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FE modeling of concrete Beams and columns reinforced with FRP composites

Defence Technology（防务技术） 2021年第1期17卷 1-14页

作者： Farid Abed Chahmi Oucif Yousef Awera Haya H.Mhanna Hakem Alkhraisha Department of Civil Engineering American University of SharjahP.O.Box 26666United Arab Emirates Institute of Structural Mechanics(ISM) Bauhaus-Universitat WeimarMarienstraße 15D-99423WeimarGermany

Compression and flexure members such as columns and Beams are critical in a structure as its failure could lead to the collapse of the structure.In the present work,numerical analysis of square and circle short columns,and reinforced concrete(RC)Beams reinforced with fiber reinforced polymer composites are carried out.This work is divided into two parts.In the first part,numerical study of axial behavior of square and circular concrete columns reinforced with Glass Fiber Reinforced Polymer(GFRP)and Basalt Fiber Reinforced Polymer(BFRP)bars and spiral,and Carbon Fiber Reinforced Polymer(CFRP)wraps is conducted.The results of the first part showed that the axial capacity of the circular RC columns reinforced with GFRP increases with the increase of the longitudinal reinforcement ratio.In addition,the results of the numerical analysis showed good correlation with the experimental ones.An interaction diagram for BFRP RC columns is also developed with considering various eccentricities.The results of numerical modeling of RC columns strengthened with CFRP wraps revealed that the number and the spacing between the CFRP wraps provide different levels of ductility enhancement to the column.For the cases considered in this study,column with two middle closely spaced CFRP wraps demonstrated the best performance.In the second part of this research,flexural behavior of RC Beams reinforced with BFRP,GFRP and CFRP bars is investigated along with validation of the numerical model with the experimental tests.The results resembled the experimental observations that indicate significant effect of the FRP bar diameter and type ont he flexural capacity of the RC Beams.It was also shown that Increasing the number of bars while keeping the same reinforcement ratio enhanced the stiffness of the RC beam.

关键词： Numerical analysis BRFP GFRP CFRP Columns Beams Experimental tests

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Inverse Optimal Control of Evolution Systems and Its Application to Extensible and Shearable Slender Beams

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IEEE/CAA Journal of Automatica Sinica 2019年第2期6卷 395-409页

作者： K.D.Do A.D.Lucey the Department of Mechanical Engineering Curtin University

An optimal(practical) stabilization problem is formulated in an inverse approach and solved for nonlinear evolution systems in Hilbert spaces. The optimal control design ensures global well-posedness and global practical K∞-exponential stability of the closed-loop system, minimizes a cost functional,which appropriately penalizes both state and control in the sense that it is positive definite(and radially unbounded) in the state and control, without having to solve a Hamilton-Jacobi-Belman equation(HJBE). The Lyapunov functional used in the control design explicitly solves a family of HJBEs. The results are applied to design inverse optimal boundary stabilization control laws for extensible and shearable slender Beams governed by fully nonlinear partial differential equations.

关键词： Boundary control evolution system Hilbert space inverse optimal control slender Beams

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Predicting the response of continuous RC deep Beams under varying levels of differential settlement

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Frontiers of Structural and Civil Engineering 2019年第3期13卷 686-700页

作者： M.Z.NASER R.A.HAWILEH Glenn Department of Civil Engineering Clemson UniversityClemsonSC 29634USA Department of Civil Engineering American University of SharjahSharjahUnited Arab Emirates Materials Science and Engineering Research Institute American University of SharjahSharjahUnited Arab Emirates

This paper investigates the effect of differential support settlement on shear strength and behavior of continuous reinforced concrete(RC)deep Beams.A total of twenty three-dimensional nonlinear finite element models were developed taking into account various constitutive laws for concrete material in compression(crushing)and tension(cracking),steel plasticity(i.e.,yielding and strain hardening),bond-slip at the concrete and steel reinforcement interface as well as unique behavior of spring-like support elements.These models are first validated by comparing numerical predictions in terms of load-deflection response,crack propagation,reaction distribution,and failure mode against that of measured experimental data reported in literature.Once the developed models were successfully validated,a parametric study was designed and performed.This parametric study examined number of critical parameters such as ratio and spacing of the longitudinal and vertical reinforcement,compressive and tensile strength of concrete,as well as degree(stiffness)and location of support stiffness to induce varying levels of differential settlement.This study also aims at presenting a numerical approach using finite element simulation,supplemented with coherent assumptions,such that engineers,practitioners,and researchers can carry out simple,but yet effective and realistic analysis of RC structural members undergoing differential settlements due to variety of load actions.

