初始位移作用下车身振动系统的能量消耗
周长峰,张家豪,鲁大坤,刘立邦,娄光浩
山东交通学院汽车工程学院,山东济南250357
摘要:为研究车身垂向振动过程中减振器的能量消耗特性,推导初始位移状态下减振器在一个周期内消耗的能量(阻力功)的计算公式,得知仅在初始位移作用下,车身振动系统减振器消耗的能量只与阻尼比有关,与车身振动系统的固有频率无关。研究表明:对于单自由度振动系统,系统的阻尼比大于0.3时,减振器在一个周期内消耗的能量占初始位移状态输入系统功的98%,分别减小阻尼系数、增大质量、增大刚度,都会使减振器在一个周期内消耗的能量减少,振荡持续时间延长,有利于车身振动系统模态参数的测量。
关键词:初始位移;单自由度;车身垂向振动;能量消耗
Energy consumption characteristics of body vibration system under initial displacement
ZHOU Changfeng, ZHANG Jiahao, LU Dakun, LIU Libang, LOU Guanghao
School of Automotive Engineering, Shandong Jiaotong University, Jinan 250357, China
Abstract:To research the energy consumption characteristics of damper in the vertical vibration process of body, the formula is deduced to calculate the resistance in one period under the initial displacement condition. It can be concluded from the formula that the energy consumed by the damper is only affected by the damping ratio and is independent of the natural frequency of the vibration system. The research shows that for the single freedom vibration system the energy consumption in one period accounts for 98% of the input power of the initial displacement state when the damping ratio is over 0.3; the energy consumption of damper in one period will decline when decreasing the damping coefficient, increasing mass and stiffness; meanwhile the oscillation of system becomes more evident, which is beneficial to measure the modal parameters of the body vibration system.
Keywords:initial displacement; single degreeoffreedom; vertical vibration of body; energy consumption
考虑制动间隙的电子机械制动系统
三阶闭环PID控制策略
张帅,梁光成,常宏,郭金刚*
长安大学汽车学院,陕西西安710064
摘要:考虑制动间隙,分析电子机械制动(electromechanical brake,EMB)系统的控制策略,研究EMB系统从制动开始到制动结束的控制方法,建立包含制动间隙控制在内的EMB执行器比例积分微分(proportional integral differential,PID)控制策略,在Matlab/Simulink中进行仿真,改变EMB控制系统输入端的目标夹紧力,观察有无制动间隙时EMB系统夹紧力和电机转速的变化。仿真结果表明:该控制策略能提高EMB的响应速度和控制精度,尽快消除制动间隙,满足预期要求。
关键词:电子机械制动系统;制动间隙控制;三阶闭环PID控制;仿真
Threeorder closedloop PID control strategies of electromechanical brake system with brake clearance
ZHANG Shuai, LIANG Guangcheng, CHANG Hong, GUO Jingang
School of Automobile, Chang′an University, Xi′an 710064, China
Abstract: Considering the brake clearance, the control strategies of the electromechanical brake system (EMB) is analyzed to study the control method of EMB system from the beginning to the end of braking and establish the control strategies of the proportion, integration and differentiation (PID) of the EMB actuator including the brake clearance control. They are simulated in the Matlab/Simulink to change the target clamping force of EMB brake at the end of input and observe the changes in the clamping force of EMB system and motor speed with or without the brake clearance. The simulation results show that the control strategies can improve the response speed and control accuracy of EMB, eliminate the brake clearance as soon as possible, and meet the expected requirements.
