Beam and shell element model for advanced analysis of steel structural members

Plastic zone method of advanced analysis, which uses shell elements to model the entire structure, is the most accurate method available to predict the ultimate strength and behavior of steel frames. The disadvantage of such full shell plastic zone models is that it is computationally expensive and hence its use is limited to small structures. Beam elements in commercial finite element packages can model residual stress and capture spread of plasticity, but cannot model local buckling of plates that the member is made up of, which leads to unloading and failure in steel frames. A hybrid model using shell elements only in the regions vulnerable to elastic or inelastic local buckling and beam elements in other locations could overcome this limitation of full beam element model. The issues in using this hybrid model are, knowing a priori the location and length of the shell element region and connecting the beam and shell regions without any artificial stress concentrations or incompatible displacements. In this study, in addition to addressing these issues, the hybrid model is systematically evaluated by studying its performance in structural elements. It is seen that the hybrid model strength predictions has an average error of only 0.91% but requires on an average 83% less computational time when compared to the full shell plastic zone models.     

A finite element analysis model for the behaviour of cold-formed steel members

A finite element analysis model for the post-local buckling behaviour of cold-formed steel (CFS) members subjected to axial compression has been developed. The finite element model consists of a Total Lagrangian nonlinear 9-node “assumed strain” shell finite element, and experimental-based material properties models to represent the body of the CFS sections. Experimentally derived residual stress variations, and initial geometric imperfections have also been incorporated. A special loading technique and a displacement solution algorithm were employed to obtain a uniform displacement condition at the loading edges. Details of a test program involving 20 non-perforated, and perforated cold-formed stub-column steel sections have been presented in the second part of the paper. The comparison between the test results, and the finite element results was performed for axial and lateral displacement behaviour, buckling loads, ultimate loads, and axial stress distribution. The comparison forms the basis for the evaluation of the efficiency, and the accuracy of the finite element model, and it indicated that the finite element analysis model constructed herein gives accurate and consistent results for the behaviour of the cold-formed steel members subjected to axial compression.     

转动裂缝模型在钢筋混凝土构件非线性剪切分析中的应用

基于钢筋混凝土转动裂缝模型,应用平面膜单元对钢筋混凝土构件进行全过程非线性剪切分析。通过选择材料单轴本构、总结复杂的平面应力状态、归纳三种主应变空间下的主应变状态及其刚度矩阵共轭项计算方法,改善平面膜单元在有限元分析中的数值稳定性。选取弯-剪作用下钢筋混凝土梁与压-弯-剪作用下剪力墙试验建立有限元模型进行对比验证,试验实测与有限元分析结果吻合良好。对比结果表明,全面细致地考虑可能出现的各种应力状态,依据三种主应变空间下的主应变状态及其刚度矩阵计算方法,可以得到较好的有限元分析的数值稳定性和精度,基于转动裂缝模型的平面膜单元为压-弯-剪作用下的钢筋混凝土构件的全过程非线性分析提供了有效的分析途径。     

Beam tests of composite steel-concrete members: A three-dimensional finite element model

Modern construction makes frequent use of composite steel-concrete beams for bridge and building applications. This paper describes a three-dimensional finite element model in which all components forming the composite member are modelled by means of solid elements. The proposed approach is developed using the commercial software Abaqus and is able to model the composite response without requiring information from push-out tests commonly performed to define the constitutive relationship for the shear connectors. All materials are assumed to behave in a nonlinear fashion. Contact between the elements is simulated using surface-to-surface and embedment techniques. The adequacy and accuracy of the proposed modelling approach are validated against experimental results available in the literature on simply-supported and continuous beam tests with both solid and composite slabs.     

