发生畸变屈曲的纵向加劲板的受压试验

采用厚4.0mm,名义屈服应力为235.0MPa的中厚钢板制作板件,并分别设置不同刚度的纵向加劲肋,对此纵向加劲板进行受压破坏试验。对发生畸变屈曲或局部与畸变相关屈曲的纵向加劲板的受压极限承载力和性能进行试验和理论研究,结果表明:临界屈曲模式主要取决于纵向加劲肋的刚度和母板的宽厚比。对于某些加劲板,局部屈曲和畸变屈曲之间的相互作用非常明显。畸变屈曲构件和局部与畸变相关屈曲构件展示了较大的后屈曲强度。研究纵向加劲板的的畸变屈曲强度曲线。采用直接强度法提出设计强度简化公式,用于考虑纵向加劲板的畸变屈曲及局部与畸变相关屈曲。将强度曲线与试验和有限元结果对比,验证了曲线的正确性。通过试验研究,得出有关纵向加劲板的屈曲性能的一些结论。     

异形截面轴心受压铝合金构件屈曲性能试验研究

采用试验与数值模拟相结合的方法,研究了异形截面铝合金受压杆件的屈曲破坏模态和屈曲承载力问题,并将试验结果、数值模拟结果以及《铝合金结构设计规范》中相关公式的计算结果进行了对比.结果表明,数值模拟结果与试验结构吻合较好,证明了有限元模型的正确性,并可采用该模型进行异形截面铝合金构件屈曲性能参数分析;规范所研究异形截面铝合金构件没有区分屈曲破坏类型的影响,屈曲承载力的计算结果偏小.     

方形钢管混凝土钢管壁弹性屈曲分析

对方形钢管混凝土钢管壁局部屈曲行为进行弹性分析,推导钢管壁发生局部屈曲时的屈曲系数、屈曲半波长及临界屈曲应力表达式,并与局部屈曲试验研究成果进行比较,提出更为合理的计算公式,为后续的进一步研究打下基础。     

方形钢管混凝土钢管壁弹性屈曲分析

对方形钢管混凝土钢管壁局部屈曲行为进行弹性分析,推导钢管壁发生局部屈曲时的屈曲系数、屈曲半波长及临界屈曲应力表达式,并与局部屈曲试验研究成果进行比较,提出更为合理的计算公式,为后续的进一步研究打下基础.     

冷弯薄壁卷边槽钢轴压构件畸变与局部相关屈曲试验研究

对卷边尺寸不同的两类腹板中间设置加劲卷边槽形截面,共18个冷弯薄壁型钢固支轴压试件进行畸变屈曲与局部屈曲相关作用的静力试验研究。得到试件的屈曲模式、相关屈曲行为、破坏模式以及极限荷载。试验结果表明：畸变屈曲与局部屈曲的耦合相关对试件的变形和极限荷载有不利作用;畸变屈曲与局部屈曲的耦合相关作用存有较大的屈曲后承载力;畸变屈曲与局部屈曲的耦合相关顺序,即畸变屈曲 局部屈曲耦合相关、局部屈曲 畸变屈曲耦合相关,对试件的变形、非线性平衡路径、破坏模式以及极限荷载的影响有所不同。采用ABAQUS有限元软件对试件进行模拟分析,计算结果与试验结果吻合良好。     

卷边槽钢梁柱的畸变屈曲有限元分析

对于卷边槽钢梁柱的畸变屈曲,文献1运用文献4的计算简化模型推导了畸变屈曲弹性计算公式。本文采用文献2的截面,运用有限元分析考虑了单一截面构件在不同参数时构件的弹性和弹塑性屈曲荷载和屈曲模式,并考虑了几何缺陷带来的影响,最后根据试验建立模型并将分析结果与试验结果进行对比。     

方形钢管混凝土局部屈曲有限元分析

应用通用有限元程序,对方形空钢管、方形钢管混凝土两种不同构件进行了特征值屈曲分析,研究了该两种不同构件的屈曲模式及临界屈曲应力,并与试验研究成果及理论分析结果进行了比较,结果吻合良好.     

