共查询到17条相似文献,搜索用时 125 毫秒
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逆K 型管节点广泛应用于海洋平台,其强度是平台结构安全评估的重要课题. 基于ANSYS 软件,应用分区域网格划分法,建立含焊缝的逆K 型管节点有限元模型,分别计算了在轴向载荷、平面内弯矩和平面外弯矩作用下焊缝周围热点应力的分布情况. 通过对105 组逆K 型管节点模型进行分析,获得了其在3 种基本载荷作用下沿焊缝的应力集中系数(stress concentration fctor,SCF),并对主管和支管的SCF 分别进行研究,得出了几何参数对主管和支管的SCF 及极值位置的影响规律. 相似文献
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本文应用ADINA程序对支管轴向受拉和轴向受压的T型管节点模型实例进行了非线性有限元计算.在轴向受压的工况计算中,除考虑材料的物理非线性外,还考虑了几何非线性问题.根据对计算结果的分析,确定了两种工况的极限载荷,以及支管和主管在不同载荷步下的塑性变形区的扩展情况. 相似文献
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对于已含初始裂纹平台管节点的寿命预测很大程度上依靠应力强度因子的精确值,而复杂载荷条件下的节点应力强度因子的计算尚无参数方程直接确定.本文提出了一种含表面裂纹的K节点的有限元网格产生方法,即把整个K节点划分为几个子区域,每个子区域的网格具有不同类型的单元和不同的密度.这种方法在控制网格密度,尤其是控制沿着裂纹边缘单元的边长比方面有其独特的优越性,当所有子区域的网格自动产生后,容易得到整个结构的有限元模型.同时用J积分和位移外推插值法分别计算了一个K型节点沿着裂纹前缘的应力强度因子值,发现:试验得到的应力强度因子值和提出的模型计算结果非常吻合,证明了所提有限元模型的准确性. 相似文献
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对于已含初始裂纹平台管节点的寿命预测很大程度上依靠应力强度因子的精确值,而复杂载荷条件下的节点应力强度因子的计算尚无参数方程直接确定。本文提出了一种含表面裂纹的K节点的有限元网格产生方法,即把整个K节点划分为几个子区域,每个子区域的网格具有不同类型的单元和不同的密度。这种方法在控制网格密度,尤其是控制沿着裂纹边缘单元的边长比方面有其独特的优越性,当所有子区域的网格自动产生后,容易得到整个结构的有限元模型。同时用J积分和位移外推插值法分别计算了一个K型节点沿着裂纹前缘的应力强度因子值,发现:试验得到的应力强度因子值和提出的模型计算结果非常吻合,证明了所提有限元模型的准确性。 相似文献
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《应用力学学报》2020,(3)
对碳纤维复合材料(CFRP)加固含腐蚀TT型管节点进行支管轴向压力静力试验测试。为了研究加固后的效果,又对相同尺寸的未加固TT型管节点进行了试验测试。结果表明:采用CFRP对含腐蚀TT型管节点进行加固可以减小管节点相贯区域处的失效范围,缓解该处的应力集中现象,使主管表面的塑性变形和椭圆化程度得到改善;CFRP加固后管节点的极限承载力提升了22.7%,说明CFRP可有效地提高管节点的极限承载力。基于ABAQUS有限元分析软件,分别对加固前后的TT型管节点进行了仿真模拟,验证了模型(TT-1和TT-1-C)的正确性。参照海洋平台结构中所使用的TT型管节点尺寸参数范围,选取了60个不同尺寸参数的TT型管节点。利用有限元分析法,建立了不同层数的CFRP加固不同尺寸参数(支管与主管的管径比β、主管的径厚比γ)管节点的有限元分析模型。研究结果表明:采用国产碳纤维对海洋平台结构中不同尺寸参数的TT型管节点进行加固,其加固效果十分明显;当TT型管节点尺寸参数一定的情况下,随着CFRP粘贴层数n的增加,管节点的极限承载力随之提升;当CFRP粘贴层数n≥3时,84%的TT型管节点极限承载力的提高率均能达到20%以上;在保持主管外径一定的情况下,当β=0.2~0.61时加固前后管节点的极限承载力与β呈正相关,当γ=12~21时加固前后管节点的极限承载力与γ呈负相关。 相似文献
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任意多孔多裂纹有限大板的应力强度因子分析 总被引:3,自引:0,他引:3
采用各向异性体平面弹性理论中的复势方法,以Faber级数为工具,应用保角映射技术和最小二乘边界配点法,导出内边界条件精确满足,外边界条件近似满足的含多椭圆孔及裂纹群有限大板在任意载荷作用下的应力场、位移场的级数解,建立了任意多椭圆孔及裂纹群有限大板应力强度因子的有效分析方法,讨论了各参数对裂尖应力强度因子及孔边应力集中的影响.数值结果表明,该方法具有计算精度高、收敛速度快、方便快捷等优点,有利于全面系统地研究各参数对结构断裂性能的影响. 相似文献
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Roberta Sburlati 《International Journal of Solids and Structures》2013,50(22-23):3649-3658
The aim of this work is to present an analytical solution to reduce the stress concentration factor (SCF) around a circular hole in an isotropic homogeneous plate subjected to far-field uniaxial loading. In this paper the elastic response of an inhomogeneous annular ring made of functionally graded material (FGM), inserted around a hole of a homogeneous plate, is studied. By assuming that Young’s modulus varies in the radial direction with power law and that Poisson’s ratio is constant, the governing differential equations for plane stress conditions are obtained. Using stress function a general solution in explicit closed form is presented and the SCF investigated to highlight the inhomogeneity effects. Furthermore, the explicit solution for an inner homogeneous ring, with different properties with respect to those of the plate, is explicitly obtained and numerical results are compared between homogeneous ring and FGM ring. 相似文献
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M. E. Fourney 《Experimental Mechanics》1971,11(1):19-25
Problems involving three-dimensional bodies which possess axial symmetry reduce to two-dimensional analytical problems. If a wedge-shaped portion of an axisymmetric body is tested subjected to the proper boundary condition, then a pseudo two-dimensional photoelastic method of testing may be used. This results in tremendous simplification in testing procedures, particularly when slight changes in model geometry are to be made during the course of testing. This method has been applied to axisymmetric solidpropellant rocket grains to conduct a parametric study of various conicyl geometries. Both pressure and thermal loads were considered for a case-bonded grain. Six parameters were required to define the geometry. The effects of these parameters and of the material properties of the grain were investigated, and parametric curves showing the variation of the maximum stress with those parameters are presented. The experimental results are compared with results obtained from a finite-element computer solution. Good agreement is obtained. 相似文献
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Based on the nonlinear Hoek–Brown failure criterion, elastoplastic analytical solutions are developed for the elastoplastic stresses, strains and plastic zones around a circular tunnel subjected to different value of the axial in situ stress. Effects of the transverse in situ stress, the axial in situ stress and the strength parameters of rock masses on the elastoplastic stresses, strains and plastic zones in the surrounding rock masses are investigated. It is found from the numerical results that the stresses, strains, and plastic zones in the surrounding rock depend not only on the transverse in situ stress but also on the axial in situ stress as well as the mechanical parameters of rock masses. 相似文献
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细观力学理论得到的复合材料内应力是均值应力,在进行破坏和强度预报前,必须转化到真实值.对于短纤维复合材料,除了轴向压缩真实应力外,基体其它方向真实应力计算已得到解决,等于其均值应力乘以基体应力集中系数.论文基于弹性力学方法得到了短纤维复合材料轴向压缩下基体的应力场,并据此定义基体的轴向压缩应力集中系数.与基体其它方向应... 相似文献