) P-SV point sources and rupturing line-source including a bounded fault zone with stochastic material properties.

关键词： adaptive wavelet adaptive smoothing discontinuous solutions stochastic media spurious oscillations Tikhonov regularization minmod limiter

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软硬不均地层盾构姿态控制及管片防裂损技术

谭忠盛,洪开荣,万姜林,王梦恕

《中国工程科学》 2006年第8卷第12期页码 92-96

摘要：

广州地铁二号线越—三盾构区间的地层软硬不均，加之曲线多、坡度变化大，盾构掘进技术难度大，掘进方向与盾构姿态的控制困难，防止管片开裂和局部破损以及错台具有一定的难度。为了有效地控制掘进方向和盾构姿态，研究了盾构掘进方向发生偏差的原因，并对越—三区间盾构掘进的偏差实测数据进行具体分析，得出了偏差的原因和规律；研究了盾构掘进姿态的控制方法。为了防止盾构管片的裂损，采用数值模拟方法研究管片裂损的规律及其主要因素，提出了有效控制管片裂损的主要方法。

关键词：软硬不均地层盾构姿态控制管片裂损管片错台

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Defect passivation on cast-mono crystalline screen-printed cells

Alison WENHAM,Lihui SONG,Malcolm ABBOTT,Iskra ZAFIROVSKA,Sisi WANG,Brett HALLAM,Catherine CHAN,Allen BARNETT,Stuart WENHAM

《能源前沿（英文）》 2017年第11卷第1期页码 60-66 doi: 10.1007/s11708-016-0443-5

摘要： Cast-mono crystalline silicon wafers contain crystallographic defects, which can severely impact the electrical performance of solar cells. This paper demonstrates that applying hydrogenation processes at moderate temperatures to finished screen print cells can passivate dislocation clusters within the cast-mono crystalline silicon wafers far better than the hydrogenation received during standard commercial firing conditions. Efficiency enhancements of up to 2% absolute are demonstrated on wafers with high dislocation densities. The impact of illumination to manipulate the charge state of hydrogen during annealing is investigated and found to not be significant on the wafers used in this study. This finding is contrary to a previous study on similar wafers that concluded increased H or H from laser illumination was responsible for the further passivation of positively charged dangling bonds within the dislocation clusters.

关键词： silicon solar cell dislocation cast-mono laser hydrogen passivation

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用于制造高效低成本太阳能电池的单晶种铸造大型单晶硅 Article

Bing Gao,Satoshi Nakano,Hirofumi Harada,Yoshiji Miyamura,Takashi Sekiguchi,Koichi Kakimoto

《工程（英文）》 2015年第1卷第3期页码 378-383 doi: 10.15302/J-ENG-2015032

摘要：

为了能以低成本生产优质大型单晶硅，笔者提出了单晶种铸造技术。这项技术的实施，必须解决两个问题，即坩埚壁上的多晶成核问题和晶体内的位错增殖问题。在本文中，笔者尝试通过数值分析法来解决这两个问题。根据数值分析得出的优化熔炉结构和工况进行了实验，在实验中采用单晶种铸造技术来生长单晶硅。实验结果表明，该技术远优于常用的高性能多晶和准单晶铸造技术。

关键词：单晶种铸造单晶硅多晶成核位错增殖多晶硅