Three-Dimensional Thermo-Elastic-Plastic Finite Element Method Modeling for Predicting Weld-Induced Residual Stresses and Distortions in Steel Stiffened-Plate Structures

The objective of the present paper is to develop nonlinear finite element method models for predicting the weld-induced initial deflection and residual stress of plating in steel stiffened-plate structures. For this purpose, three-dimensional thermo-elastic-plastic finite element method computations are performed with varying plate thickness and weld bead length (leg length) in welded plate panels, the latter being associated with weld heat input. The finite element models are verified by a comparison with experimental database which was obtained by the authors in separate studies with full scale measurements. It is concluded that the nonlinear finite element method models developed in the present paper are very accurate in terms of predicting the weld-induced initial imperfections of steel stiffened plate structures. Details of the numerical computations together with test database are documented.

Lateral load-carrying capacity analyses of composite shear walls with double steel plates and filled concrete with binding bars

A method is developed to predict the lateral load-carrying capacity of composite shear walls with double steel plates and filled concrete with binding bars(SCBs). Nonlinear finite element models of SCBs were established by using the finite element tool, Abaqus. Tie constraints were used to connect the binding bars and the steel plates. Surface-to-surface contact provided by the Abaqus was used to simulate the interaction between the steel plate and the core concrete. The established models could predict the lateral load-carrying capacity of SCBs with a reasonable degree of accuracy. A calculation method was developed by superposition principle to predict the lateral load-carrying capacity of SCBs for the engineering application. The concrete confined by steel plates and binding bars is under multi-axial compression; therefore, its shear strength was calculated by using the Guo-Wang concrete failure criterion. The shear strength of the steel plates of SCBs was calculated by using the von Mises yielding criterion without considering buckling. Results of the developed method are in good agreement with the testing and finite element results.

Nonlinear static response of piezoelectric plates considering electro-mechanical coupling

Nonlinear static analysis of piezoelectric plates has been carried out using nonlinear finite element method considering electro-mechanical coupling,The geometrical nonlinearity has been taken into account and electric potential is assumed to be quadratic across the plate thickness,The governing equations are obtained using potential energy and Hamilton's principle that includes elastic and piezoelectric effects.The finite element model is derived based on constitutive equation of piezoelectric material accounting for coupling between elasticity and electric effect using higher order plate elements,Results are presented for piezoelectric plate under different mechanical boundary conditions,Numerical results for the plate are given in dimensionless graphical forms.Effects of boundary conditions on linear and nonlinear response of the plate are also studied.The numerical results obtained by the present model are in good agreement with the available solutions reported in the literature.

A Kind of Super-parametric Finite Element for Geometric Nonlinear Analysis of Plates and Shells

A new kind of super parametric finite elements for geometric nonlinear analysis of plates and shells is presented.Besides the nodes on the middle surface, additional virtual nodes are used to determine the normal to the middle surface.There are three displacement d.o.f.for each node of the element, and two transverse shear strains are taken as additional independent d.o.f.for each node on the middle surface.Therefore, the element is suitable for large rotation analysis of plates and shells. It can also be easily applied to the analysis of laminated and sandwich shells and plates.Numerical examples are given to show the accuracy and efficiency of the element.

Progressive Collapse of Steel Frames

This paper investigates the behavior of steel frames under progressive collapse using the finite element method. Non-linear finite element models have been developed and verified against existing data reported in the literature as well as against tests conducted by the authors. The nonlinear material properties of steel and nonlinear geometry were considered in the finite element models. The validated models were used to perform extensive parametric studies investigating different parameters affecting the behavior of steel frames under progressive collapse. The investigated parameters are comprised of different geometries, different number of stories and different dynamic conditions. The force redistribution and failure modes were evaluated from the finite element analyses, with detailed discussions presented.

