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SINOPEC's Success in Fixed-bed Methanol-to-Propylene Pilot Scale Tests
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《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2014年第3期9-9,共1页
The first in China pilot tests of fixed-bed methanol-topropylene unit were successfully implemented at the Yangzi Petrochemical Company(YPC).It is told that this technology has opened up a new process for production o... The first in China pilot tests of fixed-bed methanol-topropylene unit were successfully implemented at the Yangzi Petrochemical Company(YPC).It is told that this technology has opened up a new process for production of propylene through coal gasification,and China has possessed both the fluidized-bed methanolto-propylene process(F-MTP)and the 展开更多
关键词 MTP SINOPEC’s Success in Fixed-bed Methanol-to-Propylene Pilot scale tests
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The Preliminary Study on the Small-scale Test of the Microbial Quick-degumming Ramie
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作者 吴瑜 《武汉科技学院学报》 2008年第4期1-4,共4页
During the experiments with low temperature plasma treating the ramie degumming microbe,the authors found some kinds of microbe which can degum ramie in 5-6L fluid very quickly.In comparison with some standards of mic... During the experiments with low temperature plasma treating the ramie degumming microbe,the authors found some kinds of microbe which can degum ramie in 5-6L fluid very quickly.In comparison with some standards of microbiological experiments,5L or 6L-scale can be called the small-scale.Therefore,the authors believe that the experiments of the microbial quick-degumming ramie can be enlarged from the laboratory-scale test to be applied in the future. 展开更多
关键词 苎麻 厌氧微生物 脱胶 生物技术
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3-D Modelling of the Confederation Bridge Using Data of Full Scale Tests
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作者 Lan Lin 《Open Journal of Civil Engineering》 2013年第3期18-25,共8页
Long-span bridges are special structures that require advanced analysis techniques to examine their performance. This paper presents a procedure developed to model the Confederation Bridge using 3-D beam elements. The... Long-span bridges are special structures that require advanced analysis techniques to examine their performance. This paper presents a procedure developed to model the Confederation Bridge using 3-D beam elements. The model was validated using the data collected before the opening of the bridge to the public. The bridge was instrumented to conduct fullscale static and dynamic tests. The static tests were to measure the deflection of the bridge pier while the dynamic tests to measure the free vibrations of the pier due to a sudden release of the static load. Confederation Bridge is one of the longest reinforced concrete bridges in the world. It connects the province of Prince Edward Island and the province of New Brunswick in Canada. Due to its strategic location and vital role as a transportation link between these two provinces, it was designed using higher safety factors than those for typical highway bridges. After validating the present numerical model, a procedure was developed to evaluate the performance of similar bridges subjected to traffic and seismic loads. It is of interest to note that the foundation stiffness and the modulus of elasticity of the concrete have significant effects on the structural responses of the Confederation Bridge. 展开更多
