To analyze the dynamic response and reliability of a continuous beam bridge under the action of an extra heavy vehicle, a vehicle–bridge coupled vibration model was established based on the virtual work principle and...To analyze the dynamic response and reliability of a continuous beam bridge under the action of an extra heavy vehicle, a vehicle–bridge coupled vibration model was established based on the virtual work principle and vehicle–bridge displacement compatibility equation, which can accurately simulate the dynamic characteristics of the vehicle and bridge. Results show that deck roughness has an important function in the effect of the vehicle on the bridge. When an extra heavy vehicle passes through the continuous beam bridge at a low speed of 5 km/h, the impact coefficient reaches a high value, which should not be disregarded in bridge safety assessments. Considering that no specific law exists between the impact coefficient and vehicle speed, vehicle speed should not be unduly limited and deck roughness repairing should be paid considerable attention. Deck roughness has a significant influence on the reliability index, which decreases as deck roughness increases. For the continuous beam bridge in this work, the reliability index of each control section is greater than the minimum reliability index. No reinforcement measures are required for over-sized transport.展开更多
Based on the background of structural protection and Disaster Reduction Engineering, the dynamic behaviour and failure mechanism of restrained beams in portal steel frames in localised fire are investigated via experi...Based on the background of structural protection and Disaster Reduction Engineering, the dynamic behaviour and failure mechanism of restrained beams in portal steel frames in localised fire are investigated via experimental measurement and numerical simulation techniques. Comprehensive parametric studies are carried out to discuss the influence of end connection types, temperature, impact velocity,impact mass and span-to-depth ratio(SDR) on the dynamic response of the beams. The characteristics of deformation, internal force and energy distribution about the restrained beams and its joints are investigated. A temperature dependent criterion for evaluating the frame joint performance is proposed to measure the degree of performance degradation and impact resistance of the joint. The dynamic displacement amplification factor in different temperature environments are proposed for the different beam end constraint types and SDRs. Results of the experimental and numerical analysis show that the welded connection(WC) of three typical joint types is the strongest, and the extended endplate connection(EEC) is the weakest in terms of the impact resistance performance. With regard to the failure mode of the joint, the failure positions of the WC and the welded-bolted connection are located in the inner web of the column. Meanwhile, the EEC is located in the connection position between the beam and the endplate. Three different internal force stages and two obvious critical temperature boundaries of the restrained beams emerge with the increase in temperature, and they have significant characteristics in terms of deformation trend, internal force transfer and energy distribution. During the impact, a phenomenon known as “compression arch action” develops into “catenary action” with the increase in deflection in the frame beam mechanism.展开更多
随着智能网联、人机交互和自动驾驶技术的不断演进,汽车智能化的发展正在重新定义驾驶体验,并重新塑造了未来出行方式。在此背景下,多模态交互已经成为智能汽车行业重要创新手段,该领域的研究也不断涌现新的课题和机遇。鉴于此,深入探...随着智能网联、人机交互和自动驾驶技术的不断演进,汽车智能化的发展正在重新定义驾驶体验,并重新塑造了未来出行方式。在此背景下,多模态交互已经成为智能汽车行业重要创新手段,该领域的研究也不断涌现新的课题和机遇。鉴于此,深入探讨了该领域的研究现状,将Web of Science核心数据集的科学引文索引和Scopus数据库中汽车多模态交互的相关文献作为研究对象,利用CiteSpace文献计量工具对其进行图谱可视化分析,对该领域的发展历程和现状进行脉络梳理,探析研究热点及方向,并对未来研究趋势进行预测。展开更多
随着感知技术的不断发展以及智能交通基础设施的完善,智能网联汽车应用在自动驾驶领域的地位逐渐提升.自动驾驶感知从单车智能向车路协同迈进,近年来涌现出一批新的协同感知技术与方法.本文旨在全面阐述面向智能网联汽车的车路协同感知...随着感知技术的不断发展以及智能交通基础设施的完善,智能网联汽车应用在自动驾驶领域的地位逐渐提升.自动驾驶感知从单车智能向车路协同迈进,近年来涌现出一批新的协同感知技术与方法.本文旨在全面阐述面向智能网联汽车的车路协同感知技术,并总结相关可利用数据及该方向的发展趋势.首先对智能网联汽车的协同感知策略进行划分,并总结了不同感知策略具备的优势与不足;其次,对智能网联汽车协同感知的关键技术进行阐述,包括车路协同感知过程中的感知技术与通信技术;然后对车路协同感知方法进行归纳,总结了近年来解决协同感知中感知融合(Perception fusion,PF)、感知信息选择与压缩(Perception selection and compression,SC)等问题的相关研究;最后对车路协同感知的大规模数据集进行整理,并对智能网联汽车协同感知的发展趋势进行分析.展开更多