蒙皮板整体剪切屈曲性能试验及有限元分析

在蒙皮体的各种破坏形式中,整体剪切屈曲破坏是具有控制作用的破坏形式之一。对目前国内常用的YX20-166-830型压型钢板组成的6个不同边界连接的蒙皮板进行了抗剪试验研究,探讨边界连接形式对整体屈曲荷载的影响。在试验的基础上进行了有限元分析,将试验结果、有限元计算结果和理论结果进行了比较。屈曲荷载的试验值与有限元计算值相差较小,可见有限元计算模型可以作为进行蒙皮体抗剪性能分析的辅助手段。另外,通过屈曲荷载的试验值和简化公式值比较,得到了边界连接形式对整体屈曲荷载的影响,进一步完善了蒙皮板整体剪切屈曲的计算公式。     

轴压圆柱薄壳的屈曲分析

通过对大量的试验数据进行数理统计分析,提出了计算轴心受压圆柱壳屈曲应力的经验公式,该式表明在其他因素相同的情况下,屈曲应力与壳体厚度t1.5成正比,而经典理论则认为屈曲应力与厚度t成正比.通过圆柱壳在自重作用下的屈曲试验和有限元分析,验证了该经验公式的正确性.非线性有限元全过程分析显示,圆柱壳在其荷载位移全过程曲线上存在一个近似水平的后屈曲承载力"平台"(Plateau),与之相应的是在壳壁上形成了一个局部"凹陷"(Dimple),而试验得到的平均屈曲应力约等于平台对应的后屈曲应力.由此发现,试验或经验公式所得到的实际上是圆柱壳的后屈曲应力,而并非其初始屈曲应力.承受局部轴向压力的圆柱壳,在压力作用点附近亦形成一个与后屈曲承载力平台对应的局部凹陷.同上述凹陷一样,这类凹陷需要一个近似常量的压力来维持其不稳定的后屈曲平衡.给出了该作用力的计算公式,且它与t2.5成正比,从而亦间接证明了后屈曲应力或经验公式确定的应力与t1.5成正比的关系.对以往试验现象作出了合理解释,提出的两个计算屈曲应力和局部屈曲荷载的公式具有理论意义和实用价值.     

铝制蜂窝夹芯板的强度特性

铝夹芯结构非常适合于设计飞机、高速列车和快艇等轻型交通系统。研究目的主要是明确包含铝蜂窝状内芯的铝制夹芯板在理论和试验中的强度特性。对弯曲、轴压和侧向撞击荷载作用下的铝蜂窝夹芯板构件进行了一系列强度试验。在相应荷载作用下,运用简化理论分析蜂窝夹芯板的弯曲变形、屈曲/极限强度和破坏强度。同时也讨论了结构失效模式,并给出了试验数据。     

An investigation of lightly profiled sandwich panels subject to local buckling and flexural wrinkling effects

Sandwich panels exhibit various types of failure modes depending on the steel face used. For the flat and lightly profiled sandwich panels, flexural wrinkling is an extremely important design criterion as the behaviour of these panels is governed mainly by flexural wrinkling. However, in the lightly profiled panels, when the depth or spacing of the ribs increases, flat plate buckling between the ribs occurs leading to the failure of the entire panel due to the interaction between local buckling and flexural wrinkling modes. Current design formulae for sandwich panels do not consider such interactive buckling effects. To obtain a safe design solution, this interactive buckling behaviour should be taken into account in the design of lightly profiled sandwich panels. Therefore a research project was undertaken to investigate the interactive buckling behaviour of lightly profiled panels with varying depths and spacings of the ribs using a series of experiments and finite element analyses. A new improved design formula was developed for the safe and economical design of lightly profiled panels that takes into account the interaction between local buckling and flexural wrinkling. This paper presents the details of this investigation, the results and the new design formula.     

焊接工形梁在纯弯作用下的腹板高厚比限值及极限承载力

通过对腹板在弹性、弹塑性阶段受力特征的研究 ,推导出腹板不设置加劲肋时的高厚比限值 ;采用非线性有限元分析了腹板屈曲后梁的极限承载力 ,并给出了便于设计应用的简化强度验算公式 ;分析中考虑了初始弯曲和残余应力的影响。推荐公式可供《钢结构设计规范》(GBJ1 7- 88)作补充参考。     

夹层板轴向受压时屈曲后性能的有限元分析

以Narayan Pokharel,Mahen Mahendran试验[1]模型为研究依据,用有限元法对受单向轴向压力作用的夹层板进行了屈曲以及屈曲后性能分析。根据Winter公式计算出了板件的有效宽度,并与有限元计算结果以及试验结果进行比较,发现当夹层板宽厚比较大时,Winter公式过高地估计了板件的有效宽度,结果是偏于不安全的。最后,提出了有效宽度的建议公式。     

钢-聚氨酯夹层板稳定分析

分别建立了钢-聚氨酯夹层板和普通钢板的有限元模型,在边界条件、加载情况均相同的条件下进行有限元稳定分析,夹层板采用板-实体-板结构模拟,结果表明在相同条件下,夹层板比普通钢板的屈曲强度均有较大程度的提高。同时进行了保持一定条件不变,分别改变夹芯层厚度、面层钢板厚度模拟分析,结果表明在一定范围内,夹芯层厚度与钢面板厚度增大,夹层板的屈曲临界荷载值也随之增大。夹芯层的抗弯刚度和横向剪切变形对板的影响不可忽略。     