Keywords:electromechanical brake system; brake clearance control; threeorder closedloop PID control; simulation
基于网格模型与KMeans算法的交通状态演变特征
李甜1,李瑞玲1,张萌萌1,宋欣航2,王帅琦1
1.山东交通学院交通与物流工程学院,山东济南250357;2.西南交通大学利兹学院,四川成都610000
摘要:为利用海量网约车轨迹数据实现对城市交通状态的高效识别与分类,对成都市网约车轨迹数据进行预处理,构建城市交通状态识别网格模型,根据模型判别网格的交通状态。利用KMeans聚类算法对不同时段的交通状态进行聚类,并将交通状态分为持续畅通型、轻度缓行型、持续缓行型、持续拥堵型4种类型,从时间维度和空间维度分析不同网格的交通状态演变特征。结果表明:研究区域内交通状态相对稳定,持续拥堵区域分散,持续缓行区域较为集中。基于网格模型与KMeans算法的交通状态识别方法能够实现对交通状态的快速判别与聚类,可实现对不同城市交通状态的识别。
关键词:交通状态;网约车轨迹数据;网格模型;KMeans
Evolution characteristics of traffic state based on grid model and KMeans algorithm
LI Tian1, LI Ruiling1, ZHANG Mengmeng1, SONG Xinhang2, WANG Shuaiqi1
1. School of Transportation and Logistics Engineering, Shandong Jiaotong University, Jinan 264209, China;2. University of Leeds, Southwest Jiaotong University, Chengdu 610000, China
Abstract:In order to realize the efficient identification and classification of urban traffic state by using the massive netcharted cars′ trajectory data, the netcharted cars′ trajectory data of Chengdu City are preprocessed to establish the grid model of the urban traffic state recognition and judge the traffic state of the grid by the model. The KMeans clustering algorithm is used to collect the traffic state data at different periods, then the traffic states are divided into four types of the smooth flow, mild flow, continuous flow and continuous congestion, and finally the evolution characteristics of different grids of traffic states are analyzed from the time and spatial dimensions. The results show that the traffic states in the researched area are relatively stable, the continuous congestion area is scattered, and the slow flow area is more concentrated. So, the recognition method of the traffic states based on the grid model and KMeans algorithm can implement the rapid measurement and clustering of traffic states and also the recognition of traffic states in different cities.
Keywords: traffic sate; netcharted cars′ trajectory data;grid model; KMeans
低改高高速公路路桥过渡段加宽沉降规律
李友云1,安钢1,谢继登2,赵秀艳3,何敏1
1.长沙理工大学交通运输工程学院,湖南长沙410114; 2. 保利长大工程有限公司,广东广州510000;3.中国建设第五工程局有限公司第三建设有限公司,湖南长沙410000
摘要:为研究低改高高速公路路桥过渡段加宽后路基的沉降特性,通过有限元建模分析,研究低改高高速公路路桥过渡段加宽的横、纵向断面沉降位移。结果表明:在横断面上,道路沉降主要集中在填筑期及工后5 a内,地基表面竖向位移整体趋近于“盆”形,距离旧路基越远沉降越明显,拓宽侧工后沉降主要集中在2 a内,占工后沉降的64%,在加宽路基中心附近达到最大,水平位移与路基沉降有关。路基拼接位置及加宽路基边坡局部剪应力集中;纵断面上,路基及地基沉降均由桥台向一般路基逐渐增大,差异沉降表现在台后15 m范围内,运营15 a桥台与台后15 m间总差异沉降为72 cm,其中工后差异沉降30 cm,纵断面剪应力主要集中在台背换填区及桩底区域。
关键词:高速公路路桥过渡段;地基表面竖向位移;横向沉降位移;纵向沉降位移;桥台
Law of widening settlement of roadbridge transition section of lowtohigh expressway
LI Youyun1, AN Gang1, XIE Jideng2, ZHAO Xiuyan3, HE Min1
1.School of Traffic and Transportation Engineering, Changsha University of Science & Technology, Changsha 410114, China;2. Poly Changda Engineering Co., Ltd., Guangzhou 510000, China;3. Third Construction Co., Ltd., China Construction Fifth Engineering Division Corp., Ltd., Changsha 410000, China
Abstract:In order to study the subgrade settlement characteristics of widened transition section of lowtohigh expressway, the settlement displacement of widened transition section of the transverse and longitudinal section of the lowtohigh expressway is studied by the analysis of the finite element modeling. The results show that on the crosssection, the road settlement is mainly concentrated in the filling period and within 5 years after construction. The vertical displacement of the foundation surface shows a “basin” trend as a whole. The settlement of the widened side is mainly concentrated in 2 years, accounting for 64% of the post construction settlement and reaching the maximum near the center of the widened subgrade. The horizontal displacement is related to the subgrade settlement. Local shear stress is concentrated at the subgrade splicing position and the widened subgrade slope; on the longitudinal section, the settlement of the subgrade and the foundation gradually increases from the bridge abutment to the general subgrade, and the differential settlement is manifested within 15 m behind the platform. When the 15year bridge has been operated, the total differential settlement between the platform and the 15m behind the platform is 7.2 cm, of which the differential settlement after construction is 3.0 cm. The longitudinal shear stress is mainly concentrated in the backfill area and the pile bottom area.
