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Earthquake Engineering and Engineering Vibration 2012年第3期11卷 331-342页

作者： D. Wu s. Tesfamariam s.f. stiemer D. Qin Key Laboratory of Earthquake Engineering and Applied Technique of Guangdong Province Guangzhou 501405 China school of Engineering University of British Columbia Kelowna V1 V 1 V7 Canada Dept. of Civil Engineering University of British Columbia Vancouver V6T 1Z4 Canada Dept. of Civil Engineering Radio Film and Television Design and Research Institute Beijing 100045 China

following several damaging earthquakes in China, research has been devoted to find the causes of the collapse of reinforced concrete （RC） building sand studying the vulnerability of existing buildings. The Chinese Code for seismic Design of Buildings （CCsDB） has evolved over time, however, there is still reported earthquake induced damage of newly designed RC buildings. Thus, to investigate modern Chinese seismic design code, three low-, mid- and high-rise RC frames were designed according to the 2010 CCsDB and the corresponding vulnerability curves were derived by computing a probabilistic seismic demand model （PsDM）.The PsDM was computed by carrying out nonlinear time history analysis using thirty ground motions obtained from the Pacific Earthquake Engineering Research Center. finally, the PsDM was used to generate fragility curves.f.r immediate occupancy, significant damage, and collapse prevention damage levels. Results of the vulnerability assessment indicate that the seismic demands on the three different frames designed according to the 2010 CCsDB meet the seismic requirements and are almost in the same s.f.ty level.

关键词： building damage criteria collapse ratio probabilistic seismic demand model (PsDM) fragility curves Chinese Code for seismic Design of Buildings (CCsDB)

Evaluation of Metal fatigue Problems Using Qualitative Reasoning Approach

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Tsinghua science and Technology 2008年第S1期13卷 96-101页

作者： siegfried f. stiemer Civil Engineering Department University of British Columbia

fatigue failures are often encountered in steel structures under heavy cyclic loadings. This paper presents metal fatigue problems in structural engineering using outcomes of recent advancements in numerical qualitative reasoning. Qualitative reasoning provides an effective and sound technique for solving complex and uncertain scenarios, regardless of the uncertainty or linearity of the design parameters and their constraints. This paper introduces the algorithms behind a s.f.ware platform, built upon numerical qualitative reasoning for engineering applications. The s.f.ware expresses the results of the analysis in variable ranges and diagrams showing a two-dimensional design space. The capability of representing design parameters and outcomes in solution spaces provides a practical way for engineers to leverage their existing knowledge and experience. Case studies in metal fatigue design are given to reflect on the capability of qualitative reasoning in engineering applications.

关键词： computer applications conceptual design decision support system constraints qualitative reasoning fatigue

A sMALLEsT sINGULAR VALUE METHOD fOR sOLVING INVERsE EIGENVALUE PROBLEMs

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Journal of Computational Mathematics 1996年第1期14卷 23-31页

作者： s.f. Xu(Department of Mathematics, Peking University, Beijing) 北京大学数学系北京

Utilizing the properties of the smallest singular value of a matrix, we propose a new, efficient and reliable algorithm for solving nonsymmetric matrix inverse eigenvalue problems, and compare it with a known method. ... 详细信息

关键词： Math A sMALLEsT sINGULAR VALUE METHOD fOR sOLVING INVERsE EIGENVALUE PROBLEMs

RELATIONsHIP BETWEEN J-INTEGRAL AND fRACTURE sURfACE AVERAGE PROfILE

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Acta Metallurgica sinica(English Letters) 2007年第1期20卷 40-48页

作者： Y.G. Cao s.f. Xue K. Tanaka Department of Engineering Mechanics College of Architecture and Transport and Storage Engineering China University of Petroleum Dongying 257061 China Department of Mechanical systems Engineering Toyama Prefectural University Toyama 939-0398 Japan

To investigate the causes that led to the formation of cracks in materials, a novel method that only considered the fracture surfaces.f.r determining the fracture toughness parameters of J-integral for plain strain was proposed The principle of the fracture-surface topography analysis （fRAsTA） was used. In fRAsTA, the fracture surfaces were scanned by laser microscope and the elevation data was recorded for analysis. The relationship between J-integral and fracture surface average profile for plain strain was deduced. It was also verified that the J-integral determined by the novel method and by the compliance method matches each other well.