关键词 3-D Numerical Modeling Finite Element Technique Static testS Dynamic testS ACCELERATION Time HISTORY FOURIER Analysis Full scale test SEISMIC Evaluation Confederation BRIDGE
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Small-scale fire tests in the underwater tunnel section model with new sidewall smoke extraction
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作者 Shunyu Yue Ruifeng Miao +2 位作者 Huihang Cheng Maohua Zhong Xiujun Yang 《Deep Underground Science and Engineering》 2024年第2期247-254,共8页
The Shenzhen–Zhongshan Bridge is a 24‐km‐long bridge and tunnel system,including a 6.8-km-long super cross section subsea tunnel.To solve the smoke exhaust problem of a super large cross-section subsea tunnel,the t... The Shenzhen–Zhongshan Bridge is a 24‐km‐long bridge and tunnel system,including a 6.8-km-long super cross section subsea tunnel.To solve the smoke exhaust problem of a super large cross-section subsea tunnel,the tunnel has a new smoke exhaust system that combines a horizontal smoke exhaust cross section at the top and sidewall smoke exhaust holes.In order to evaluate the potential fire hazards of this type of tunnel,a 1:30 tunnel model was established and 140 smallscale experiments on underwater tunnel fires were conducted.By changing the fire power,fire location,and fan operation mode,different scenarios of submarine immersed tunnel fire were simulated and the related key parameters such as fire smoke diffusion behavior and smoke temperature distribution were studied.On this basis,the optimal smoke control strategy was proposed for different fire scenarios.The research results indicate that the new smoke exhaust system can fully utilize the smoke flow characteristics,significantly improve smoke exhaust efficiency,and increase available evacuation time,thus further enhancing the fire safety of super large cross-section subsea tunnels. 展开更多
关键词 sidewall smoke extraction system small‐scale fire tests smoke control
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Research on the intelligent internet nursing model based on the child respiratory and asthma control test scale for asthma management of preschool children
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作者 Chuan-Feng Pei Li Zhang +2 位作者 Xi-Yan Xu Zhen Qin Hong-Mei Liang 《World Journal of Clinical Cases》 SCIE 2023年第28期6707-6714,共8页
BACKGROUND Childhood asthma is a common respiratory ailment that significantly affects preschool children.Effective asthma management in this population is particularly challenging due to limited communication skills ... BACKGROUND Childhood asthma is a common respiratory ailment that significantly affects preschool children.Effective asthma management in this population is particularly challenging due to limited communication skills in children and the necessity for consistent involvement of a caregiver.With the rise of digital healthcare and the need for innovative interventions,Internet-based models can potentially offer relatively more efficient and patient-tailored care,especially in children.AIM To explore the impact of an intelligent Internet care model based on the child respiratory and asthma control test(TRACK)on asthma management in preschool children.METHODS The study group comprised preschoolers,aged 5 years or younger,that visited the hospital's pediatric outpatient and