Beam-column element for non-linear dynamic analysis of steel members subjected to blast loading

This paper addresses an innovative semi-analytical non-discretisation numerical methodology for the non-linear dynamic analysis of steel beam-column elements subjected to loading produced by an explosion. For the mechanical-based formulation, the steel beam-column member is modelled as being restrained at its ends by translational and counterpart rotational springs which simulate semi-rigid joints in a frame. The modelling of the cross-section as comprising of elastic and inelastic domains allows for the spread of yielding to be modelled accurately, whilst the effects of large displacements and the rate-dependent effect of steel material due to rapid dynamic loading is taken into account. The generic steel beam-column element that is developed is shown to agree well with solutions given by finite element modelling using ABAQUS, while providing a computationally superior formulation to that of commercial finite element packages. In addition, it provides a more efficacious formulation to those of conventional plastic zone and plastic hinge methods, while it has the potential to be used as a platform for structural analysis and design in which scenarios of progressive collapse are important.     

基于STAAD PRO的钢煤斗有限元三维计算分析

本文对钢煤斗的平面计算方法和空间有限元计算方法作了比较,利用Staadpro软件对钢煤斗的应力、变形、支座反力进行了计算分析,并进一步利用软件计算数据分析钢煤斗壁板厚度和加劲肋间距对煤斗应力和变形的影响,以及对堵煤的不利工况进行了初步分析和探讨。     

某钢结构人行天桥动力特性测试及有限元分析

对一振动较大的人行天桥进行了动力实测,利用有限元分析软件SAP2000建立该结构的有限元模型,利用基于实测数据的频谱分析以及模态分析的方法对其出现的振动问题进行分析,确定结构振动水平,并为同类结构的动力特性研究提供参考。此外,还从通行行人和通行车辆这两个因素对该天桥侧向振动过大的原因进行了深入分析,从而找到了造成该天桥产生实测振动特性的主要原因,对结构出现过大侧向振动给出了合理解释。     

钢框架结构构件选型比较

通过钢框架结构的楼板形式和钢柱截面形式选型对比,指出对于面积不大,功能要求不苛刻的建筑宜优先采用压型钢板楼板和工字形柱,十字形柱;对于规模较大,层高要求严,功能较复杂的建筑,宜优先选用钢筋桁架板和箱形柱。     

外包FRP壳钢筋混凝土梁的有限元分析

对外包FRP壳钢筋混凝土梁进行了有限元分析,并与试验结果进行对比分析,结果表明,有限元方法可较好的预测外包FRP壳钢筋混凝土梁的整体力学性能,但在荷载较大时,计算值与试验值偏差较大。     

Lateral stabilization by steel sheeting of structural members

Although the European Recommendations for the Stressed Skin Design of Steel Structures treat in a quite complete way the collaboration of the sheeting with the whole structure, they do nevertheless not deal with the stabilization by sheeting of individual members (such as rafters or columns) of the framework. This problem is dealt with in the present paper: several formulae have been derived for the calculation of the interaction forces between stabilized members and their sheeting, according to the requirements of the EUROCODE 3.     

Buckling analysis of thin-walled cold-formed steel structural members using complex finite strip method

In this paper, a generalised complex finite strip method is proposed for buckling analysis of thin-walled cold-formed steel structures. The main advantage of this method over the ordinary finite strip method is that it can handle the shear effects due to the use of complex functions. In addition, distortional buckling as well as all other buckling modes of cold-formed steel sections like local and global modes can be investigated by the suggested complex finite strip method. A combination of general loading including bending, compression, shear and transverse compression forces is considered in the analytical model. For validation purposes, the results are compared with those obtained by the Generalized Beam Theory analysis. In order to illustrate the capabilities of complex finite strip method in modelling the buckling behavior of cold-formed steel structures, a number of case studies with different applications are presented. The studies are on both stiffened and unstiffened cold-formed steel members.     

