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Identification of Damage on Stringers By the PSO Method 用PSO方法识别桁条损伤
IF 0.4 Pub Date : 2021-09-01 DOI: 10.2478/sjce-2021-0016
M. Marton, M. Sokol, A. Bekö, Cao Maosen
Abstract The paper employs the particle swarm optimization (PSO) method for the identification of damage to a stringer web. This method is inspired by a swarm of bees or flock of birds which look for a common solution. It is a heuristic method, that utilizes a particle as a problem-solving candidate. The location of this particle in the search space represents the configuration of all the variables to possible solutions of the problem. As the particle moves into the solution space, the values of the variables change. The particle is defined by a position vector and a velocity vector. The resulting direction of the particle is determined by three components i.e. (1) the moment or inertia, (2) autobiographical or cognitive information and (3) social interaction. The quality of the particle is evaluated by a comparison function. In this study we tried to locate damage by using this method. The damage is represented by a rusted area on a stringer web, which was simulated as a change in the Young’s modulus. We used the modal calculation of the eigenfrequencies as an evaluation function.
摘要本文采用粒子群优化(PSO)方法对桁条腹板进行损伤识别。这种方法的灵感来自于一群蜜蜂或鸟类,它们寻找共同的解决方案。这是一种启发式方法,利用粒子作为解决问题的候选者。该粒子在搜索空间中的位置表示问题的可能解的所有变量的配置。当粒子移动到解决方案空间中时,变量的值会发生变化。粒子由位置矢量和速度矢量定义。粒子的最终方向由三个组成部分决定,即(1)力矩或惯性,(2)自传体或认知信息,以及(3)社会互动。粒子的质量通过比较函数进行评估。在这项研究中,我们试图通过使用这种方法来定位损伤。损伤由桁条腹板上的锈蚀区域表示,该区域被模拟为杨氏模量的变化。我们使用本征频率的模态计算作为评估函数。
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引用次数: 0
Evaluation of an Asphalt Mixture Containing a High Content of Reclaimed Asphalt and Different Crumb Rubber Modified Binders 含高含量再生沥青和不同胶粒改性粘结剂的沥青混合料的评价
IF 0.4 Pub Date : 2021-09-01 DOI: 10.2478/sjce-2021-0018
M. Belhaj, P. Vacková, J. Valentin
Abstract Recently, environmental concerns have become a primary driving force in most countries and industries dealing with natural resources. As a part of this category, asphalt pavement industry is trying to implement more green and sustainable features in its products, while maintaining the mechanical and performance-based properties of the resulting asphalt mixtures. Among potential recycled materials, vehicle tires and aged asphalt pavement have been demonstrated to show economic, ecological, and behavioral improvements in the mixtures. However, mixtures with a high content of reclaimed asphalt (RA) and crumb rubber present some limitations. Therefore, using another group of additives, i.e., a warm mix asphalt (WMA) additive, has been considered. The presented paper investigates the use of an elevated content of RA with different crumb rubber modified binders and (in some mixtures) a warm mix additive in an asphalt concrete (AC) binder mix. Regular empirical tests have been conducted and more advanced performance or functional characteristics, i.e., stiffness, thermal induced cracking, resistance to permanent deformation, complex modulus have been determined and evaluated. Selected results are presented in the paper.