Study of a new-type of steel buckling-restrained brace

The rectangle core plate of all-steel buckling-restrained braces(BRBs) usually exhibit obvious local buckling, due to the lack of longitudinal restraint from the encasing tube. To eliminate the undesirable effects, a novel steel BRB is proposed. In this new-type steel BRB, two T-shaped steels are adopted as the minor restraint elements to restrain the core plate instead of infilled concrete or mortar. Meanwhile, the ingot-iron material with low yielding strength and high elongation is applied to the steel core to study the mechanical properties of steel BRBs. To validate the theoretical requirements for the width-to-thickness ratio of the steel core and the thickness of angle steel, quasi-static tests of eight specimens were conducted. The tests focused on the energy dissipation capacity and failure modes of the proposed steel BRBs. Nonlinear finite element analysis was also carried out to validate the experimental results. Both the aforementioned results imply that appropriately designed steel BRBs can meet the performance requirements for BRB components.

新型空心管状翼缘钢板组合梁设计理念与力学性能

工字钢组合梁桥正朝着少主梁、精简横向联系的方向发展。与传统多主梁复杂横向联系组合梁桥相比,双主梁桥由于采用了开口截面的结构形式,极大地削弱了其抗扭能力,在偏载作用下会产生较大的变形及翘曲应力,使钢主梁处于弯扭耦合的受力状态。空心管状翼缘钢板组合梁采用空心钢管取代传统的平板上翼缘,提升了稳定性,改善了结构性能。本文通过理论分析和实体有限元法的计算,研究了单梁在自重与横向风荷载作用下的稳定性;对非组合截面的组合体系下的稳定性能进行了分析与比较,并分离出扭转翘曲应力和纵向正应力,研究了不同跨径下扭转效应的影响。最后,对横向联系、加劲肋的影响进行了分析。研究结果表明,空心管状翼缘钢板组合梁桥扭转刚度大于传统工字形截面组合梁扭转刚度,自身横向稳定性好,并且需要较少的横向联系与加劲肋,可实现单梁吊装,避免采用过多临时加固及支撑措施,提高施工效率。

焊接多腔双钢板-混凝土组合剪力墙抗震性能分析

大多数双钢板-混凝土组合剪力墙采用螺栓连接或焊接肋的方式使钢板和混凝土协同工作。然而,这种连接方式可能导致整体性和塑性变形效率较低,且制作复杂,焊接多腔双钢板-混凝土组合剪力墙能够有效地避免这些问题。为了深入研究焊接多腔双钢板-混凝土组合剪力墙的抗震性能,基于约束混凝土真三轴塑性-损伤本构模型和钢材弹塑性混合强化-韧性损伤本构模型,建立了组合剪力墙的精细化三维实体-壳模型,将模拟所得的滞回曲线、骨架曲线、刚度退化曲线、弹性刚度、承载力、累积耗能、等效阻尼粘滞系数和延性系数与已有拟静力试验结果相比较,发现两者吻合较好。分析结果表明:轴压比对组合剪力墙模型算例刚度和承载力的影响较小,而随剪跨比增大,组合剪力墙模型算例的刚度和承载力呈线性降低;轴压比对组合剪力墙模型算例总塑性耗能的影响较小,而剪跨比的影响较大,剪力墙总塑性耗能随剪跨比增大而降低;轴压比和剪跨比都不会改变算例各部件的耗能分配机制,即组合剪力墙模型算例以外钢板和内隔板耗能为主。

