大型布袋钢结构除尘器有限元分析

在合理简化的基础上,运用非线性有限元软件ABAQUS建立了大型布袋除尘器钢结构的有限元模型,分析结构在6种工况组合下的应力及变形,结果均满足设计要求.针对钢仓筒的有限元建模方法是合理的,可以应用于实际工程,并对同类结构设计有一定参考价值.     

大跨度桥梁0~#块水化热分析

文章以巴河特大桥0~#块为例,介绍大跨度桥梁0~#块水化热分析,详细介绍水化热分析参数的选取以及有限元模型的建立。有限元计算结果表明本桥0#块水化热满足规范要求。并将有限元分析结果与现场实测结果进行了对比,对比结果表明,有限元分析结果与现场实测结果规律相近,现场实测温度比有限元略大,两种误差在合理范围内,说明有限元模型及分析参数是合理的,可为类似工程分析和施工提供借鉴。     

空心钢管混凝土轴压短柱的有限元分析

在轴压试验结果的基础上,选择合理的材料本构关系模型,应用有限元软件ABAQUS对空心圆钢管混凝土短柱进行了有限元模拟,着重讨论了有限元模型的建立方法,并通过模拟结果与试验结果的对比验证了有限元模型的合理性。     

碳纤维加固混凝土梁的有限元分析

运用有限元分析软件ANSYS建立了CFRP抗弯加固梁的有限元分析模型,与试验结果对比,有限元计算值与试验结果吻合较好,建立的CFRP抗弯加固梁有限元模型较为合理。     

多边形空心钢管混凝土轴压短柱非线性分析

在轴压试验结果的基础上,选择合理的材料本构关系模型,应用大型通用ANSYS有限元软件对四边形和八边形空心钢管混凝土短柱进行了有限元模拟,着重讨论了有限元模型的建立方法,并通过模拟结果与试验结果的对比,验证了有限元模型的合理性。     

利用ANSYS分析软土地区桥台

针对软土地区的桥台,引用Solid65单元建立了桥台-桩基系统分析模型,进行了有限元计算,结果表明,在准确建立有限元模型并合理选择材料类型的前提下,利用ANSYS可以合理地解释该桥台的开裂现象,为桥台加固提供理论指导.     

基于有限元的钢筋混凝土空心板受力性能分析

本文使用大型有限元软件ANSYS对钢筋混凝土圆管空心板进行非线性有限元数值模拟研究,得出空心板在设计荷载作用下应力分布规律及裂纹情况。通过非线性有限元方法分析研究现浇钢筋混凝土圆管空心板的基本力学性能,探索其合理的计算模式。     

文克勒地基在矩形水池有限元分析中的合理应用

针对文克勒地基模型应用于水池结构有限元计算中的一些不合理认识,通过力学模型的分析以及有限元对具体水池结构的复核验算,指出水池结构采用文克勒地基模型进行有限元计算时必须设置合理的边界条件,合理的边界条件必须满足水池结构和地基的变形、地基反力分布与实际趋势相似;对底板四个角点施加不动铰支座是一种合理的边界约束条件;同时底板作为壁板固结支承的模式也是一种能满足工程精度要求的合理简化模式。     

某钢管混凝土拱桥合理成桥状态的确定

在钢管拱桥的设计中,桥梁的合理成桥状态的确定是设计的首要任务.合理成桥状态确定是静力分析的首要环节.本文采用有限元软件Midas Civil建立其有限元模型,并利用斜拉桥的索力理论及调整方法,通过比较确定了吊杆拱桥的合理成桥状态的方法-刚性吊杆法的结论.     

逆作法施工预留反压土的作用效应分析

介绍了逆作法预留反压土效应分析所采用的基本理论,给出了预留土体的土压力分布、支护桩的刚度矩阵和弹性杆件有限元的刚度矩阵,在此基础上可编制分析程序。将计算结果与有限元软件分析结果进行对比,两者误差在合理范围内,说明本方法原理恰当、便于使用且结果合理。     

On the design of Web-tapered,unequal-flanged structural steel columns

A study directed towards the development of an efficient and economical design for stability of structural steel members is described. A finite element method is presented for determining the lateral-torsional buckling load for linearly tapered I-section members with unequal flange areas. Solutions are obtained for different flange-area ratios and tapering ratios. Such solutions are used to develop an interaction relationship for tapered unequal-flanged steel structural colums subjected to both axial and bending stresses.The formulation is intended to provide a more rational approach to the design of tapered steel columns—a step towards an optimum stability design for structural steel members.     