关键词： concrete continuous Beams deep Beams finite element modeling support settlement

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Investigation on modeling parameters of concrete Beams reinforced with basalt FRP bars

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Frontiers of Structural and Civil Engineering 2019年第6期13卷 1520-1530页

作者： Jordan CARTER Aikaterini S.GENIKOMSOU Civil Engineering Department Queen s UniversityKingstonON K7N 3N6Canada

Fiber-reinforced polymer(FRP)bars are widely used as internal reinforcement replacing the conventional steel bars to prevent from corrosion.Among the different types of FRP bars,basalt FRP(BFRP)bars have been used in different structural applications and,herein,three already tested concrete Beams reinforced with BFRP bars are analyzed using three-dimensional(3-D)finite element analysis(FEA).The Beams were tested in four-point bending.In the FEA the behavior of concrete is simulated using the^Concrete-Damaged Plasticity^^model offered in ABAQUS software.The research presented here presents a calibrated model for nonlinear FEA of BFRP concrete Beams to predict their response considering both the accuracy and the computational efficiency.The calibration process showed that the concrete model should be regularized using a mesh-dependent characteristic length and material-dependent post-yield fracture and crushing energies to provide accurate mesh-size independent results.FEA results were compared to the test results with regard to failure load and crack patterns.Both the test results and the numerical results were compared to the design predictions of ACI 440.1R-15 and CSA S806-12,where CSA S806-12 seems to overestimate the shear strength for two Beams.

关键词： basalt Fiber-reinforced polymer bars reinforced concrete Beams finite element analysis damaged plasticity model design codes

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Behavior of reinforced concrete Beams and columns subjected to blast loading

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Defence Technology（防务技术） 2018年第5期14卷 550-559页

作者： Yan Liu Jun-bo Yan Feng-lei Huang State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology

In this study, the blast performance of steel reinforced concrete(RC) Beams was experimentally and analytically investigated. The experiment consists of a total of 10 one-half-scale Beams subjected to different levels of blast loading using live explosives. The reflected pressure-time histories were recorded and different damage levels and modes were observed. The blast resilience of the damaged Beams was quantified by measuring the time-dependent displacements. Experiment results show that the damage in steel reinforced concrete Beams with higher explosive mass is enhanced compared with that of the Beams with smaller explosive mass at the same scaled distance. Based on the experiment data, an empirical expression is developed via dimensional analysis to correct the relationship between the midspan displacement and scaled distance. Besides, a complex single degree of freedom model(SDOF)incorporating complex features of the material behavior, high strain-rate effect and the column geometry was proposed and validated by test results.

关键词： Blast Steel reinforced concrete Beams Dynamic response Scaling SDOF

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Active vibration control of functionally graded Beams with piezoelectric layers based on higher order shear deformation theory

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Earthquake Engineering and Engineering Vibration 2016年第4期15卷 611-620页

作者： K. Bendine F.B. Boukhoulda M.Nouarit Z. Satla Mechanics of Structures and Solids Laboratory Department of Mechanics Faculty of technology Djillali Liabes University of Sidi Bel-Abbes Algeria University of Lorraine Laboratoire d'Energetique et de Mecanique Theorique et Appliquee LEMTA CNRS-UMR 7563 Mines Nancy Nancy 88100 France

This paper reports on a study of active vibration control of functionally graded Beams with upper and lower surface-bonded piezoelectric layers. The model is based on higher-order shear deformation theory and implemented using the finite element method （FEM）. The proprieties of the functionally graded beam （FGB） are graded along the thickness direction. The piezoelectric actuator provides a damping effect on the FGB by means of a velocity feedback control algorithm. A Matlab program has been developed for the FGB model and compared with ANSYS APDL. Using Newmark＇s method numerical solutions are obtained for the dynamic equations of FGB with piezoelectric layers. Numerical results show the effects of the constituent volume fraction and the influence the feedback control gain on the frequency and dynamic response of FGBs.

关键词： Beams piezoelectric finite element method functionally graded materials vibration control

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地图自动综合中Beams移位算法的实现与改进

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武汉大学学报（信息科学版） 2016年第4期41卷 450-454,540页

作者：刘远刚郭庆胜孙雅庚杨乃郑春燕武汉大学资源与环境科学学院湖北武汉430079 长江大学地球科学学院湖北武汉430100 武汉大学测绘遥感信息工程国家重点实验室湖北武汉430079 中国地质大学(武汉)信息工程学院湖北武汉430074 嘉应学院地理科学与旅游学院广东梅州514015

地图自动综合中,基于Beams模型的全局最优化移位算法通过借鉴材料力学中杆件结构的移位和变形,模拟地图上空间目标(群)在移位操作中的传递性和衰减性,从而较好地保持地图目标(群)的形状、空间关系和分布模式。然而,目前对该算法实现细... 详细信息

