A NEW HIGH-ORDER MULTI-JOINT FINITE ELEMENTFOR THIN-WALLED BAR

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用有限元法分析了开口薄壁圆弧曲梁的非线性弹性屈曲，并通过对有限元计 算结果的非线性回归分析，给出了开口薄壁曲梁极限承载力的实用估算公式.     

Nonlinear vibrations of cylindrical shells with initial imperfections in a supersonic flow

The paper studies the dynamics of nonlinear elastic cylindrical shells using the theory of shallow shells. The aerodynamic pressure on the shell in a supersonic flow is found using piston theory. The effect of the flow and initial deflections on the vibrations of the shell is analyzed in the flutter range. The normal modes of both perfect shells in a flow and shells with initial imperfections are studied. In the latter case, the trajectories of normal modes in the configuration space are nearly rectilinear, only one mode determined by the initial imperfections being stable __________ Translated from Prikladnaya Mekhanika, Vol. 43, No. 9, pp. 63–73, September 2007.     

多孔材料填充薄壁结构吸能的相互作用效应

研究多孔材料填充薄壁结构的相互作用效应产生的机理,并建立了表征模型. 以泡沫 铝填充帽形结构为例,发现压溃的填充物分为致密区、过致密区和未变形区3个区域. 基于 理想可压缩假设建立了填充多孔材料分析模型,获得各区域体积变化和等效应变等关系;结 合薄壁结构超叠缩单元模型,对填充结构各组分的能量吸收进行了拆分. 研究表明,薄壁结 构的吸能略有增加,多孔材料的吸能增加40{\%}左右. 过致密区的形成是相互作用效应的 主要原因.     

薄壁结构局部-整体相关屈曲研究现状

薄壁结构因屈曲而丧失承载能力的现象日益突出,局部屈曲与总体屈曲的相互作用成为必须考虑的问题。本文综述了薄壁结构局部-整体相关屈曲研究若干重要方面的理论发展和现状,并试图对进一步研究提出建议。      

ENERGY ABSORPTION CONTROL CHARACTERISTICS OF AL THIN-WALLED TUBES UNDER IMPACT LOAD

An experimental investigation was carried out to study the energy absorption characteristics of thin-walled square tubes subjected to dynamic crushing by impact loading to develop the optimum structural members. Here, the controller is introduced to improve and control the absorbed energy of thin-walled square tubes in this paper. When the controller were used, the experimental results of crushing of square tubes controlled by the controller＇s elements showed a good candidate for a controllable energy absorption capability in impact crushing.     

基于双剪应力屈服准则的受内压管道爆破压力分析

采用双剪应力屈服准则,对在内压作用下的无缺陷管道进行了塑性极限分析,得到了管道爆破压力的计算公式;并且将结果与基于Tresca、Mises、平均剪应力屈服准则得到的爆破压力进行了比较.研究结果表明:爆破压力随着管道材料的应变硬化指数的增大而减小,随着管道厚径比的增大而增大;此外,基于双剪应力屈服准则得到的管道爆破压力为爆破压力的上限,而基于Tresca屈服准则得到的爆破压力为管道爆破压力的下限.     

薄壁钢管再生混凝土轴压实验研究

通过对9个薄壁圆钢管再生混凝土短柱和9个薄壁方钢管再生混凝土短柱进行的轴压试验研究,比较了三种方法测定试件轴向变形的差异,分析了不同取代率和不同截面形式薄壁钢管再生混凝土的破坏变形特征,并运用不同设计规程对薄壁钢管再生混凝土的承载力强度进行了计算分析。得出薄壁钢管再生混凝土的变形破坏形式与普通薄壁钢管混凝土相似,及再生混凝土取代率对试件极限承载力和变形能力有一定影响的结论。另外根据计算比较,得到各规程在计算薄壁钢管再生混凝土极限承载力时的适用性。     

Calculation of the long-term strength of thin-walled polymeric tubes under biaxial loading

The problem on calculating the failure time of thin-walled polymer tubes in creep under internal pressure, internal pressure with tension, pure torsion, and torsion with tension is solved. The solution is constructed based on the concept of equivalent stresses. A mixed long-term failure criterion taking into account the sings of principal stresses is used as the equivalent stress. The calculation results are in a satisfactory agreement with experimental data.Translated from Mekhanika Kompozitnykh Materialov, Vol. 40, No. 6, pp. 811–826, November–December, 2004.     

大型空间结构的热-结构动力学分析

空间结构在辐射换热条件下的热诱发振动是导致空间结构失效的一种典型模式。弄清热诱发振动的机理是理解热诱发振动失效的基础。本文针对常见的空间薄壁杆件结构，提出了一种能够对复杂结构及加热条件进行比较准确的温度场和热诱发振动分析的有限元方法。首先利用一种Founer-有限元方法，同时考虑杆截面内平均温度和温差，求解了包含辐射非线性的瞬态热传导问题，并推荐了一种有效降低求解规模的减缩近似方法-Lanczos方法。在此基础上，用有限元法求解了杆件结构的热诱发振动问题，并就杆截面内平均温度和温差对结构振动的影响以及最大动静态响应的比值分别进行了讨论．合理地解释了一类常见的热诱发振动现象，本文的数值算例说明了这点。