关键词： fRAsTA (fracture-surface topography analysis) J-integral fracture surface

Merging bound states in the continuum in an open acoustic resonator

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science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 124-131页

作者： Lujun Huang Bin Jia Artem s.Pilipchuk sibo Huang Chen shen Almas.f.sadreev Yong Li Andrey E.Miroshnichenko school of Physics and Electronic sciences East China Normal University Institute of Acoustics Tongji University L.V.Kirensky Institute of Physics Department of Mechanical Engineering Rowan University school of Engineering and Technology University of New South Wales at Canberra

Bound states in the continuum （BICs） are perfectly localized resonances despite embedding in the continuum ***,an isolated BIC is very sensitive to the structure ***,we report merging acoustic BICs in a single open resonator,robust against the structure *** find that both symmetry-protected BIC and friedrich-Wintgen BIC are sustained in a single coupled waveguide-resonator *** varying the height and length of the resonator,these two BICs move toward each other and merge into a single one at a critical *** to an individual BIC,the merged BIC is robust against fabrication error because its Q-factor is proportional to ΔL-4,whereΔL embodies the structure *** essence of this extraordinary phenomenon is perfectly explained by the two-and three-level approximations of the effective nonHermitian ***,we present direct experimental demonstrations of the moving and merging of BICs in a coupled 3D waveguide-resonator,which are evidenced by the vanishing of the linewidth of fano resonance in the transmission *** results may find exciting applications in designing high-quality acoustic sources,sensors and filters.

关键词： acoustic resonances bound state in the continuum high-Q resonances

A Comparative study of Boron and Phosphorus Doping Effects in siC: H films Prepared by ECR-CVD

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Journal of Materials science & Technology 1998年第1期14卷 65-71页

作者： s.f. Yoon (school of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue,singapore 639798, Rep. of singapore) school of Electrical and Electronic Engineering Nanyang Technological University Singapore 639798 Nanyang Avenue Singapore

Hydrogenated silicon carbide films (siC:H) were deposited using the electron cyclotron resonance chemical vapour deposition (ECR-CVD) technique from a mixture of methane, silane and hydrogen, and using diborane and phosphine as doping gases. The effects of changes in the microwave power on the deposition rate and optical bandgap were investigated, and variations in the photoand dark-conductivities and activation energy were studied in conjunction with film analysis using the Raman scattering technique. In the case of boron-doped samples, the conductivity increased rapidly to a maximum, followed by rapid reduction at high microwave power. The ratio of the photo- to dark-conductivity (σph/σd) peaked at microwave power of ~600 W. Under conditions of high microwave power, Raman scattering analysis showed evidence of the formation and increase in the silicon microcrystalline and diamond-like phases in the films, the former of which could account for the rapid increase and the latter the subsequent decrease in the *** the case of phosphorusdoped siC:H samples, it was.f.und that increase in the microwave power has the effect of enhancing the formation of the silicon microcrystalline phase in the films which occurred in correspondence to a rapid increase in the conductivity and reduction in the activation energy The conductivity increase stabilised in samples deposited at microwave power exceeding 500 W probably as a result of dopant saturation. Results.f.om Raman scattering measurements also showed that phosphorus doping had the effect of enhancing the formation of the silicon microcrystals in the film whereas the presence of boron had the effect of preserving the amorphous structure.

关键词： ECR A Comparative study of Boron and Phosphorus Doping Effects in siC H films Prepared by ECR-CVD

Optical and structural Properties of In_(0.52)Al_(0.48)As/InP structures Grown at Very High Arsenic Overpressures by Molecular Beam Epitaxy

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Journal of Materials science & Technology 1998年第3期14卷 231-235页

作者： s.f. Yoon(school of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue,singapore 639798, Rep. of singapore school of Electrical and Electronic Engineering Nanyang Technological University Singapore 639798 Nanyang Avenue Singapore

Growth of ln0.52Al0.48As epitaxial layers on lnP(100) substrates by molecular beam epitaxy at a wide range of arsenic overpressures (V/III flux ratios.f.om 30 to 300) has been carried out. Analysis performed using low-temperature photoluminescence (PL) and double-axis X-ray diffraction (XRD) shows a strong and prominent dependence of the PL and XRD linewidths on the V/III flux ratio. Under our growth conditions, both the PL and XRD linewidths exhibit a minimum point at a V/III flux ratio of 150 which corresponds to a maximum in the PL intensity and XRD intensity ratio. flux ratios exceeding 150 result in an increase in both the PL and XRD linewidths corresponding to a reduction in their associated intensities. Room temperature Raman scattering measurements show a narrowing in the lnAs-like and AlAs-like longitudinal-optic (LO)phonon linewidths which broaden at high flux ratios, while the LO phonon frequencies exhibit a gradual reduction as the flux ratio is increased. PL spectra taken at increasing temperatures show a quenching of the main emission peak followed by the evolution of a broad lower energy emission which is possibly associated with deep lying centres. This effect is more prominent in samples grown at lower V/III flux ratios. Hall effect measurements show a gradual reduction in the mobility in correspondence to an increase in the electron concentration as the flux ratio is increased.