emergency departments between January 2021 and January 2022.Total of 200 children were evenly and randomly divided into the observation and control groups.The control group received standard treatment in accordance with the 2016 Guidelines for Pediatric Bronchial Asthma and the Global Initiative on Asthma.In addition to above treatment,the observation group was introduced to an intelligent internet nursing model,emphasizing the TRACK scale.Key measures monitored over a six-month period included the frequency of asthma attack,emergency visits,pulmonary function parameters(FEV1,FEV1/FVC,and PEF),monthly TRACK scores,and the SF-12 quality of life assessment.Post-intervention asthma control rates were assessed at six-month follow-up.RESULTS The observation group had fewer asthma attacks and emergency room visits than the control group(P<0.05).After six months of treatment,the children in both groups had higher FEV1,FEV1/FVC,and PEF(P<0.05).Statistically significant differences were observed between the two groups(P<0.05).For six months,children in the observation group had a higher monthly TRACK score than those in the control group(P<0.05).The PCS and MCSSF-12 quality of life scores were relatively higher than those before the nursing period(P<0.05).Furthermore,the groups showed statistically significant differences(P<0.05).The asthma control rate was higher in the observation group than in the control group(P<0.05).CONCLUSION TRACK based Intelligent Internet nursing model may reduce asthma attacks and emergency visits in asthmatic children,improve lung function,quality of life,and the TRACK score and asthma control rate.The effect of nursing was significant,allowing for development of an asthma management model. 展开更多
关键词 Child respiratory and asthma control test scale Intelligent internet nursing model PRESCHOOLERS Childhood asthma Administration Healthcare
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Acoustic emission characterization of microcracking in laboratory-scale hydraulic fracturing tests 被引量:9
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作者 Jesse Hampton Marte Gutierrez +2 位作者 Luis Matzar Dandan Hu Luke Frash 《Journal of Rock Mechanics and Geotechnical Engineering》 CSCD 2018年第5期805-817,共13页
Understanding microcracking near coalesced fracture generation is critically important for hydrocarbon and geothermal reservoir characterization as well as damage evaluation in civil engineering structures. Dense and ... Understanding microcracking near coalesced fracture generation is critically important for hydrocarbon and geothermal reservoir characterization as well as damage evaluation in civil engineering structures. Dense and sometimes random microcracking near coalesced fracture formation alters the mechanical properties of the nearby virgin material. Individual microcrack characterization is also significant in quantifying the material changes near the fracture faces (i.e. damage). Acoustic emission (AE) monitoring and analysis provide unique information regarding the microcracking process temporally, and infor- mation concerning the source characterization of individual microcracks can be extracted. In this context, laboratory hydraulic fracture tests were carried out while monitoring the AEs from several piezoelectric transducers. In-depth post-processing of the AE event data was performed for the purpose of under- standing the individual source mechanisms. Several source