摘要近年来,环境问题已成为大多数国家和行业处理自然资源问题的主要驱动力。作为这一类别的一部分,沥青路面行业正试图在其产品中实现更多的绿色和可持续功能,同时保持由此产生的沥青混合料的机械性能和性能。在潜在的再生材料中,汽车轮胎和老化沥青路面已被证明在混合料中显示出经济、生态和行为的改善。然而,具有高含量再生沥青(RA)和橡胶屑的混合物存在一些局限性。因此,考虑使用另一组添加剂,即温拌沥青(WMA)添加剂。本文研究了在沥青混凝土(AC)粘合剂混合物中使用不同的胶粉改性粘合剂和(在某些混合物中)温拌添加剂来提高RA含量。已经进行了定期的经验测试,并确定和评估了更先进的性能或功能特征,即刚度、热致开裂、抗永久变形性、复模量。文中给出了选定的结果。
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引用次数: 1
A Simplified Matrix Analysis Approach to Multi Storey Buildings Involving a Friction Damper 含摩擦阻尼器的多层建筑的简化矩阵分析方法
IF 0.4 Pub Date : 2021-09-01 DOI: 10.2478/sjce-2021-0015
K. Gharra, K. Khanlari, J. Asgari, Mohammad
Abstract Damping through friction tends to be one of the most efficient methods to suppress damage to structures from earthquakes. Realizing robust structures is therefore highly dependent on designing for the dynamic forces of friction- damped structures and exploring their reliability against natural disasters. This paper presents a simplified matrix analysis algorithm for multi-storey friction- damped buildings. We have analyzed the behavior of friction- damped systems more accurately by modeling the master-slave degree of freedom of the joints. First, the formulation of the problem is discussed, and a condensed general equation is derived. Then, an end- to- end solution is proposed to find the responses of structures. The displacement response of each storey has been carried out in both condensed and non-condensed general equations, and the results clearly show the accuracy of the proposed method. The numerical analysis and the results of the simulation of various friction- damped structures depicts the proposed approach consists with the commercial finite element method and is applicable for the analysis various types of structures. It is noted that the acceleration and displacement responses of the structures investigated under the proposed method and the traditional finite element method are so consistent that only a 1.5% difference is observed. Moreover, as a result of the proper allocation of degrees of freedom during the analysis, this method yields a reduction in computational costs especially in large buildings.
摘要摩擦阻尼往往是抑制地震对结构损伤的最有效方法之一。因此,实现结构的鲁棒性在很大程度上取决于摩擦阻尼结构的动力设计和对其抗自然灾害可靠性的探索。本文提出了一种多层摩擦阻尼建筑的简化矩阵分析算法。通过对关节主从自由度的建模,我们更准确地分析了摩擦阻尼系统的行为。首先,讨论了该问题的公式,导出了一个简明的一般方程。然后,提出了一种端到端的求解方法来求解结构的响应。在凝聚和非凝聚的一般方程中对各层的位移响应进行了计算,结果清楚地表明了该方法的准确性。数值分析和各种摩擦阻尼结构的模拟结果表明,所提出的方法与商业有限元方法相结合,适用于分析各种类型的结构。值得注意的是,在所提出的方法和传统有限元方法下研究的结构的加速度和位移响应非常一致,仅观察到1.5%的差异。此外,由于在分析过程中正确分配了自由度,这种方法降低了计算成本,尤其是在大型建筑中。
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引用次数: 0
Effect of Glazed Loggias on the Energy Efficiency of a T08b Prefabricated Dwelling – A Case Study 玻璃长廊对T08b装配式住宅能源效率的影响——一个案例研究
IF 0.4 Pub Date : 2021-09-01 DOI: 10.2478/sjce-2021-0020
Roman Ruhig, Ema Ruhigová
Abstract The topic focuses on current solutions of interspaces in the renovation and modernization of residential buildings, the design of which is conditioned by the principles of sustainable development and construction. It concerns the integration of closed interspaces in renovated buildings from the 1950s to the 1980s. One example is the frequent glazing of loggias/balconies in original panel construction. The form of glazing of loggias and balconies is not regulated and is chosen by the apartment owners. For these reasons, the integration of interspaces in renovated buildings should be supported by research that will bring new insights about their effect on assessments of the energy performance of residential buildings and their effect on the architectural expression of facades. The paper compares alternatives for the integration of interspaces with an emphasis on the efferc of their orientation. The research should serve to help regulate the glazing of loggias in residential panel buildings.
摘要本课题的重点是当前住宅建筑翻新和现代化中空间的解决方案,其设计以可持续发展和建设的原则为条件。它涉及20世纪50年代至80年代翻修建筑中封闭空间的整合。一个例子是在原始面板结构中经常为凉廊/阳台上釉。凉廊和阳台的玻璃形式没有规定,由公寓业主选择。出于这些原因,翻新建筑中空间的整合应该得到研究的支持,这些研究将为其对住宅建筑能源性能评估的影响及其对立面建筑表现的影响带来新的见解。本文比较了空间积分的替代方案,并强调了它们的方向传出。这项研究应该有助于规范住宅面板建筑中凉廊的玻璃。
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引用次数: 1
Modelling Pedestrian Crossing Behaviour at a Midblock Section 模拟在街区中段行人过马路的行为
IF 0.4 Pub Date : 2021-09-01 DOI: 10.2478/sjce-2021-0017
Yugendar Poojari, E. Prashanth, D. Divya, M. Kalyani
Abstract In general, pedestrians want to cross a road at a mid-block section instead of intersections because it is the shortest route. According to an Indian scenario, most of the crosswalks in urban areas are not signalised and controlled. In this study, the crossing behaviour of pedestrians in terms of speed at a midblock section was studied by considering several parameters. Statistical tests such as ANOVA and Pearson correlation tests were performed in order to know the effect of parameters on the crossing speed of a pedestrian. The pedestrian’s age and gender, crossing type, pattern, time, number of stops, number of two wheelers, three wheelers, light and heavy commercial vehicles, and groups significantly affect their crossing speed. A multiple linear regression model was developed by considering the most significant parameters. The mean absolute percentage error, root mean square error, and R2 values were calculated to validate the models.