Keywords:transition section of expressway bridge; vertical displacement of foundation surface; lateral settlement displacement; longitudinal settlement displacement; bridge abutment
混合梁桥钢混结合段合理布置位置的优化
黄国红1,官彩依2,卓为顶3
1.南京市公共工程建设中心,南京210019;2.东南大学土木工程学院, 南京211189;3.南京工程学院建筑工程学院, 南京211167
摘要:为合理布置钢-混凝土混合梁桥钢混结合段位置,基于中墩截面弯矩等效和边支座支反力控制原则,采用结构力学位移法建立力学和数学计算模型,推导三跨混合连续梁桥中跨钢梁长度占比的合理取值范围,获得三跨混合连续梁桥的跨径布置及结合段合理位置(边中跨比与中跨钢梁长度占比)之间的关系或可行域范围。以南京机场二通道秦淮新河桥为例,计算钢混结合段的合理位置,结果表明:采用上述设计方法得到边中跨比与中跨钢梁长度占比处于合理范围,设计方法正确可行。
关键词:混合连续梁桥;结合段合理位置;中墩截面弯矩等效原则;边支座支反力控制原则
Optimization of rational location of steelconcrete joint in hybrid girder bridges
HUANG Guohong1, GUAN Caiyi2, ZHUO Weiding3
1. Nanjing Public Engineering Construction Center, Nanjing 210019, China;2. School of Civil Engineering, Southeast University, Nanjing 211189, China;3. School of Architecture Engineering, Nanjing Institute of Technology, Nanjing 211167, China
Abstract:The rational location of steelconcrete joint is one of the critical problems in the design of hybrid girder bridges. This paper proposes the principles of moment equivalence of middle pier and reaction force of side support. Based on the displacement method of structural mechanics, the mechanical and mathematical calculation models are established, and the reasonable value range of the length proportion of steel girder is derived. The relationship of the span layout and the rational location of joint section (i.e. sidespantomidspan ratio and the length proportion of steel girder) are obtained. Taking Qinhuai Bridge on the second channel to Nanjing airport as an example, the rational location of steelconcrete joint is calculated, which shows the validity and accuracy of this design method.