characterization techniques including moment tensor inversion, event parametric analysis, and volumetric deformation analysis were adopted. Post-test fracture characterization through coring, slicing and micro-computed tomographic imaging was performed to determine the coalesced fracture location and structure. Distinct differences in fracture characteristics were found spatially in relation to the openhole injection interval. Individual microcrack AE analysis showed substantial energy reduction emanating spatially from the injection interval. It was quantitatively observed that the recorded AE signals provided sufficient information to generalize the damage radiating spatially away from the injection wellbore. 展开更多
关键词 Acoustic emission (AE) Microcracking Hydraulic fracturing Laboratory-scale testing Moment tensor analysis Fracture coalescence Computed tomography (CT) imaging
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Real-time multibody modeling and simulation of a scaled bogie test rig 被引量:3
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作者 Sundar Shrestha Maksym Spiryagin Qing Wu 《Railway Engineering Science》 2020年第2期146-159,共14页
In wheel–rail adhesion studies,most of the test rigs used are simplified designs such as a single wheel or wheelset,but the results may not be accurate.Alternatively,representing the complex system by using a full ve... In wheel–rail adhesion studies,most of the test rigs used are simplified designs such as a single wheel or wheelset,but the results may not be accurate.Alternatively,representing the complex system by using a full vehicle model provides accurate results but may incur complexity in design.To trade off accuracy over complexity,a bogie model can be the optimum selection.Furthermore,only a real-time model can replicate its physical counterpart in the time domain.Developing such a model requires broad expertise and appropriate software and hardware.A few published works are available which deal with real-time modeling.However,the influence of the control system has not been included in those works.To address these issues,a real-time scaled bogie test rig including the control system is essential.Therefore,a 1:4 scaled bogie roller rig is developed to study the adhesion between wheel and roller contact.To compare the performances obtained from the scaled bogie test rig and to expand the test applications,a numerical simulation model of that scaled bogie test rig is developed using Gensys multibody software.This model is the complete model of the test rig which delivers more precise results.To exactly represent the physical counterpart system in the time domain,a real-time scaled bogie test rig(RT-SBTR)is developed after four consecutive stages.Then,to simulate the RT-SBTR to solve the internal state equations and functions representing the physical counterpart system in rigs used are simplified designs such as a single wheel or wheelset,but the results may not be accurate.Alternatively,representing the complex system by using a full vehicle model provides accurate results but may incur complexity in design.To trade off accuracy over complexity,a bogie model can be the optimum selection.Furthermore,only a real-time model can replicate its physical counterpart in the time domain.Developing such a model requires broad expertise and appropriate software and hardware.A few published works are available which deal with real-time modeling.However,the