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圆柱壳撞水时的弹塑性动力屈曲研究 总被引:3,自引:0,他引:3
本文研究圆柱壳在流固中冲击载荷下的弹塑性动力曲问题。建立了液体-气体-固体三相的数学模型。其中结构部分控制方程由弹塑性力学中关于加速度的最小原理获得,本构关系采用增量理论,液体假设为不可压缩,空气层认为最等熵压缩。分别讨论了不同冲击高度时压力变化规律,屈曲对载荷的影响。屈曲沿壳长的分布及发展规律等。 相似文献
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本文研究在轴向冲击作用下,具有初始几何缺陷的圆柱壳的非线性弹性动力屈曲问题。由于冲击过程中作用时间极短,应力波的影响变得相当重要,同时认为圆柱壳经历大挠度变形。分析中不仅考虑圆柱壳的径向惯性力,而且也考虑轴向惯性力和几何非线性的影响。假设圆柱壳中位移和薄膜力可分成轴对称分量和非轴对称分量之和,并引入应力函数表示非轴对称内力,对平衡方程应用伽辽金方法,将导出的和冲击物体的质量对动屈曲性能的影响很大。 相似文献
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对钢质和铜质金属圆柱壳的轴向冲击动力响应进行了实验研究,记录了两种不同材料圆柱壳在大质量低速冲击下的冲击力时程曲线,得到其屈曲模态。采用高速摄像及模拟技术给出了钢质圆柱壳渐进屈曲的全过程,为理解钢质圆柱壳的屈曲机理提供了直观的结果。黄铜质圆柱壳在大质量低速冲击下, 出现整个壳面滿布屈曲波纹的塑性动力屈曲现象,说明高速冲击不是产生塑性动力屈曲的充要条件。像铜这样具有高密度的韧性材料,在大质量低速冲击下,会在轴向产生持续的压缩塑性流作用而出现塑性动力屈曲现象。 相似文献
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水下爆炸载荷作用下环肋加筋圆柱壳结构的弹塑性动力屈曲 总被引:2,自引:0,他引:2
为研究水下爆炸载荷作用下潜艇结构的动力屈曲现象,以潜艇耐压结构的简化模型环肋加筋圆
柱壳结构为研究对象,建立流固耦合有限元分析模型,应用瞬态有限元分析程序MSC.Dytran对该结构在水
下爆炸冲击载荷作用下的弹塑性动力屈曲行为进行研究,基于Budiansky-Roth准则和Southwell方法确定环
肋加筋圆柱壳结构的临界屈曲载荷,讨论结构动力屈曲的影响因素如载荷强度、网格密度、径厚比、长径比、加
筋截面间距、加筋尺寸等对环肋加筋圆柱壳结构动屈曲模态和临界屈曲载荷的影响。结果表明:采用建立的
流固耦合有限元分析模型,应用动力瞬态有限元软件MSC.Dytran可以对加筋圆柱壳结构的动力屈曲行为进
行模拟,模型网格尺寸大小、结构几何参数对结构的动力屈曲临界载荷都有一定的影响,其中加筋圆柱壳结构
的径厚比对结构的动力屈曲临界载荷影响最为显著。 相似文献
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圆柱形薄壳冲击扭转屈曲的实验研究 总被引:1,自引:0,他引:1
本文对受冲击扭矩作用下的圆柱形簿壳扭转屈曲进行了实验研究,利用Hopkinson扭杆使圆柱受阶跃扭矩作用,分析所得到的应变-时间曲线,得到了不同几何参数的圆柱壳的冲击临界扭矩Mder和屈曲波数n及几条定性结论,同时找出了圆柱壳静力扭转屈曲行为和冲击扭转屈曲行为之间的异同。 相似文献
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In this paper, experimental studies are carried out on the buckling of circular cylindrical thin shells under impact torque. Experiments of impact buckling are made on a Hopkinson torsional bar. The torsional bar gives a step torque on the shells. Through an analysis of the strain-time curve obtained in experiment, the dynamic buckling critical torqueM
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and buckling waves numbern of the shell with different geometric data and some qualitative results are obtained. The buckling behavior of circular cylindrical thin shells under static and impact torque is compared. 相似文献
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D. KaragiozovaNorman Jones 《International Journal of Non》2002,37(7):1223-1238
Some characteristic features of the dynamic inelastic buckling behaviour of cylindrical shells subjected to axial impact loads are discussed. It is shown that the material properties and their approximations in the plastic range influence the initial instability pattern and the final buckling shape of a shell having a given geometry. The phenomena of dynamic plastic buckling (when the entire length of a cylindrical shell wrinkles before the development of large radial displacements) and dynamic progressive buckling (when the folds in a cylindrical shell form sequentially) are analysed from the viewpoint of stress wave propagation resulting from an axial impact. It is shown that a high velocity impact causes an instantaneously applied load, with a maximum value at t=0 and whether or not this load causes an inelastic collapse depends on the magnitude of the initial kinetic energy. 相似文献
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轴向应力波作用下圆柱壳弹性轴对称动力失稳有限元特征值分析 总被引:1,自引:0,他引:1
本文运用有限元特征值分析方法对应力波作用下圆柱壳弹性轴对称动力失稳问题进行了研究。基于应力波理论和相邻平衡准则导出了圆柱壳轴对称动力失稳时的有限元特征方程,在此方程中考虑了应力波效应及横向惯性效应,把圆柱壳弹性动力失稳问题归结为特征值问题。通过引入圆柱壳动力失稳时的波前约束条件实现了此类问题的有限元特征值解法。计算结果揭示了圆柱壳弹性轴对称动力屈曲变形发展的机理,以及轴向应力波和屈曲变形的相互作用规律。 相似文献
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Experimental studies on dynamic plastic buckling of circular cylindrical shells under axial impact 总被引:1,自引:0,他引:1
In the present paper, experimental studies on dynamic plasticbuckling of circular cylindrical shells under axial impact are
carried out. Hopkinson bar and drop hammer apparatus are used for dynamic loading. Three groups of circular cylindrical shells
made of copper are tested under axial impact. From the experiments, the first critical velocity corresponding to the axi-symmetric
buckling mode and the second critical velocity corresponding to the non-axisymmetric buckling mode are determined. The present
results come close to those of second critical velocity given by Wang Ren[4–6]. Two different kinds of non-axisymmetric buckling modes oval-shaped and triangle shaped are founded. The buckling modes under
two loading cases, viz. with small mass but high velocity and with large mass and low velocity using Hopkinson bar and drop
hammer, are different. Their critical energies are also discussed.
The project is supported by the National Natural Science Foundation of China (19672039) and the Foundation for Returned Scholar
from Abroad of Shanxi Province 相似文献