带钢筋桁架楼承板的PRC连梁抗震性能试验研究及数值分析

为适应超高层建筑以及现代工业化住宅建筑体系迅速发展的需要,提出了一种带钢筋桁架楼承板的新型钢板-混凝土组合(plate-reinforced composite,PRC)连梁。通过拟静力试验,分析了不考虑楼板作用、带普通钢筋混凝土(reinforced concrete,RC)楼板及带钢筋桁架楼承板PRC连梁的破坏形态、承载能力、变形能力和耗能能力等。在此基础上,采用ABAQUS软件分析在不同峰值荷载作用下钢筋桁架楼承板PRC连梁的混凝土、钢板和钢筋骨架的应力发展情况。研究结果表明:钢筋桁架楼承板的设置能显著提高小跨高比PRC连梁的受剪承载力、耗能能力和延性,设置楼板能显著提高连梁的峰值荷载,且带钢筋桁架楼承板对PRC连梁承载力的提升比带普通RC楼板更强,其连梁试件PRC-S3的正向峰值荷载比不带楼板连梁PRC-NS1和带普通RC楼板连梁PRC-S2分别提升了31%和18%,但带楼板连梁在梁板交界处产生通缝之后连梁的刚度退化较为严重;带钢筋桁架楼承板的PRC连梁具有优越的耗能能力,在连梁跨度范围内均出现了显著的对角压杆,主压杆及其衍生压杆共同构成桁架作用来承受剪力;楼承板桁架上下弦钢筋以及连梁纵筋均在连梁根部位置出现应力集中,且连梁试件PRC-S3破坏点对应的累积耗能是不带楼板试件PRC-NS1的1.39倍。

正交异性钢-钢纤维混凝土组合桥面板疲劳极限状态研究

为了解正交异性钢-钢纤维混凝土(Steel Fiber Reinforced Concrete,SFRC)组合桥面板的疲劳性能及失效机理,以川南城际铁路临港长江大桥为背景,设计、制作正交异性钢-SFRC组合桥面板足尺模型进行疲劳试验,采用ANSYS软件建立试件有限元模型,研究关键细节的疲劳应力和开裂等情况。基于有限元模型,分析不同设计参数(钢顶板厚度、栓钉布置、SFRC抗拉强度及层厚)下组合桥面板疲劳极限状态的失效模式,并提出了主要控制参数取值建议。结果表明:200万次疲劳加载后足尺模型的实测最大裂缝宽度为0.136 mm,出现在SFRC层上缘,钢结构未开裂,组合桥面板疲劳性能良好;组合桥面板疲劳极限状态主要由SFRC层开裂控制,钢顶板厚度、栓钉布置对组合桥面板疲劳性能的影响较小,SFRC抗拉强度和层厚对组合桥面板疲劳性能影响较大,为主要控制参数;在常规正交异性钢桥面板上铺设薄层(厚度不超过50 mm)SFRC时,SFRC抗拉强度不应小于5 MPa,在常规正交异性钢桥面板上铺设普通SFRC(钢纤维体积含量不高于1%,抗拉强度不高于3 MPa)时,SFRC层厚不宜低于100 mm。

基于ABAQUS的减速器摩擦钢片热力学分析

为解决减速器摩擦钢片制动过程中由于热传导不均发生开裂或变形的问题,基于有限元分析软件ABAQUS创建有限元分析模型,对常规制动工况下的减速器摩擦钢片进行热力学分析。计算结果表明:制动前期摩擦钢片接触压力均匀分布;制动中后期由于摩擦热量传导不均,接触压力分布沿径向呈中径较高、内外径略低状态,周向压力分布均匀,最大压应力在许用压应力范围内。在此基础上,进一步计算摩擦钢片温度场及热应力分布,从计算云图看出,摩擦面径向温度梯度和热应力梯度没有明显变化,温度场及热应力分布均匀,且最大热应力远低于许用热应力。综合分析常规制动工况下的接触压力、温度场及热应力分布状态,结果显示:摩擦钢片不会产生径向裂纹或碟形翘曲变形,满足减速器制动需求。通过摩擦钢片热力学分析,可为电动叉车制动装置的设计与制造工艺改进提供坚实的数据基础。

不锈钢端板攻丝高强度螺栓连接抗拉承载力分析

下文对新型不锈钢端板攻丝连接与传统高强度螺栓连接抗拉受力性能进行试验对比,并对不锈钢端板攻丝连接进行有限元分析,研究其破坏形态、受力机理和极限承载能力。分析结果表明:随着攻丝端板板厚的增加,连接件破坏形态由攻丝端板破坏转向螺栓第一排螺纹处拉断破坏,揭示了新型不锈钢端板攻丝连接形式的破坏机理,且攻丝连接件极限承载力达到了传统连接理论值,表明连接件的可靠。