influence of the control system has not been included in those works.To address these issues,a real-time scaled bogie test rig including the control system is essential.Therefore,a 1:4 scaled bogie roller rig is developed to study the adhesion between wheel and roller contact.To compare the performances obtained from the scaled bogie test rig and to expand the test applications,a numerical simulation model of that scaled bogie test rig is developed using Gensys multibody software.This model is the complete model of the test rig which delivers more precise results.To exactly represent the physical counterpart system in the time domain,a real-time scaled bogie test rig(RT-SBTR)is developed after four consecutive stages.Then,to simulate the RT-SBTR to solve the internal state equations and functions representing the physical counterpart system in equal or less than actual time,the real-time simulation environment is prepared in two stages.To such end,the computational time improved from 4 times slower than real time to 2 times faster than real time.Finally,the real-time scaled bogie model is also incorporated with the braking control system which slightly reduces the computational performances without affecting real-time capability. 展开更多
关键词 Bogie modeling scaled bogie test rig Realtime simulation Wheel-rail adhesion Software in loop
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Simulation of large-scale numerical substructure in real-time dynamic hybrid testing 被引量:7
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作者 Zhu Fei Wang Jinting +2 位作者 Jin Feng Zhou Mengxia Gui Yao 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2014年第4期599-609,共11页
A solution scheme is proposed in this paper for an existing RTDHT system to simulate large-scale finite element (FE) numerical substructures. The analysis of the FE numerical substructure is split into response anal... A solution scheme is proposed in this paper for an existing RTDHT system to simulate large-scale finite element (FE) numerical substructures. The analysis of the FE numerical substructure is split into response analysis and signal generation tasks, and executed in two different target computers in real-time. One target computer implements the response analysis task, wherein a large time-step is used to solve the FE substructure, and another target computer implements the signal generation task, wherein an interpolation program is used to generate control signals in a small time-step to meet the input demand of the controller. By using this strategy, the scale of the FE numerical substructure simulation may be increased significantly. The proposed scheme is initially verified by two FE numerical substructure models with 98 and 1240 degrees of freedom (DOFs). Thereafter, RTDHTs of a single frame-foundation structure are implemented where the foundation, considered as the numerical substructure, is simulated by the FE model with 1240 DOFs. Good agreements between the results of the RTDHT and those from the FE analysis in ABAQUS are obtained. 展开更多
关键词 real-time dynamic hybrid testing large-scale numerical substructure control signal generation finite element simulation
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Digital Simulation of Full Scale Static Test of Aircraft 被引量:11
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作者 许泽 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2005年第2期138-141,共4页