带加劲冷弯薄壁型钢C形受弯构件有限元分析

采用有限元程序ANSYS,对带加劲肋的冷弯薄壁型钢C形截面受弯构件在纯弯和非纯弯两种受弯状态下的力学性能进行了有限元分析,分析结果表明:构件的卷边宽度是影响试件屈曲模式的重要因素,不同的屈曲模式在纯弯与非纯弯的条件下对极限承载力的影响不尽相同。     

钢框架梁抗火分析有限元模型的建立

介绍了应用有限元法进行钢框架梁抗大设计研究时有限元模型的建立，简述了所研究问题的必要性，总结出将工字钢上下翼缘及中间腹板的实际温度加到模型中去的技巧。     

钢结构防火措施的对比分析

介绍钢结构应用技术在国内外的应用及其面临的防火挑战,在例举钢结构几种防火措施的基础上,对比分析各种防火措施的优缺点,最终提出性能化防火设计是必然趋势。     

The structural safety of hollow concrete-filled circular steel members

The resistance of new type of hollow concrete-filled circular steel tubular members under axial compression is considered. The effect of interaction between steel tube and spun concrete core contact surfaces on composite member compressive strength is analysed. The experimental values of member’s resistance and its mechanical model uncertainty are presented. The necessity to assess the structural safety of precast members exposed to actions in pre-use and use working lives is discussed. Peculiarities of the mechanical model describing the safety margin of ageing and not ageing compression members are analysed. The probability-based assessment of structural safety of particular members (compressive cross-sections) subjected to extreme loadings is presented and illustrated by numerical example.     

钢构件与混凝土墙端板连接的有限元分析

采用通用有限元分析软件对混凝土后锚固受拉节点进行了模拟计算分析,通过比较不同螺栓直径、螺栓间距的条件下锚板的受力性能,探讨了锚板厚度与螺栓间距、直径的关系以及为保证锚板的出平面刚度应采用的厚度。     

加劲冷弯薄壁型钢Z形截面受弯构件有限元分析

为了研究卷边形式对加劲冷弯薄壁型钢Z形截面受弯构件抗弯承载力的影响,在纯弯和非纯弯状态下,对(短、长)直卷边和(短、长)斜卷边加劲冷弯薄壁型钢Z形截面构件进行了有限元分析,分析结果表明:卷边形式是影响构件抗弯承载力的重要因素,构件在非纯弯状态下的抗弯承载力均高于纯弯状态下的抗弯承载力。     

Finite element modelling of structural stainless steel cross-sections

Stainless steel's characteristic nonlinear, rounded stress–strain behaviour requires accurate recognition in numerical modelling. Its response to cold-working is far more pronounced than that of ordinary carbon steel and hence appropriate modelling of the cold-worked corner regions is very important. Despite the importance of geometrical imperfections, their measurement is not a very common practice and assumed models are generally adopted in numerical investigations—often without proper verification. This paper investigates all important aspects for modelling stainless steel cross-sections through carefully designed parametric studies. Different cross-section types have been considered and the numerically obtained load–deformation responses have been compared with selected experimental results; the findings form the basis for specific guidelines. These proposals have been verified by application to all available stainless steel stub column tests obtained from different sources. The predicted numerical results have shown excellent agreement with those obtained experimentally.     

钢筋混凝土结构有限元分析的建模

结合有限元分析时对计算模型的基本要求,介绍了钢筋混凝土结构的三种有限元分析模型,分析了各种模型在钢筋混凝土结构中的应用,总结了各自的特点并进行了具体阐述,以期指导钢筋混凝土结构设计。     

铝合金结构构件可靠度分析

以试验数据为基础,对铝合金结构基本构件(包括轴压构件、受弯构件和偏压构件)进行了设计可靠度分析。分析结果表明,构件类型和荷载组合对于结构构件可靠度的影响很大;在相同荷载条件下,轴压构件的可靠指标最低,受弯构件的可靠指标最高;对于同类构件,参与组合的风荷载越大,其可靠指标越低。最后,针对国产结构用铝合金6061-T6的构件承载力设计提出了合理的抗力分项系数和设计强度建议值。采用本文建议的强度设计值,铝合金结构基本构件的设计可靠指标平均值均大于3.70,完全满足《建筑结构可靠度设计统一标准》(GB 50068—2001)的规定。