双钢板混凝土组合墙偏心受压性能试验研究

为了研究双钢板混凝土组合墙在偏心受压荷载下的结构性能,设计制作了5个试件,以偏心距离和墙板厚度作为研究参数,进行偏心受压试验.利用ABAQUS软件对试件进行有限元分析,并采用截面分析法计算试件在轴力与弯矩共同作用下的截面承载力.试验结果表明,试件最终出现钢板局部屈曲与混凝土受压破坏.根据试验荷载-位移曲线,计算得到试件延性系数为1.28~1.92.墙厚相同时,随着加载偏心距离的增加,承载力逐渐下降.偏心距离相同时,增加墙体厚度可以有效提高试件承载能力.偏心受压试件的截面应变分布满足平截面假定.承载力试验值与有限元模型计算值和理论计算值的最大误差分别为4%和9%.

轴压比对波纹侧板-方钢管混凝土柱抗震性能的影响研究

为研究轴压比对波纹侧板-方钢管混凝土柱抗震性能的影响,使用ABAQUS软件建立了组合结构柱的有限元模型,通过破坏形态和滞回曲线等对模型的准确性进行了验证,运用参数模型讨论了不同轴压比对试件的破坏形态、滞回曲线、骨架曲线、压弯承载力和延性系数的影响。结果表明,随着轴压比增大,方钢管的高应力高度逐渐升高,波纹板的应力由水平分布变化为斜向分布;提高轴压比会使试件的压弯承载力和延性系数呈先升高后降低的趋势,建议轴压比不应超过0.30,满足规范中对延性系数的要求并在一定程度上提高结构的压弯承载力。通过合理控制轴压比,可以提升波纹侧板-方钢管混凝土柱抗震性,确保其在实际应用中的安全性和稳定性。

钢箱梁横隔板优化布置对顶推施工力学性能的影响分析

针对斜交连续钢箱梁的横隔板布置方式,提出在钢箱梁斜交支撑位置处加密设置正交横隔板,通过建立钢箱梁的有限元全桥模型,对不同横隔板布置方案进行了对比分析。在顶推最不利工况下,分析了不同横隔板布置方案下的结构内力、挠度、支座反力、局部应力及扭转变形,验证了新型横隔板布置方案的可行性。结果表明,新型横隔板布置方案与常规布置方案在支座反力及弯矩分布上基本一致,优势主要体现在易于加工制造、整体自重较小且能显著减小支撑区域应力水平。新型斜交连续钢箱梁横隔板优化布置方式在顶推施工中满足强度设计要求。

内置薄钢板的纤维复合材料接头连接性能

为研究内置薄钢板的纤维复合材料接头的连接性能,对该连接接头结构展开单轴拉伸试验.采用ABAQUS重点对影响连接性能的端径比(E/D)、边径比(S_(W)/D)、列径比(S/D)和孔径厚度比(D/t)等几何连接参数进行研究.研究结果表明:内置薄钢板的纤维复合材料连接接头相较于无内置钢板的纤维复合材料连接接头,具有更大的刚度,峰值荷载和峰值位移分别提升约50%和58%,孔周应力集中现象有所降低,改善了破坏模式,表现出较好的承载能力与延性性能;几何连接参数对连接接头的承载能力和失效模式有较大的影响,为提高连接效率,建议选用参数S_(W)/D≥2、E/D≥4、4≤S/D≤5、1.6≤D/t≤2.