Full scale aircraft static test is a very important process of aircraft design, it is costly and time consuming. The testing accuracy and validity mainly depend on the rationality of the test scheme design. When the a... Full scale aircraft static test is a very important process of aircraft design, it is costly and time consuming. The testing accuracy and validity mainly depend on the rationality of the test scheme design. When the aircraft is being tested, the specimen's safety mainly depends on monitoring and understanding the testing data by way of evaluating the coherence with the digital simulation data synchyononsly. The test digital simulation can aid realizing above requirements and improving the test efficiency significantly during test scheme design stage or testing stage respectively. The key technologies and the solving methods of test digital simulation are presented and the application example is given. 展开更多
关键词 the mechanics of flight vehicle aircraft structure static test digital simulation full scale
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RCS SCALE-MODEL-TESTING METHOD BY VARIANCE IN THE SIZE FOR SIMPLY SHAPED SCATTERERS
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作者 刘宏伟 时振栋 唐璞 《Journal of Electronics(China)》 1995年第2期177-180,共4页
t According to a general representation of physical scale factor of RCS for variance in the size of simply shaped scatterers, a novel RCS model-testing method is described. The computed results of the prototype scatte... t According to a general representation of physical scale factor of RCS for variance in the size of simply shaped scatterers, a novel RCS model-testing method is described. The computed results of the prototype scatterers by this method from the model-testing agree well with their measured values both for two kinds of simply shaped scatterers, cylinders and ladder-shaped plates. 展开更多
关键词 Radar-cross-section(RCS) Model-testing scale factor Physical-optic approximation
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时速120 km地铁快线空气动力学试验研究 被引量:1
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作者 陈勇 李杨 +1 位作者 左建勇 梁习锋 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2024年第3期1156-1167,共12页
为探明设计时速120 km快速地铁列车在多区段桥隧衔接线路运行时的气动效应和气密性能,采用实车试验的方法,在武汉某多区段桥隧衔接地铁快线对某4车编组的新研A型密封性地铁列车开展空气动力学测试。实验测试系统采用LL-250-15A型Kulite... 为探明设计时速120 km快速地铁列车在多区段桥隧衔接线路运行时的气动效应和气密性能,采用实车试验的方法,在武汉某多区段桥隧衔接地铁快线对某4车编组的新研A型密封性地铁列车开展空气动力学测试。实验测试系统采用LL-250-15A型Kulite压力传感器,通过测量列车外部和内部的瞬态压力变化,分析全线路车外压力波动特性,对比沿列车长度方向不同测点位置的压力变化幅值,并分析不同空调状态下的车内压力舒适性。经过3次实验测试分析,该实验的结果具有可重复性。研究结果表明:全线路运行时,列车在隧道段内加减速导致车外压力变化幅值明显大于高架段,气动效应最恶劣的位置为地下段人防门变截面处,列车上行通过该处时车外任意3 s内压力变化幅值为1 071 Pa,下行通过该处时车外任意3 s内压力变化幅值为905 Pa;相对于下行线全线路,上行线车外任意3 s内压力变化幅值大18.3%;列车正线运营时压力波保护阀会在压力变化剧烈区段进行动作响应,列车上行时,空调开启、压力波保护阀正常启用状态下,车内任意3 s内压力变化幅值相对于压力波保护阀打开未启用时减少了16%,下行时,减少了28%,空调压力波保护阀能够有效降低车外压力波动对车内气压变化的影响。本文研究成果可为快速地铁线路设计、地铁列车运营及地铁气密性优化提供参考依据。 展开更多
关键词 地铁快线 桥隧衔接 实车试验 压力波 气密性
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荒漠草原不同植物群落蒸散组分特征及其环境因子影响分析 被引量:2
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作者 陈林 杨新国 +3 位作者 王磊 宋乃平 郑松 吴梦瑶 《生态学报》 CAS CSCD 北大核心 2024年第1期330-342,共13页