Keywords:hybrid continuous girder bridge; ration location of steelconcrete joint; moment equivalence of middle pier; reaction force of side support
盾构近距离下穿运营地铁隧道同时接收施工技术
耿传政
中铁十四局集团隧道工程有限公司,山东济南250022
摘要:以成都轨道交通6号线玉双路站—牛王庙站区间双线隧道近距离下穿运营2号线,同时进行盾构接收施工工程为背景,阐述盾构下穿前、中、后以及接收施工阶段的大管棚支护、多重注浆、刀具调整、掘进参数设定、自动化监测以及快速接收、洞门封闭处理等关键施工技术。在成都卵石和泥岩复合地层中盾构施工时,通过采取大管棚预加固、自动化监测等技术措施,有效提升盾构在接收段下穿运营地铁线的施工安全系数,避免监测盲区。
关键词:盾构;地铁隧道;大管棚;自动化监测;接收
Construction technology of shield passing through operating subway tunnel and simultaneously receiving
GENG Chuanzheng
Tunnel Engineering Co., Ltd., China Railway 14th Bureau Group Co., Ltd., Jinan 250022, China
Abstract:Taking the double track tunnel between Yushuang Road station and Niuwangmiao station of Chengdurail transit line 6 passing through the tunnel of line 2 at close distance, the shield receiving construction project is taken as the background. The key construction technologies, such as the large pipe shed support, multiple grouting, cutter adjustment, tunneling parameter setting, automatic monitoring, rapid receiving and portal closure treatment, are described before, during, after and in the process of the receiving construction stage of shield tunneling. It is verified that during the shield construction of the composite stratum of pebble and mudstone in Chengdu, the construction safety factor of shield passing through the operating subway line in the receiving section can be effectively improved by adopting technical measures such as the prereinforcement of the large pipe shed and automatic monitoring so that the monitoring blind area is avoided.
Keywords:hield machine; metro tunnel; large pipe shed; automatic monitoring; reception
基于无缝分区技术的似大地水准面精化方法
戴一,胡伍生
东南大学交通学院,江苏南京211189
摘要:为提高似大地水准面模型的精度,改善常用二次多项式拟合模型的缺点,提出基于无缝分区技术和二次曲面拟合相结合的似大地水准面精化方法,并利用江苏省C级全球定位系统(global positioning system,GPS)水准网数据进行工程试验验证。结果表明:与二次多项式模型相比,该方法的精度提高了80%,证实了其在工程应用中的有效性。
关键词:似大地水准面精化;二次多项式模型;无缝分区技术;GPS
Refinement method of quasigeoid based on seamless zoning technique
DAI Yi,HU Wusheng
School of Communications, Southeast University, Nanjing 211189, China
Abstract:In order to improve the accuracy of the quasigeoid model and improve the shortcomings of the commonly used quadratic polynomial fitting models, a quasigeoid refinement method based on seamless partition technology and quadric surface fitting is proposed, and the level network data of Jiangsu Province Clevel the global positioning system (GPS) is verified by engineering tests. The results show that: compared with the quadratic polynomial model, the accuracy of this method is increased by 80%, which confirms its effectiveness in engineering applications.
Keywords:quasigeoid refinement; quadratic polynomial model; seamless partition technology; GPS
基于遥感数据的土地资源分类方法比较
王蕊1,程海龙2,黄如兵3
1.山东交通学院交通土建工程学院,山东济南250357; 2.中国水电八局有限公司,湖南长沙410004;3.中国重型汽车集团有限公司,山东济南250101
摘要:为对比分析基于遥感数据的各种土地资源分类方法的精度,找到适合区域土地资源的分类方法,以安徽省安庆市怀宁县为研究区域,以Landsat遥感影像为数据源,分别采用KMeans、最大似然、最小距离、基于专家知识的决策树4种分类方法进行该研究区域的土地资源分类,对分类结果图和谷歌卫星图进行比较,分析4种分类方法的分类精度。结果表明:KMeans、最大似然、最小距离、基于专家知识的决策树4种分类方法下的遥感图像分类图总体精度分别为93.07%、96.63%、94.91%、97.23%,Kappa系数分别为76.18%、89.94%、8483%、91.75%,说明基于专家知识的决策树分类方法精度最高,该分类方法更适合该区域的土地资源分类。
关键词:遥感数据;土地资源;分类方法;分类精度;比较
Comparison of land resources classification methods based on remote sensing data
WANG Rui1, CHENG Hailong2,HUANG Rubing3
1. School of Civil Transportation Engineering, Shandong Jiaotong University, Jinan 250357, China;2. Sinohydro Bureau 8 Co., Ltd., Changsha 410004, China; 3. China National Heavy Duty Truck Group Co.,Ltd., Jinan 250101, China
Abstract:In order to compare and analyze the accuracy of various land resources classification methods based on remote sensing data, and find the classification method suitable for regional land resources, Huaining County of Anqing City in Anhui Province is taken as the research area and Landsat remote sensing images are used as the data source. Four different methods, such as KMeans, maximum likelihood, minimum distance and decision tree based on expert knowledge are used to classify land resources in the research area. The classification results and Google satellite images are compared to analyze the classification accuracy of the four classification methods. The results show that the overall accuracy of remote sensing image classification map under the four classification methods is 93.07%, 96.63%, 94.91%, and 97.23%, and the Kappa coefficients are 76.18%, 89.94%, 84.83%, and 91.75% respectively.The results demonstrate that the classification method with decision tree based on expert knowledge is better in accuracy, which means the decision tree method is more suitable for the land resources classification in this area .