大跨越钢管塔复杂管板-相贯节点承载力计算方法

以白鹤滩—浙江±800 kV特高压直流输电线路安徽池州段长江大跨越钢管输电塔为工程背景,对输电塔塔头下横担与主管连接的复杂管板-相贯节点的受力性能进行了研究。建立了节点有限元模型并对模型的合理性进行了对比验证,进一步地,对节点关键性几何尺寸进行参数化分析,研究其对节点承载力的影响。结果表明,节点水平支管和斜管承载力的最主要影响因素分别为水平支管几何尺寸和斜支管连接节点板厚度。在此基础上,采用节点逐层拆分方法进行了承载力推导并给出了节点承载力建议计算公式,公式结果与节点实际承载力的误差在12%以内,可为该节点的实际工程应用提供参考。

新型高强钢板在结构抗接触爆炸中的应用

为研究NFB700E1高强钢板对钢筋混凝土结构抗震塌性能的提升效果,开展了五组组合结构抗接触爆炸试验(以Q345普通钢板为对照组),并基于试验结果,建立了较为真实的数值仿真模型,通过多组数值仿真算例,计算出钢筋混凝土-防震塌钢板组合结构的相当不震塌系数,量化了防震塌钢板对钢筋混凝土抗震塌能力的提升幅度。结果表明:抗爆试验中,随着钢筋混凝土靶板厚度减少,其爆坑等效直径、爆坑深度和防震塌钢板的最大变形量均呈增大趋势;通过对比爆坑深度和钢板最大变形量等参数,不断迭代优化,得到了吻合程度较高的有限元数值仿真模型;计算得到钢筋混凝土-防震塌钢板组合结构和钢筋混凝土的相当不震塌系数,其中NFB700E1高强钢板8 mm厚时相当不震塌系数约为0.141,6 mm厚时约为0.159,相较于钢筋混凝土(0.475),相当不震塌系数分别提高了70.3%和66.5%;相较于Q345普通钢板(0.230),相当不震塌系数分别提高了38.7%和30.9%。本工作建立的数值仿真模型可拓展延伸到更多工况,为其他防护工程抗震塌研究提供借鉴。

新型高延性混凝土-压型钢板组合楼板抗弯承载力有限元分析

组合楼板是装配式建筑中的重要构件,楼板的选型和设计对结构的安全性和适用性有着重要意义。新型高延性混凝土-压型钢板组合楼板能在施工现场直接组装使用,其次在使用较少混凝土材料的情况下,采用高延性混凝土材料控制裂缝宽度,混凝土与压型钢板组合,形成蒙皮效应,提高楼板整体受力性能。同时加入保温隔热材料,提高楼板的实用性。为进一步了解钢板、混凝土、封边形式的相互作用机理,本工作采用ABAQUS建模,利用已有的实验数据对模型的可靠性进行验证;在此基础上,对压型钢板厚度、混凝土类别、封边形式开展详细分析。研究表明:相较于普通混凝土,使用高延性混凝土组合楼板时,楼板刚度和平面内承载能力显著提高;增大压型钢板厚度,试件的刚度、屈服荷载和极限承载力增加,但变化不明显。采用板侧厚封形式可以显著提升楼板刚度及平面内承载能力,板侧厚封的楼板性能明显优于薄封和不封的楼板。研究结果为新型高延性混凝土-压型钢板组合楼板的设计与工程应用提供参考。

小口径CFRP-方截面钢管混凝土受弯性能研究

为研究小口径CFRP-方截面钢管混凝土的受弯性能,使用钢管外径分别为30、32、35 mm的3种试件(分别命名试件A、B和C)开展12组三点弯曲试验,观察试件的破坏形态并获得荷载-位移曲线。通过测得试件应变变化,对试验构件受弯性能进行分析。利用有限元软件ABAQUS对试件进行非线性有限元分析,并对钢管与水泥之间的黏结能力、水泥立方体试块抗压强度以及CFRP布厚度3组参数进行参数敏感性分析。研究结果表明:钢管内填充水泥与外缠CFRP布均可以提高试件的抗弯承载力最大值以及抗弯刚度;当钢管、水泥、CFRP布3种材料结合在一起时,提升效果最为明显,A、B、C这3种试件的抗弯承载力最大值分别提高了81.6%、93.3%和92.6%;钢管内是否填充水泥与试件的最终破坏形态有明显关联。有限元分析与试验所得荷载-位移曲线吻合较好,破坏模式一致。CFRP布厚度对抗弯承载力最大值以及梁的抗弯刚度有明显影响。