蒸散发是生态水文过程的关键环节,掌握蒸散组分的变化特征及其影响因子,对干旱半干旱地区的可持续发展至关重要。以荒漠草原多年生植物针茅群落和一年生植物猪毛蒿群落为研究对象,利用小型蒸渗仪开展了连续3年监测,分析了蒸散组分的日... 蒸散发是生态水文过程的关键环节,掌握蒸散组分的变化特征及其影响因子,对干旱半干旱地区的可持续发展至关重要。以荒漠草原多年生植物针茅群落和一年生植物猪毛蒿群落为研究对象,利用小型蒸渗仪开展了连续3年监测,分析了蒸散组分的日、月和年变化规律,探讨了影响蒸散组分的主要环境因子。结果表明:晴天时,多年生和一年生植物群落蒸散组分呈先增加后减小的抛物线型,夜间蒸散活动较弱,累积蒸散量较低,不足全天总累积蒸散量的20%;阴天时各蒸散组分无明显峰值,且日累积量均较小,一年生和多年生植物群落的蒸散量、蒸发量和蒸腾量无显著差异;10.64 mm/d及以上降雨对蒸散和蒸发的日变化具有明显影响,随着降雨量的增多,蒸散量和蒸发量也呈增大趋势,但蒸腾量则相对较小。从月动态来看,7—9月占全年蒸散量和蒸发量的一半左右,冬春季蒸散量和蒸发量维持在全年最低水平。年蒸散量与年降雨量接近,而蒸腾量占蒸散量的比例低于10%。总体来看,多年生植物群落蒸散量较一年生植物群落多。采用Mantel检验方法分析不同时间尺度影响蒸散组分的主要气候因素,在小时尺度上太阳辐射与蒸发量和蒸腾量显著性水平较高(P<0.01),但相关性较低(r<0.2);在日尺度上,蒸散量、蒸发量和蒸腾量与降雨量的显著性(P<0.01)和相关性(r≥0.4)均最高;而月尺度上,降雨量和降雨速率与蒸散量、蒸发量的相关性较高(0.2≤r<0.4),但显著性较低(P≥0.05)。因此,蒸散组分受环境因子的影响在不同时间尺度上具有较大差异,说明蒸散组分受多种因子共同影响。 展开更多
关键词 荒漠草原 蒸散组分 时间尺度 环境因子 Mantel检验
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平钢板-UHPC组合桥面板纵向抗负弯性能试验研究 被引量:1
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作者 李传习 肖和育 +3 位作者 贺龙飞 施宇 冯浩轩 裴必达 《工程力学》 EI CSCD 北大核心 2024年第3期91-105,共15页
某大桥次边跨及中跨主梁为钢-UHPC组合梁,钢-UHPC组合梁的桥面板首次采用一种通过PBL剪力键将8 mm平钢板与15 cm的UHPC层连接起来的新型组合桥面体系。为了探究该桥新型钢-UHPC组合桥面板抗负弯矩性能与安全性,完成了2块足尺模型的静力... 某大桥次边跨及中跨主梁为钢-UHPC组合梁,钢-UHPC组合梁的桥面板首次采用一种通过PBL剪力键将8 mm平钢板与15 cm的UHPC层连接起来的新型组合桥面体系。为了探究该桥新型钢-UHPC组合桥面板抗负弯矩性能与安全性,完成了2块足尺模型的静力性能试验,进行了桥梁整体受力和桥面板局部受力计算,以及桥面板抗负弯矩极限承载力构成分析。结果表明:UHPC名义开裂强度达8.90 MPa以上,其值远大于实桥荷载作用下UHPC层上缘的纵桥向最大拉应力,组合桥面板负弯矩抗裂性能良好,能满足工程需求;组合桥面板抗负弯承载力的计算,UHPC受拉本构宜采用三折线模型,抗负弯承载力简化计算的UHPC受拉区等效均布应力折减系数可取0.76,抗负弯承载力状态的受压钢板受力仍处于线弹性阶段,抗负弯破坏模式与抗正弯明显不同,为受拉钢筋拉断;PBL剪力键能保证了钢板与UHPC板整体共同受力;组合桥面板在负弯矩作用下的延性良好,裂宽增长缓慢,UHPC的名义极限强度达名义开裂强度的4.1倍以上,到达极限荷载后,组合板承载力没有明显下降。 展开更多
关键词 平钢板-UHPC组合桥面板 纵向受弯 有限元 足尺模型试验 界面滑移 UHPC特征强度 极限承载力构成
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砂土-混凝土接触面剪切带细观变形特征的试验研究 被引量:1
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作者 杨奇 吴亚飞 +3 位作者 陈琛 邓煜晨 徐方 阮波 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2024年第2期613-625,共13页
接触面剪切带的细观变形特征是研究结构物与土体相互作用的核心问题。为探明砂土-混凝土接触面剪切带变形特征,利用大型直剪仪开展砂土-混凝土接触面直剪试验,采用灌砂变形标记法实测砂土变形,依据标记线剪应变沿竖向的变化特征对砂土... 接触面剪切带的细观变形特征是研究结构物与土体相互作用的核心问题。为探明砂土-混凝土接触面剪切带变形特征,利用大型直剪仪开展砂土-混凝土接触面直剪试验,采用灌砂变形标记法实测砂土变形,依据标记线剪应变沿竖向的变化特征对砂土变形区域进行划分。在此基础上,研究粗糙度、法向应力和密实度对砂土-混凝土接触面剪切带细观变形特征的影响规律。研究结果表明:1)砂土可分为非剪切区、过渡区和应变集中区,应变集中区仅存在剪切面之上。2)规则型接触面的上剪切带厚度均值为33D_(50),远大于下剪切带9D_(50)和“光滑”接触面剪切带厚度20.4D_(50)。3)密实度对剪切带及其过渡区厚度的影响微弱,而粗糙度对其影响显著;法向应力、密实度对应变集中区厚度影响有限,应变集中区厚度随粗糙度的增大近似线性增大;应变集中区长度随粗糙度的增大先增大后减小,随密实度的增大近似线性增大,随法向应力增大而减小。4)随剪切位移增大,上剪切带厚度不断增大而下剪切带厚度先增大后保持基本不变,应变集中区的长度增大,但剪切位移对应变集中区厚度的影响有限。5)获得归一化剪切带厚度取值h_(t)/D_(50)与D_(50)的关系,在有限元模拟规则型结构与砂土的相互作用时,建议砂土体细化网格单元的范围不小于最大剪切带厚度37D_(50)。研究成果深化了砂土-规则型接触面剪切带变形特征的认识,可为大粗糙度、带肋桩的承载变形特性的精细化有限元模拟分析提供重要参考和依据。 展开更多
关键词 砂土-混凝土接触面 大型直剪试验 灌砂标记法 剪切带 细观变形
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常泰长江大桥组合索塔锚固结构钢-混传剪构造足尺模型试验研究 被引量:2
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作者 赵灿晖 王康康 +1 位作者 沈孔健 郑清刚 《桥梁建设》 EI CSCD 北大核心 2024年第1期31-38,共8页
常泰长江大桥索塔锚固结构采用钢箱-核芯混凝土组合结构,为研究该新型组合索塔锚固结构钢-混传剪构造的受力特性,进行钢-混传剪构造足尺模型试验研究。制作2个锚固结构足尺节段试验模型,通过压剪试验研究锚固结构的荷载~滑移曲线及应力... 常泰长江大桥索塔锚固结构采用钢箱-核芯混凝土组合结构,为研究该新型组合索塔锚固结构钢-混传剪构造的受力特性,进行钢-混传剪构造足尺模型试验研究。制作2个锚固结构足尺节段试验模型,通过压剪试验研究锚固结构的荷载~滑移曲线及应力、应变分布等受力特性,并通过有限元模型分析锚固结构的传力机理和各组件的内力分配比例,推导剪力钉剪力计算方法。结果表明:在2.14倍单索最大索力荷载作用下,锚固结构保持弹性状态,钢壁板未产生明显滑移,钢-混界面最大滑移不超过0.25 mm,该锚固结构中钢-混传剪构造至少具有2.14倍的安全系数;荷载作用下,剪力钉剪力从上至下逐渐增大,锚腹板附近底部3排剪力钉剪力较大,钢-混传剪构造至少存在剪力钉和界面摩擦力2种传剪机制,钢-混传剪构造的承载能力显著提高;钢-混传剪构造受力过程分为粘结力传力阶段和局部滑移阶段,剪力钉剪力分布不仅与沿剪切方向长度分布有关,也与荷载的大小线性相关。 展开更多
关键词 斜拉桥 组合索塔锚固结构 钢-混传剪构造 荷载~滑移曲线 足尺模型试验 有限元法
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脱空混凝土管道纵向力学行为及自膨胀高聚物注浆修复性能提升
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作者 李斌 方宏远 +2 位作者 杜雪明 孙明明 薛冰寒 《工程力学》 EI CSCD 北大核心 2024年第11期134-144,共11页