Keywords:remote sensing data; land resources; classification method; classification accuracy; comparison
富水砂卵石地层盾构刀具磨损原因及改进
韩伟1,王余鹏1,石端文2
1.福建林业职业技术学院,福建南平353000;2.中铁第四勘察设计院集团有限公司,湖北武汉430000
摘要:为研究盾构机掘进砂卵石地层时刀具的磨损机理,以福州某地铁盾构施工为例,分析原施工方案存在的问题及引起盾构刀具过度磨损的原因。为改善土壤性能,在每m3渣土中分别添加150 L泥浆和350 L泡沫;采用辐条式刀盘代替原面板式刀盘;采用主、副切削刀,主超前刀,鱼尾刀,盘圈贝型刀,周边刮刀等刀具,并优化刀具在刀盘上的布置。测量计算刀具磨损量及磨损系数,分析土压平衡盾构穿越富水砂卵石地层段的刀具磨损量与切削轨迹的关系。分析表明:优化后刀具的平均磨损系数由0.565 mm/km降至0.013 mm/km,优化后的方案能有效减小盾构刀具在富水砂卵石地层中的过快磨损,显著延长刀具使用寿命,有效提高土压平衡盾构机的施工效率。
关键词:富水砂卵石地层;刀具磨损;土壤改良;刀盘;刀具布置
Wear cause and improvement of cutting tool on shield machine in waterrich stratum
HAN Wei1, WANG Yupeng1, SHI Duanwen2
1. Fujian Forestry Vocational College, Nanping 353000, China;2. China Railway Siyuan Survey and Design Group Co., Ltd., Wuhan 430000, China
Abstract: Taking the shield construction of a subway in Fuzhou as an example, the existing problems in the original construction plan and the excessive wear causes of the cutters on the shield machine are analyzed in order to study the wear mechanism of the cutters when the shield machine is digging into the sand gravel layer. To improve the soil performance, 150 L mud and 350 L foam per m3 are added to the residue soil. At the same time, the original paneltype cutter head is replaced with the spoketype cutter head to optimize the tool arrangement on the cutter head, where the main and auxiliary cutters, the peripheral scraper, the main leading cutter, the fishtail cutter, the coil shell type cutter, the rim shell cutter and other tools are used. The tool wear and wear coefficient are measured and calculated to analyze the relationship between the tool wear and the cutting path of the earthpressure balance shield machine passing through the waterrich stratum. The analysis shows that the average wear coefficient of the tool after optimization is reduced from 0.565 mm/km to 0.013 mm/km. The optimized scheme can effectively reduce the rapid wear of shield tools in the waterrich stratum, significantly extend the service life of the tools, and effectively improve the construction efficiency of the earthpressure balance shield machine.