地图自动综合中,基于Beams模型的全局最优化移位算法通过借鉴材料力学中杆件结构的移位和变形,模拟地图上空间目标(群)在移位操作中的传递性和衰减性,从而较好地保持地图目标(群)的形状、空间关系和分布模式。然而,目前对该算法实现细节的介绍仍然较少,也没有可操作的参数(弹性模量、横截面积和惯性力矩)设置方法。针对此种情况,对算法进行了实现与改进。首先,介绍了算法的基本数学模型与有限元求解方法;然后,从算法实现的角度,详细研究了Beams模型刚度矩阵和外力向量的计算和聚合等关键问题;最后,在降低参数复杂性的前提下,提出了一种自适应参数设置方法来改进算法。为了验证算法的可行性和适用性,在Delaunay三角网的支持下,分别对道路网和建筑物群进行移位,结果表明改进后的算法可较好地应用于地图上线状目标(群)和离散面状目标群的移位。

关键词：地图综合移位 Beams 有限元 Delaunay三角网邻近图

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Stresses of orthotropic laminated Beams subjected to high temperature and mechanical load

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Theoretical & Applied Mechanics Letters 2019年第5期9卷 279-284,I0003页

作者： Zhong Zhang Ding Zhou Xiuli Xu Xuehong Li College of Civil Engineering Nanjing Tech University

Thermo-elastic analysis of simply-supported orthotropic laminated Beams subjected to high temperature and mechanical load is presented on the basis of the exact two-dimensional thermoelasticity theory.The beam is composed of several orthotropic layers,each with temperaturedependent material properties.The governing equation for each layer is analytically solved using the state space method.The displacement and stress solutions of the beam are obtained using the transfer-matrix method.A numerical example is included to study the effects of temperature on the mechanical responses of a sandwich beam.The results reveal two main effects of temperature:(i)inducing deformations and stresses by itself;(ii)affecting the deformations and stresses induced by the mechanical load.

关键词： Orthotropic laminated Beams Temperature-dependent material properties Thermo-elasticity theory State space method Transfer-matrix method

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Heating of multi-species upflowing ion Beams observed by Cluster on March 28, 2001

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Earth and Planetary Physics 2019年第3期3卷 204-211页

作者： FangBo Yu SuiYan Fu WeiJie Sun XuZhi Zhou Lun Xie Han Liu Duo Zhao ShaoJie Zhao Li Li JingWen Zhang Tong Wu Ying Xiong School of Earth and Space Sciences Peking University Department of Climate and Space Sciences and Engineering University of Michigan

Cluster satellites observed three successive outflowing ion Beams on 28 March, 2001. It is generally accepted that these ion Beams, composed of H^+, He^+, and O^+ ions, with three inverted-V structures in their energy spectra, are produced by acceleration through U-shaped potential structures. By eliminating the background ion population and employing Maxwelling fitting, we find that ions coming from the center of the potential structure have higher temperature than those from the flanks. Higher temperature of O^+ and He+compared to that of H^+ indicates that heavy ions are preferentially heated; we further infer that the heating efficiencies of O^+ and He^+ ions differ between the center and edges of the U-shaped potential structures. Estimation based on pitch angle observations shows that heating may also occur at an altitude above the upper boundary of the auroral acceleration region(AAR), where these Beams are generally thought to be formed.

关键词： oxygen ion Beams inverted-V structures U-shaped potential drop preferentially heated heavy ions heating above AAR

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电磁-高斯谢尔模型阵列光束在大气湍流中的传输特性

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光电子．激光 2018年第9期29卷 1031-1038页

作者：张笔灵徐勇根但有全邓学儒赵正权黄永平西华大学理学院四川成都610039 中国民航飞行学院物理教研室四川广汉618307 宜宾学院物理与电子工程学院四川宜宾644007

根据广义惠更斯菲涅尔原理与维格纳分布函数相结合的方法,导出了电磁高斯谢尔模型阵列光束(EGSMA Beams)在大气湍流中传输的均方根空间扩展、角扩展以及M^2因子的解析式。(分析了其传输特性与光束宽度、初始相干长度、阵列光束数量、初... 详细信息

根据广义惠更斯菲涅尔原理与维格纳分布函数相结合的方法,导出了电磁高斯谢尔模型阵列光束(EGSMA Beams)在大气湍流中传输的均方根空间扩展、角扩展以及M^2因子的解析式。(分析了其传输特性与光束宽度、初始相干长度、阵列光束数量、初始偏振度、湍流内尺度以及折射率结构常数的关系。)研究结果表明相对M^2因子随初始偏振度、初始相干长度和折射率结构常数的减小,以及阵列光束数量、光束宽度、和湍流内尺度的增大而减小,此时相对M^2因子受大气湍流影响更小。当经过大约5km的传输距离后,初始相干长度对相对M^2因子的影响开始明显加大,且随传输距离增大而增大。同时研究结果表明当阵列光束数量增加越多时,相对M^2因子越接近1。并且分析得出初始偏振度以及折射率结构常数对相对M^2因子的影响大于相对均方根空间扩展和角扩展。

关键词：大气湍流 EGSMA Beams 二阶矩 M^2因子

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