泰州火车站无站台柱大跨拱形钢雨棚结构设计

江苏泰州市火车站大跨拱形钢雨棚为无站台柱雨棚,大跨度雨棚主体结构采用钢管混凝土柱与空间倒三角钢管桁架,为风敏感体系。通过风洞试验和风振分析确定工程设计参数,采用三维有限元模型进行内力分析,包括温度作用和水平推力对超长大跨拱形结构的影响,并对结构的整体稳定性进行分析,同时采用合理的支撑体系保证结构的整体刚度。     

Nonlinear behaviour of unprotected composite slim floor steel beams exposed to different fire conditions

An efficient nonlinear 3D finite element model has been developed to investigate the structural performance of composite slim floor steel beams with deep profiled steel decking under fire conditions. The composite steel beams were unprotected simply supported with different cross-sectional dimensions, structural steel sections, load ratios during fire and were subjected to different fire scenarios. The nonlinear material properties of steel, composite slim concrete floor and reinforcement bars were incorporated in the model at ambient and elevated temperatures. The interface between the structural steel section and composite slim concrete floor was also considered, allowing the bond behaviour to be modelled and the different components to retain its profile during the deformation of the composite beam. Furthermore the thermal properties of the interface were included in the finite element analysis. The finite element model has been validated against published fire tests on unprotected composite slim floor steel beams. The time–temperature relationships, deformed shapes at failure, time–vertical displacement relationships, failure modes and fire resistances of the composite steel beams were evaluated by the finite element model. Comparisons between predicted behaviour and that recorded in fire tests have shown that the finite element model can accurately predict the behaviour of the composite steel beams under fire conditions. Furthermore, the variables that influence the fire resistance and behaviour of the unprotected composite slim floor steel beams, comprising different load ratios during fire, cross-section geometries, beam length and fire scenarios, were investigated in parametric studies. It is shown that the failure of the composite beams under fire conditions occurred for the standard fire curve, but did not occur for the natural fires. The use of high strength structural steel considerably limited the vertical displacements after fire exposure. It is also shown that presence of additional top reinforcement mesh is necessary for composite beams exposed to short hot natural fires. The fire resistances of the composite beams obtained from the finite element analyses were compared with the design values obtained from the Eurocode 4 for composite beams at elevated temperatures. It is shown that the EC4 predictions are generally conservative for the design of composite slim floor steel beams heated using different fire scenarios.     

Numerical study of built-up double-Z members in bending and compression

The use of the finite element method (FEM) for the design of composed, thin-walled, structural steel members is considered. The bolted double-Z frame member is an interesting and economical engineering solution, already used in practice [1]. However, the European recommendations for the design of steel structures do not consider built-up members from cold-formed steel profiles. Finite element analysis is used to capture the various buckling effects that shape the response of slender thin-walled members. From the finite element model, the importance of initial imperfections and stiffness of connections is identified. The experimentally validated model predictions show that a non-linear finite element analysis can predict the member behaviour, in terms of failure mode and ultimate load, yield line pattern, overall stiffness and local strain in the cold-formed profiles. To obtain a good prediction, overall and localised initial imperfections should be considered and included in the analysis.     

Design of cold-formed steel unequal angle compression members

Cold-formed steel unequal angles are non-symmetric sections. The design procedure of non-symmetric sections subjected to axial compression load could be quite difficult. The unequal angle columns may fail by different buckling modes, such as local, flexural and flexural–torsional buckling as well as interaction of these buckling modes. The purpose of this study is to investigate the behaviour and design of cold-formed steel unequal angle columns. A nonlinear finite element analysis was conducted to investigate the strength and behaviour of unequal angle columns. The measured initial local and overall geometric imperfections as well as the material properties of the angle specimens were included in the finite element model. The finite element analysis was performed on fixed-ended columns for different lengths ranged from stub to long columns. It is demonstrated that the finite element model closely predicted the experimental ultimate loads and the behaviour of cold-formed steel unequal angle columns. Hence, the model was used for an extensive parametric study of cross-section geometries. The column strengths obtained from the parametric study were compared with the design strengths calculated using the North American Specification for cold-formed steel structural members. It is shown that the current design rules are generally unconservative for short and intermediate column lengths for the unequal angles. Therefore, design rules of cold-formed steel unequal angle columns are proposed.     