摘要一般来说,行人希望在街区中间路段而不是十字路口过马路,因为这是最短的路线。根据印度的情况,城市地区的大多数人行横道都没有信号和控制。在这项研究中,通过考虑几个参数,研究了街区中段行人的过街行为。为了了解参数对行人过街速度的影响,进行了方差分析和皮尔逊相关检验等统计检验。行人的年龄和性别、过街类型、方式、时间、停车次数、两轮车、三轮车、轻型和重型商用车的数量以及群体显著影响其过街速度。通过考虑最重要的参数,建立了多元线性回归模型。计算平均绝对百分比误差、均方根误差和R2值以验证模型。
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引用次数: 0
Measuring Control Delays at Signalized Intersections in Mixed Traffic Conditions 混合交通条件下信号交叉口控制延误的测量
IF 0.4 Pub Date : 2021-09-01 DOI: 10.2478/sjce-2021-0019
R. Sushmitha, K. Ravishankar
Abstract Control delay is the key performance indicator of a signalized intersection that defines the level of service. Several models have been developed in previous research work for estimating control delays, but many of them were based on homogeneous traffic conditions. In the present study, an Open Street Map (OSM) tracker mobile application was used to measure control delays from the field. A non-linear model was developed in the present study for estimating control delays in mixed traffic conditions using a MATLAB fitting tool. The field delay is compared with the developed non-linear model delay along with the Indian Highway Capacity manual (INDO HCM) and Highway Capacity Manual (HCM) models. The control delay estimated using the model developed in the present study shows a close relation with the field delay obtained using an OSM tracker when compared to that obtained using the INDO HCM and HCM models. Therefore, the OSM tracker mobile application can be used as a field control delay measuring technique.
控制延迟是信号交叉口的关键性能指标,它决定了交叉口的服务水平。在以往的研究工作中,已经建立了几种用于估计控制延迟的模型,但其中许多模型都是基于均匀交通条件的。在本研究中,使用开放街道地图(OSM)跟踪移动应用程序来测量来自现场的控制延迟。本文利用MATLAB拟合工具建立了混合交通条件下的非线性控制延迟估计模型。将现场延迟与已开发的非线性模型延迟以及印度公路容量手册(INDO HCM)和公路容量手册(HCM)模型进行了比较。与使用INDO HCM和HCM模型获得的控制延迟相比,使用本研究中开发的模型估计的控制延迟与使用OSM跟踪器获得的场延迟密切相关。因此,OSM跟踪器移动应用程序可以作为现场控制延迟测量技术。
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引用次数: 3
Comparative analysis of Activated Corn Cob and Bentonite Clay for the Removal of Lead and Nickel from Raw Water 活性玉米芯与膨润土对原水中铅、镍的去除效果比较分析
IF 0.4 Pub Date : 2021-06-01 DOI: 10.2478/sjce-2021-0011
Uchechi Akomah, I. Nwaogazie, O. Akaranta, A. David
Abstract The extensive use of commercial activated carbon as an adsorbent for the purification of industrial effluent is not economical for small and medium-sized enterprises due to its high operational cost. This study was carried out to compare the adsorptive capacity of bentonite clay and activated corn cob (“BC” and “ACC”) for the removal of lead (II) and nickel (II) ions from an aqueous solution. The results obtained from the characterization of the BC and ACC are pH: 7.43 and 6.74; moisture content: 36.45kg/kg and 12.10kg/kg, and bulk density: 1.243g/ml and 1.162g/ml, respectively. Normality tests using the coefficient of skewness indicated that the set of data was not normally distributed. An analysis of variance (ANOVA) test conducted using Friedman’s 2-way ANOVA test indicated p values of 0.0253 against an alpha value of 0.05, which indicates significance. The Friedman results indicated significance with respect to the varied dosages, initial concentrations, and contact time. The effect of the adsorbent was not significant. The adsorption isotherms were analysed using the Langmuir, Freundlich, and Temkin isotherms. Most research studies have shown that adsorption experiments performed using most low-cost materials tend to follow the Freundlich adsorption isotherm, but the results of this experimental study proved that activated corn cob and bentonite clay performed better with the Temkin adsorption isotherm with 0.879 ≤ R2 ≤ 0.917 for the bentonite clay and 0.9572 ≤ R2 ≤ 0.99 for the activated corn cob respectively. The study revealed that these materials are good adsorbents that can be used for the removal of lead (II) and nickel (II) ions from an aqueous solution.