关键词： As/InP structures Grown at Very High Arsenic Overpressures by Molecular Beam Epitaxy InP Optical and structural Properties of In Al

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高原高寒地区H形混凝土桥塔日照温度效应

交通运输工程学报 2017年第4期17卷 66-77页

作者：张宁刘永健刘江季德钧房建宏 stiemer s f 西北农林科技大学水利与建筑工程学院陕西杨凌712100 长安大学公路学院陕西西安710064 青海省高等级公路建设管理局青海西宁810008 青海省交通科学研究院青藏高原公路建设与养护重点实验室青海西宁810008 不列颠哥伦比亚大学土木工程系

分析了混凝土结构温度场边界条件计算方法,以青海省海黄大桥H形混凝土桥塔为工程背景,计算了高原高寒地区四季典型气象条件下的桥塔温度场分布,对比了四季的桥塔表面温差和塔壁局部温差,确定了桥塔的最不利温度荷载,建立了桥塔整体有限... 详细信息

分析了混凝土结构温度场边界条件计算方法,以青海省海黄大桥H形混凝土桥塔为工程背景,计算了高原高寒地区四季典型气象条件下的桥塔温度场分布,对比了四季的桥塔表面温差和塔壁局部温差,确定了桥塔的最不利温度荷载,建立了桥塔整体有限元模型,分析了四季桥塔的偏位、竖向应力、横向应力和纵向应力等温度效应。分析结果表明:桥塔表面温差与桥塔局部温差均在冬季最大,最大值分别可达11.88℃、20.79℃,在夏季最小,最大值分别可达5.15℃、15.25℃;横桥向和纵桥向桥塔表面温差最大值分别达到9.15℃、11.88℃,远大于《公路斜拉桥设计细则》(JTG/T D65-01—2007)推荐值±5℃;接近正南方向的塔壁局部温差最大,沿壁厚方向的温差分布接近指数形式,冬季和夏季温度衰减系数最大值分别为4.50、5.01,故冬季桥塔壁板局部温度分布较夏季更不均匀;桥塔温度效应同样在冬季最大,1天中最大桥塔偏位超过40mm,白天桥塔偏位变化值超过15mm,不利于施工过程中的桥塔偏位监测;桥塔根部竖向最大拉应力达到2.2MPa,桥塔根部同样产生较大水平向拉应力,纵桥向和横桥向最大拉应力分别为1.82、0.82 MPa,均发生在桥塔内侧,在与其他作用组合时可能会造成桥塔开裂,建议在桥塔塔壁内侧布置一定量的钢筋网片来控制裂缝;在进行高原高寒地区桥塔设计和施工控制时,应充分考虑温度效应带来的不利影响。

关键词：桥梁工程混凝土桥塔高原高寒地区有限元模型温度分布温度效应混凝土开裂

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地震灾区既有混凝土框架结构的抗震性能研究

建筑科学与工程学报 2013年第2期30卷 42-48页

作者：吴迪谭平 stiemer s f 广州大学广东省地震工程与应用技术重点实验室广东广州510405 不列颠哥伦比亚大学土木工程系

以汶川县威州镇一幢既有典型混凝土框架结构房屋为研究对象,分析了当地现有混凝土结构的抗震安全水平。采用《建筑抗震设计规范》(GB 50011—2010)设定的设防烈度及地震水平,对混凝土结构进行非线性时程分析,建立了该结构的概率地震需... 详细信息

以汶川县威州镇一幢既有典型混凝土框架结构房屋为研究对象,分析了当地现有混凝土结构的抗震安全水平。采用《建筑抗震设计规范》(GB 50011—2010)设定的设防烈度及地震水平,对混凝土结构进行非线性时程分析,建立了该结构的概率地震需求模型。依据该模型确定结构地震易损性水平,建立继续使用、严重破坏和倒塌3种状态下结构的地震易损性曲线,以此研究汶川县此类结构设计的抗震安全水平。研究结果表明:此类既有混凝土框架结构不能完全满足《建筑抗震设计规范》(GB 50011—2010)中不同抗震设防等级关于房屋破坏和倒塌的基本要求。

关键词：抗震性能概率地震需求模型地震易损性分析混凝土框架结构

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交叉层积木数值模拟研究以及连接损伤分析

工程科学学报 2016年第1期38卷 149-157页

作者：沈银澜牟在根 Johannes schneider siegfried f.stiemer 北京科技大学土木与环境工程学院北京100083 中国电子工程设计院北京100142 英属哥伦比亚大学应用学院土木工程系

木建筑由于结构冗余性以及钉接节点超强的吸能耗能能力在抗震中表现良好.交叉层积木是一种新型的建筑材料.本文以交叉层积木3种柔性连接试验为基础,采用Open sees中Pinching4自定义模型模拟连接滞回曲线的高度非线性、强度退化、刚度退... 详细信息

木建筑由于结构冗余性以及钉接节点超强的吸能耗能能力在抗震中表现良好.交叉层积木是一种新型的建筑材料.本文以交叉层积木3种柔性连接试验为基础,采用Open sees中Pinching4自定义模型模拟连接滞回曲线的高度非线性、强度退化、刚度退化和捏拢现象.基于主次半循环累积能量的损伤模型,对交叉层积木连接进行损伤分析,并提出该连接的5种性能水平的损伤指数.Pinching4模型与连接试验结果吻合较好,进一步证明该模型模拟木节点连接性能的可行性和有效性.损伤因子对应的损伤程度基本符合试验规律,其平均值在合理范围内,计算结果离散性较低.

关键词：交叉层积木结构连接数值研究损伤分析损伤累积模型