Strength and post‐yield behavior of T‐section steel encased by structural concrete

In this study, the seismic performance of unsymmetrical steel–concrete composite precast beams with T‐shaped steel section were numerically explored and validated by their earlier experimental investigation. This design is based on the proposed calibrated finite element model in which key damage parameters for the evaluation of the nonlinear, post‐yield behavior of the precast composite steel beams were identified. The proposed nonlinear finite‐element‐based numerical model uses various parameters, including the dilatation angle and concrete‐damaged plasticity, to simulate the nonlinear behavior of unsymmetrical composite precast beams with T‐section steel. Greater seismic capacity with greater ductility, contributing to a maximized structural capacity within the composite precast beams was introduced by the effective use of the 2 materials, steel and concrete, and shown by the nonlinear hysteretic investigation of unsymmetrical steel–concrete composite precast beams that was validated experimentally. The post‐yield structural capacity found via the numerical analysis agrees with experimental results when the concrete‐damaged plasticity of the plastic‐damaged seismic model for concrete and the von Mises criteria of the steel section were introduced into the finite element model. Practical design parameters and recommendations were eventually suggested by examining the influence of precast composite beams with unsymmetrical steel sections on the concrete degradations and damage evolution.     

Structural performance of cold-formed high strength stainless steel columns

This paper describes an accurate finite element model for the structural performance of cold-formed high strength stainless steel columns. The finite element analysis was conducted on duplex stainless steel columns having square and rectangular hollow sections. The columns were compressed between fixed ends at different column lengths. The effects of initial local and overall geometric imperfections have been taken into consideration in the finite element model. The material nonlinearity of the flat and corner portions of the high strength stainless steel sections were carefully incorporated in the model. The column strengths and failure modes as well as the load-shortening curves of the columns were obtained using the finite element model. Furthermore, the effect of residual stresses in the columns was studied. The nonlinear finite element model was verified against experimental results. An extensive parametric study was carried out using the verified finite element model to study the effects of cross-section geometries on the strength and behaviour of cold-formed high strength stainless steel columns. The column strengths predicted from the parametric study were compared with the design strengths calculated using the American Specification, Australian/New Zealand Standard and European Code for cold-formed stainless steel structures. The results of the parametric study showed that the design rules specified in the American, Australian/New Zealand and European specifications are generally conservative for cold-formed high strength stainless steel square and rectangular hollow section columns, but unconservative for some of the short columns.     

新型轻钢龙骨体系水平位移有限元分析方法

无比钢结构是一种新型的轻钢龙骨体系,我国现有的结构软件无法直接对其进行设计和计算,采用有限元方法是目前进行结构分析较好的选择。介绍了无比钢结构的组成及做法,提出了整体结构的有限元建模方法,并以5层教学楼为例,采用ABAQUS软件包分析了结构在风载和地震荷载作用下的水平位移,且与规范要求的最大值进行了比较。结果表明,按所提出的针对无比钢结构的有限元建模和分析方法,在风载和地震作用下计算得到的多层无比钢结构的层间和顶点水平位移均可以满足规范要求。     

Q460高强钢焊接箱形截面轴压构件整体稳定性能研究

为研究高强度钢材轴心受压钢柱的整体稳定性能,对5个国产Q460钢材焊接箱形截面柱进行了轴心受压试验研究。试验对试件的几何初弯曲、荷载初偏心以及截面的纵向残余应力分布均进行了测量。基于试验结果,分析了该类钢柱的失稳破坏形态和整体稳定承载力,建立了有限元分析模型并对试验结果进行模拟计算。研究结果表明：试件破坏模态均为整体弯曲失稳形态,大部分试件稳定承载力高于规范设计值;有限元分析模型能够准确地考虑几何初始缺陷和残余应力的影响,计算结果与试验结果吻合良好;通过与国内外钢结构设计规范的对比,提出了国产Q460高强钢焊接箱形截面轴压构件整体稳定设计的建议方法,即可以统一采用我国或欧洲规范的b类曲线进行设计,而不需要按板件宽厚比大小进行分类。     

Structural performance of cold-formed lean duplex stainless steel columns

The structural performance of cold-formed lean duplex stainless steel columns was investigated. A wide range of finite element analysis on square and rectangular hollow sections and other available data, with a total number of 259 specimens, were considered. An accurate finite element model has been created to simulate the pin-ended cold-formed lean duplex stainless steel columns. Extensive parametric study was carried out using the validated finite element model. The column strengths predicted from the parametric study together with the available data are compared with the design strengths calculated from various existing design rules for cold-formed stainless steel structures. It is shown that the existing design rules, except for the ASCE Specification as well as the stub column and full area approach, are conservative. Modifications are proposed for the AS/NZS Standard, EC3 Code, and direct strength method. Reliability analysis was performed to assess the existing and modified design rules. It is also shown that the modified design rules are able to provide a more accurate and reliable predictions for lean duplex stainless steel columns. In this study, it is suggested that the modified design rules in the AS/NZS Standard and the modified direct strength method to be used in designing cold-formed lean duplex stainless steel columns.