摘要商业活性炭作为吸附剂广泛用于工业废水的净化,由于其操作成本高,对中小型企业来说并不经济。本研究旨在比较膨润土和活性玉米芯(“BC”和“ACC”)对水溶液中铅(II)和镍(II)离子的吸附能力。从BC和ACC的表征中获得的结果是pH:7.43和6.74;水分含量分别为36.45kg/kg和12.10kg/kg,堆积密度分别为1.243g/ml和1.162g/ml。使用偏度系数的正态性测试表明,这组数据不是正态分布的。使用Friedman的双向方差分析检验进行的方差分析(ANOVA)检验显示p值为0.0253,而α值为0.05,这表明显著性。Friedman结果表明,在不同的剂量、初始浓度和接触时间方面具有显著性。吸附剂的作用不显著。使用Langmuir、Freundlich和Temkin等温线分析吸附等温线。大多数研究表明,使用大多数低成本材料进行的吸附实验倾向于遵循Freundlich吸附等温线,但实验结果表明,活性玉米芯和膨润土的Temkin吸附等温线较好,膨润土吸附等温线分别为0.879≤R2≤0.917和0.9572≤R2≤0.99。研究表明,这些材料是很好的吸附剂,可用于从水溶液中去除铅(II)和镍(II)离子。
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引用次数: 2
The Reinforcement of Sand by Fibres with a Non-Uniform Shape 非均匀形状纤维对砂土的加固
IF 0.4 Pub Date : 2021-06-01 DOI: 10.2478/sjce-2021-0013
Pavel Koudela, J. Chalmovský, L. Míča
Abstract The reinforcement of soil is used to improve its strength and stiffness. The standard method of soil reinforcement is an application of geosynthetics. Soil reinforcement by distributed discrete fibres represents an alternative to those techniques. Currently used fibres have a straight shape, uniform cross-section, and smooth surface, which is not optimal in terms of the fibre-soil interaction. In this study, fibres with a variable shape were utilized. The fibres were fabricated using a fused deposition modelling technology. Firstly, a brief theoretical background is presented. Then, the proposed shapes of the fibres and their manufacturing process are described. The mechanical properties of the soil-fibre composite were investigated through consolidated drained triaxial tests. Well-graded coarse sand and poorly-graded fine sand were used. A higher peak shear strength was observed in the case of fibres with a variable shape. The effect of the variable shape of the fibres on the peak shear strength was higher in the case of the coarse sand.