为揭示脱空混凝土管道的纵向力学行为以及自膨胀高聚物外部注浆修复性能提升效果,开展了密实、脱空和高聚物修复混凝土管道现场足尺试验和三维有限元数值仿真,并通过试验结果对数值模型进行了验证。以不同管基状态下混凝土管道的截面纵... 为揭示脱空混凝土管道的纵向力学行为以及自膨胀高聚物外部注浆修复性能提升效果,开展了密实、脱空和高聚物修复混凝土管道现场足尺试验和三维有限元数值仿真,并通过试验结果对数值模型进行了验证。以不同管基状态下混凝土管道的截面纵向弯曲弯矩和管顶竖向位移为分析对象,讨论了脱空宽度和脱空长度对混凝土管道力学行为的影响规律,并引入纵向弯矩和竖向位移修复指数ξM和ξU,对高聚物注浆修复脱空管道的性能提升效果进行了量化表征。研究表明:脱空管道正负纵向弯矩分别分布在脱空两侧的相邻管段和接头,峰值分别位于SgL2、SgR2和SgL3、SgR3处;脱空管道纵向弯矩在SgL1和SgR1处随脱空宽度的增大而减小,其余测点处随脱空宽度的增大而增大,在整个纵向随脱空长度的增大而增大;不同脱空宽度和脱空长度管道的纵向弯矩在SgL1和SgR1以外均高于密实管道;与密实管道相比,脱空管道竖向位移和接头剪切位移的最大增幅分别为155%和230%;修复管道的纵向弯矩略低于密实管道,竖向位移略高于密实管道,纵向弯矩和竖向位移最大修复指数分别为76.5%和83.7%。 展开更多
关键词 脱空管道 注浆修复 足尺试验 有限元模型 力学行为 性能提升
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超高性能混凝土加固盾构隧道结构试验与数值研究
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作者 柳献 纪汉卿 +2 位作者 甘海杰 孙雪兵 王金龙 《同济大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第11期1720-1730,共11页
在应用超高性能混凝土(UHPC)加固既有盾构隧道的基础上,提出优化的钢板-UHPC组合加固方法。将钢板作为隧道内衬并在钢板与管片之间填充UHPC,采用植筋、化学锚栓以及栓钉等作为界面连接件,形成共同受力的整体。开展极限承载力足尺试验并... 在应用超高性能混凝土(UHPC)加固既有盾构隧道的基础上,提出优化的钢板-UHPC组合加固方法。将钢板作为隧道内衬并在钢板与管片之间填充UHPC,采用植筋、化学锚栓以及栓钉等作为界面连接件,形成共同受力的整体。开展极限承载力足尺试验并建立非线性数值模型,探究组合加固结构的破坏机理以及影响受力性能的关键因素。结果表明,组合加固结构破坏模式具有较好的延性特征;组合加固结构刚度主要受管片及加固体刚度控制,承载力水平主要受管片强度控制,极限承载力相比UHPC加固结构提升28%;极限状态下,顶部和腰部等位置的钢板发生屈服、主筋受拉屈服。数值参数分析结果表明,组合加固结构性能指标受加固层厚度和界面黏结性能影响较大,可适当增大钢板厚度并保证界面连接件的数量。 展开更多
关键词 隧道工程 盾构隧道 加固 足尺试验 超高性能混凝土(UHPC) 极限承载力
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隧道火灾临界风速模型的差异与适用性分析
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作者 孙峰 李江栋 +1 位作者 王小飞 吴珂 《消防科学与技术》 CAS 北大核心 2024年第9期1272-1277,共6页
临界风速是纵向通风隧道防排烟设计的重要指标,目前广泛采用的临界风速模型分为临界弗洛德数模型(世界道路协会PIARC推荐)和分段函数模型(美国消防协会NFPA推荐)两类,但两种公式的计算结果差异显著,给隧道防火设计造成了困扰。本文分析... 临界风速是纵向通风隧道防排烟设计的重要指标,目前广泛采用的临界风速模型分为临界弗洛德数模型(世界道路协会PIARC推荐)和分段函数模型(美国消防协会NFPA推荐)两类,但两种公式的计算结果差异显著,给隧道防火设计造成了困扰。本文分析了PIARC公式和NFPA公式在不同火源功率、隧道宽度、隧道高度下计算临界风速的差异及成因,同时结合隧道火灾全尺寸试验、数值模拟对比了两种公式计算结果的控烟效果,并与已有的全尺寸和比尺模型试验数据比较论证了两公式的适用性。结果表明,受临界弗洛德数取值和均匀混合假定的制约,PIARC公式无法准确反映临界风速随火源功率的变化规律,公式计算结果明显偏小,且误差随着宽高比的增大而增大;而NFPA公式更加全面地考虑了火羽流状态与隧道断面尺寸之间的相对关系对临界风速的影响,计算结果具有更好的烟气控制效果,且与试验数据更为吻合;NFPA公式可以适用于大部分隧道断面和火源功率条件下的临界风速计算,而PIARC公式仅适用于断面宽高比较小(AR≤1)和火源功率较大(HRR≥15MW)时的临界风速计算。 展开更多
关键词 隧道火灾 纵向通风 临界风速 全尺寸试验 数值模拟 适用性
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管道环焊缝拉伸应变容量模型分析及改进
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作者 王昊 张浩楠 +4 位作者 吴圣思 吴江桥 张振永 刘啸奔 张宏 《石油机械》 北大核心 2024年第3期108-116,共9页
为了确保石油天然气管线在复杂服役环境下的本质安全,探讨了目前国内外广泛应用的3种管道环焊缝拉伸应变容量模型(CSA Z662、PRCI-CRES、EXXON MOBIL),并对其参数选取范围性进行了汇总和对比分析。通过分析模型预测值和96组全尺寸管道... 为了确保石油天然气管线在复杂服役环境下的本质安全,探讨了目前国内外广泛应用的3种管道环焊缝拉伸应变容量模型(CSA Z662、PRCI-CRES、EXXON MOBIL),并对其参数选取范围性进行了汇总和对比分析。通过分析模型预测值和96组全尺寸管道及宽板拉伸试验数据的差异,对各拉伸应变容量模型在不同钢级下的预测精度进行了验证,并使用90%置信上限倒数法计算了模型安全系数。结果表明:由于CSA Z662模型断裂韧性取值上限过小,导致其对于中、高钢级管线的预测值过于保守;EXXON MOBIL和PRCI-CRES模型更为完善,二者预测结果相似,并与试验结果较为相符。针对EXXON MOBIL和PRCI-CRES模型计算所得的安全系数可以明显改善模型预测结果,可将非保守预测值最大误差控制在约30%范围内,从而有效满足较为保守的设计要求。研究结果可为管线基于应变设计提供理论指导。 展开更多
关键词 环焊缝 拉伸应变容量模型 本质安全 全尺寸试验 宽板试验 断裂韧性
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乡村旅游地居民公民意识量表开发与检验
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作者 杨金华 肖宁 +2 位作者 章锦河 李谦 刘佳敏 《资源开发与市场》 CAS 2024年第5期641-648,共8页
乡村振兴旨在促进乡村经济、社会和文化的全面发展,乡村居民作为乡村发展的主体,其公民意识的觉醒和提升是实现乡村振兴的关键。目前学术界对乡村旅游地居民公民意识的研究涉及较少,能测量的量表更是少见。以乡村旅游地居民为研究对象,... 乡村振兴旨在促进乡村经济、社会和文化的全面发展,乡村居民作为乡村发展的主体,其公民意识的觉醒和提升是实现乡村振兴的关键。目前学术界对乡村旅游地居民公民意识的研究涉及较少,能测量的量表更是少见。以乡村旅游地居民为研究对象,通过文献回顾和半结构化访谈,提炼出乡村旅游地居民公民意识的核心内涵及结构维度;在此基础上,通过专家咨询、问卷预调研等方式确定居民公民意识的初始量表,并对安徽宏村、湖南张谷英村和靖港古镇3个乡村旅游地所在居民开展问卷调查。研究发现:乡村旅游地居民公民意识量表由主体意识、法律意识和公共意识3个维度,共10个测项构成,量表的信效度俱佳。 展开更多
关键词 乡村旅游 公民意识 乡村居民 量表开发 量表检验
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