Keywords:waterrich stratum; tool wear; soil improvement; cutter head; tool arrangement
基于OptiStruct的万向联轴叉头孔两侧圆弧结构优化
胡斌1, 谭邦俊1,张宝霞1,王艳1,何贵生2, 彭超3
1.滁州职业技术学院机械与汽车工程学院,安徽滁州239000;2.锐志微创医疗科技(常州)有限公司,江苏常州231000;3.松下家电(中国)有限公司,浙江杭州310000
摘要:针对万向联轴叉头孔两侧圆弧出现最大应力,导致叉头断裂的问题,采用有限元HyperMesh软件对其进行力学分析,得到叉头两侧圆弧处的最大应力和最大位移。并利用OptiStruct软件对其进行拓扑优化,最大应力从244.9 MPa下降到213.2 MPa,最大形状位移改变了6.39 mm。以最大形状位移为理论依据,对叉头进行结构改进。研究结果表明:以拓扑优化结论为依据改进叉头两侧圆弧结构,既降低了叉头间隙处最大应力,又满足叉头加工生产的要求。
关键词:叉头;拓扑优化;结构改进;应力
Optimization of arc structure on both sides of fork head based on OptiStruct
HU Bin1,TAN Bangjun1,ZHANG Baoxia1,WANG Yan1,HE Guisheng2,PENG Chao3
1.College of Machanical and Automotive Engineering,Chuzhou Polytechnic,Chuzhou 239000,China;2.Ruizhi Minimally Invasive Medical Technology (Changzhou) Co.,Ltd.,Changzhou 231000,China;3.Panasonic Home Appliances (China) Co., Ltd.,Hangzhou 310000,China
Abstract:In view of the maximum stress at the both sides of the universal coupling fork head, the fork breaks.The finite element HyperMesh software is used to carry out the mechanical analysis, and the maximum stress and displacement at the both sides of the fork head is obtained.The maximum stress decreased from 244.9 MPa to 213.2 MPa, and the maximum shape displacement changed by 6.39 mm.Based on the topology optimization of 6.39 mm, the structure of the fork head is improved.The results show that the improvement of the clearance structure of the fork head assembly based on the conclusion of topology optimization not only reduces the maximum stress at the both sides of the fork head, but also meets the requirements of the fork head processing and production.
Keywords:fork head; topology optimization; structural improvement; stress
二维TMDs Janus材料研究进展
孙翠翠,吴艳玲,王晓宁,丁永玲
山东交通学院交通土建工程学院, 山东济南250357
摘要:为了研究二维单层过渡金属硫属化物(transition metal dichalcogenides,TMDs)Janus材料的结构及特性,介绍二维TMDs Janus材料的研究背景,分析其结构和稳定性,阐述从传统二维材料到二维TMDs Janus材料的制备方法,分析TMDs Janus材料由于其反演对称性的破坏显示出的新颖特性以及进一步开发二维TMDs Janus材料的未来前景。研究表明:二维TMDs Janus材料除了拥有其他普通二维材料的优异性能外,还显示出强的Rashba自旋分裂、大的垂直压电系数和次谐波生成响应,故二维TMDs Janus材料在新型光电和机电设备的开发中具有很大的潜力。
关键词:TMDs Janus材料;Rashba效应;压电极化效应;次谐波产生效应
Research development of twodimensional TMDs Janus material
SUN Cuicui, WU Yanling, WANG Xiaoning, DING Yongling
School of Transportation and Civil Engineering, Shandong Jiaotong University, Jinan 250357, China
Abstract:In order to study the structure and characteristics of the single layer of the twodimensional (2D) TMDs Janus material, the research background of the 2D TMDs Janus material is introduced, its structure and stability are analyzed, the preparation methods from the traditional 2D material to the 2D TMDs Janus material are described, and the novel characteristics of the 2D TMDs Janus material which result from the destruction of its inversion symmetry and the future prospects of the 2D TMDs Janus material are presented. The research shows that in addition to the excellent performance of other ordinary 2D materials, the 2D TMDs Janus material shows the strong Rashba spin splitting, the large vertical piezoelectric coefficient and the second harmonic generation response, so the various Janus materials based on 2D materials have great potential in the development of the new photoelectric and electromechanical equipment.
Keywords:TMDs Janus material; Rashba effect; piezoelectric effect; secondharmonic generation effect