大宽厚比梯形腹板H形短柱的极限承载力

通过对具有轴对称梯形腹板的H形短柱极限承载力的试验 ,并进行相应的有限元计算与分析表明 ,在静力荷载条件下 ,工程构件常用范围内的楔率对具有相同底面尺寸的H形短柱的极限承载力影响不大 ;变截面构件的轴压极限承载力可以由小端截面的屈服承载力和有效截面承载力之间的较小者确定。     

Finite element analysis and design of sandwich panels subject to local buckling effects

Past research into the local buckling behaviour of fully profiled sandwich panels has been based on polyurethane foams and thicker lower grade steels. The Australian sandwich panels use polystyrene foam and thinner and high strength steels, which are bonded together using separate adhesives. Therefore a research project on Australian sandwich panels was undertaken using experimental and finite element analyses. The experimental study on 50 foam-supported steel plate elements and associated finite element analyses produced a large database for sandwich panels subject to local buckling effects, but revealed the inadequacy of conventional effective width formulae for panels with slender plates. It confirmed that these design rules could not be extended to slender plates in their present form. In this research, experimental and numerical results were used to improve the design rules. This paper presents the details of experimental and finite element analyses, their results and the improved design rules.     

Elastic interactive buckling strength of corrugated steel shear wall under pure shear force

Different ways have been presented to prevent elastic buckling of steel shear walls. One of these solutions is corrugated shear wall. In this type of wall, shear buckling strength increases without increasing the thickness of the panel. Numerical modeling results indicate that, always, shear buckling strength of corrugated panels is more than the flat panels and with the right choice of the geometric parameters of corrugated panels; without increasing the thickness of the panel, we can improve buckling strength significantly. In the trapezoidal corrugated panels, reducing the width of the subpanels do not always increase buckling strength of the panel, but it changes the panel buckling shape from the local buckling mode to the global buckling. In addition, in panels, with the low width of the subpanels, elastic buckling does not happen in the subpanels. Comparing numerical analysis with the theoretical relations showed that the results of numerical analysis with the relations that include local buckling, global buckling, and shear yielding stress, have a better approximation and in another word, interaction buckling is the combination of the local buckling, global buckling, and shear yielding stress.     

Untersuchungen zur Drehbettung von biegedrillknickgefährdeten Trägern durch Sandwichelemente

Investigation of the torsional restraint of sandwich panels against lateral torsional buckling of beams. Experimental investigations and parametric FE‐analyses show that the torsional restraint of sandwich panels against lateral torsional buckling of beams can be expressed by a tri‐linear moment‐rotation‐relationship. Formulae are given for different profile types combined with sandwich panels for roof and wall for calculation of the parameters of this relationship. From this moment‐rotation‐relationship, which depends on the lateral load of the beam, the rotational stiffness c_{ϑ A} of the connection is obtained as secant stiffness. The rotational stiffness c_ϑ required for the design against lateral torsional buckling according to DIN 18800 part 2 is governed by c_{ϑ A}. The rotational stiffness values c_{ϑ A} of the connection, which so far were only known for two types of elements, can be calculated with this method for all common types of sandwich panels and different types of constructions.     

Improved prediction of simultaneous local and overall buckling of stiffened panels

In this paper, improved expressions for elastic local plate buckling and overall panel buckling of uniaxially compressed T-stiffened panels are developed and validated with 55 ABAQUS eigenvalue buckling analyses of a wide range of typical panel geometries. These two expressions are equated to derive a new expression for the rigidity ratio (EI_x/Db)_CO that uniquely identifies “crossover” panels—those for which local and overall buckling stresses are the same. The new expression for (EI_x/Db)_CO is also validated using the 55 FE models. Earlier work by Chen (Ultimate strength analysis of stiffened panels using a beam-column method. PhD Dissertation, Department of Aerospace and Ocean Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, 2003) had produced a new step-by-step beam-column method for predicting stiffener-induced compressive collapse of stiffened panels. An alternative approach is to use orthotropic plate theory. As part of the validation of the new beam-column method, ABAQUS elasto-plastic Riks ultimate strength analyses were made for 107 stiffened panels—the 55 crossover panels and 52 others. The beam-column and orthotropic approaches were also used. A surprising result was that the orthotropic approach has a large error for crossover panels whereas the beam-column method does not. Some possible reasons for this are suggested.     

考虑桩-土非线性共同作用的横向受荷桩分析模型

基于桩周土 (砂土及粘土 )的常规三轴压缩试验 ,提出了一种有效计算水平横向受荷桩荷载与变形非线性关系的应力 -应变锥楔模型 (SSCW)法。该法从桩 -土系统共同作用机理出发 ,充分考虑了桩 -土间相互作用属性的变化对p -y曲线分析结果的影响。计算表明 ,通过SSCW法得到的桩土反应数值与实测值有良好的一致性