基金Project(50779032)supported by the National Natural Science Foundation of ChinaProject(20090451330)supported by the Postdoctoral Foundation of ChinaProject(BS2013SF007)supported by Shandong Scientific Research Award Foundation for Outstanding Young Scientists,China
文摘To analyze the dynamic response and reliability of a continuous beam bridge under the action of an extra heavy vehicle, a vehicle–bridge coupled vibration model was established based on the virtual work principle and vehicle–bridge displacement compatibility equation, which can accurately simulate the dynamic characteristics of the vehicle and bridge. Results show that deck roughness has an important function in the effect of the vehicle on the bridge. When an extra heavy vehicle passes through the continuous beam bridge at a low speed of 5 km/h, the impact coefficient reaches a high value, which should not be disregarded in bridge safety assessments. Considering that no specific law exists between the impact coefficient and vehicle speed, vehicle speed should not be unduly limited and deck roughness repairing should be paid considerable attention. Deck roughness has a significant influence on the reliability index, which decreases as deck roughness increases. For the continuous beam bridge in this work, the reliability index of each control section is greater than the minimum reliability index. No reinforcement measures are required for over-sized transport.
基金supported by the National natural Science Foundation of China [grant numbers 12172198, 11272189 and 52078283]Youth Innovation Technology Project of Higher School in Shandong Province [grant number 2019KJG015]。
文摘Based on the background of structural protection and Disaster Reduction Engineering, the dynamic behaviour and failure mechanism of restrained beams in portal steel frames in localised fire are investigated via experimental measurement and numerical simulation techniques. Comprehensive parametric studies are carried out to discuss the influence of end connection types, temperature, impact velocity,impact mass and span-to-depth ratio(SDR) on the dynamic response of the beams. The characteristics of deformation, internal force and energy distribution about the restrained beams and its joints are investigated. A temperature dependent criterion for evaluating the frame joint performance is proposed to measure the degree of performance degradation and impact resistance of the joint. The dynamic displacement amplification factor in different temperature environments are proposed for the different beam end constraint types and SDRs. Results of the experimental and numerical analysis show that the welded connection(WC) of three typical joint types is the strongest, and the extended endplate connection(EEC) is the weakest in terms of the impact resistance performance. With regard to the failure mode of the joint, the failure positions of the WC and the welded-bolted connection are located in the inner web of the column. Meanwhile, the EEC is located in the connection position between the beam and the endplate. Three different internal force stages and two obvious critical temperature boundaries of the restrained beams emerge with the increase in temperature, and they have significant characteristics in terms of deformation trend, internal force transfer and energy distribution. During the impact, a phenomenon known as “compression arch action” develops into “catenary action” with the increase in deflection in the frame beam mechanism.
文摘随着智能网联、人机交互和自动驾驶技术的不断演进,汽车智能化的发展正在重新定义驾驶体验,并重新塑造了未来出行方式。在此背景下,多模态交互已经成为智能汽车行业重要创新手段,该领域的研究也不断涌现新的课题和机遇。鉴于此,深入探讨了该领域的研究现状,将Web of Science核心数据集的科学引文索引和Scopus数据库中汽车多模态交互的相关文献作为研究对象,利用CiteSpace文献计量工具对其进行图谱可视化分析,对该领域的发展历程和现状进行脉络梳理,探析研究热点及方向,并对未来研究趋势进行预测。
文摘随着感知技术的不断发展以及智能交通基础设施的完善,智能网联汽车应用在自动驾驶领域的地位逐渐提升.自动驾驶感知从单车智能向车路协同迈进,近年来涌现出一批新的协同感知技术与方法.本文旨在全面阐述面向智能网联汽车的车路协同感知技术,并总结相关可利用数据及该方向的发展趋势.首先对智能网联汽车的协同感知策略进行划分,并总结了不同感知策略具备的优势与不足;其次,对智能网联汽车协同感知的关键技术进行阐述,包括车路协同感知过程中的感知技术与通信技术;然后对车路协同感知方法进行归纳,总结了近年来解决协同感知中感知融合(Perception fusion,PF)、感知信息选择与压缩(Perception selection and compression,SC)等问题的相关研究;最后对车路协同感知的大规模数据集进行整理,并对智能网联汽车协同感知的发展趋势进行分析.