摘要土的加固是为了提高其强度和刚度。土壤加固的标准方法是土工合成材料的应用。分布式离散纤维加固土壤是这些技术的替代方案。目前使用的纤维具有直的形状、均匀的横截面和光滑的表面,这在纤维-土壤相互作用方面不是最佳的。在这项研究中,使用了形状可变的纤维。纤维是使用熔融沉积建模技术制造的。首先,简要介绍了本文的理论背景。然后,介绍了所提出的纤维形状及其制造工艺。通过固结排水三轴试验研究了土纤维复合材料的力学性能。采用级配良好的粗砂和级配较差的细砂。在具有可变形状的纤维的情况下观察到较高的峰值剪切强度。在粗砂的情况下,纤维形状的变化对峰值剪切强度的影响更大。
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引用次数: 0
Effect of Modifying Aggregates by Rap and the Simultaneous use of Adhesives for the Stabilization of a Sandy Pavement Subgrade 振捣改性集料和同时使用胶粘剂对砂质路面路基稳定的影响
IF 0.4 Pub Date : 2021-06-01 DOI: 10.2478/sjce-2021-0008
M. Khabiri, Bahareh Ebrahimialavijeh
Abstract The improvement, reconstruction and repair of roads in recent years have increased the content of recycled asphalt in pavements. Using these materials in road construction projects because they reduce the costs, will also be of great help in improving environmental issues. In the present study, dune sand, which can be found in most desert area soil but does not have proper strength and loading capacity for a subgrade, was used. In order to increase the strength parameters of dune sand, various contents of cement and recycled asphalt were examined in California Bearing Ratio (CBR) and compressive strength tests. The results showed that the addition of cement and recycled asphalt can increase compressive strength and bearing capacity and reduce rupture deformations. In a stabilized sample with 27.5% recycled asphalt, increasing the cement from 7.5 to 12.5% increased the compressive strength by 1.045 times, which is the highest amount of change in the samples studied. The maximum CBR and minimum rupture deformations are related to 35% of the recycled asphalt and 12.5% of the cement. The predicted functions of the compressive strength, deformation and CBR depend on two variables of the cement content; the recycled asphalt was then calculated using the response surface method
摘要近年来,道路的改善、改造和维修,提高了路面中再生沥青的含量。在道路建设项目中使用这些材料,因为它们降低了成本,也将对改善环境问题有很大帮助。在本研究中,使用了沙丘沙,它可以在大多数沙漠地区的土壤中找到,但不具有适当的强度和路基承载能力。为了提高沙丘砂的强度参数,对不同含量的水泥和再生沥青进行了加州承载比和抗压强度试验。结果表明,水泥和再生沥青的掺加可以提高抗压强度和承载力,减少断裂变形。在含有27.5%再生沥青的稳定样品中,将水泥从7.5%增加到12.5%,抗压强度增加了1.045倍,这是所研究样品中变化量最大的。最大CBR和最小断裂变形与35%的再生沥青和12.5%的水泥有关。抗压强度、变形和CBR的预测函数取决于水泥含量这两个变量;然后使用响应面法计算再生沥青
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引用次数: 2
The Domaša Reservoir in the Spectrum of Climate Change 气候变化光谱中的多马沙水库
IF 0.4 Pub Date : 2021-06-01 DOI: 10.2478/sjce-2021-0009
J. Skvarka, E. Bednárová, Marián Miščík, Ľubomír Uhorščák
Abstract The importance of water reservoirs in the uneven distribution of discharges over time and space does not need to be explicitly justified. There is a more than 6,000-year history of convincing evidence. In Slovakia, the construction of reservoirs can be dated to two periods. The first period was the 18th century, when the construction of water reservoirs was stimulated by the need for water for the mining industry in the vicinity of the town of Bánska Štiavnica. The second period falls into the second half of the 20th century. The construction of reservoirs was initiated by the post-war period, including the need to increase society’s standard of living, the electrification of the region, the development of industry and agriculture, flood protection, etc. Reservoirs with multi-annual regulations have an essential position in the types of water reservoirs. While small water reservoirs and annual or seasonal regulation can regulate flows in a short period, reservoirs with multi-annual regulation can regulate flows over several years. This benefit is evident, especially during periods of extreme hydrological phenomena and short-term aquatic and long-term dry, so-called low water periods. We have illustrated our knowledge of and experience gained from their impact on the flows downstream of the Veľká Domaša dam. We analyzed two time periods, i.e., before and after the year 2000. The influence of extreme hydrological phenomena on the runoff conditions downstream of the dam is presented by statistical processing of the available flow series
摘要水库在流量随时间和空间的不均匀分布中的重要性无需明确证明。有6000多年的令人信服的证据。在斯洛伐克,水库的建设可以追溯到两个时期。第一个时期是18世纪,当时由于对BánskaŠtiavnica镇附近采矿业用水的需求,水库的建设受到了刺激。第二个时期是20世纪下半叶。水库的建设始于战后时期,包括提高社会生活水平的需要、地区的电气化、工农业的发展、防洪等。多年制水库在水库类型中占有重要地位。小型水库和年度或季节性调节可以在短时间内调节流量,而多年调节的水库可以在几年内调节流量。这种好处是显而易见的,尤其是在极端水文现象和短期水生和长期干旱的时期,即所谓的枯水期。我们已经说明了我们对其对VeľkáDomaša大坝下游流量影响的了解和经验。我们分析了两个时间段,即2000年之前和之后。通过对可用流量序列的统计处理,给出了极端水文现象对大坝下游径流条件的影响
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引用次数: 1
期刊
Slovak Journal of Civil Engineering
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