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复合材料中矩形夹杂角端部力学行为分析 总被引:1,自引:1,他引:0
提出了一种分析矩形夹杂角端部奇异应力场的新型杂交有限元方法,该方法在分析矩形夹杂角端部奇异应力场时,需要在夹杂端部构造一个超级单元。超级单元的刚度矩阵可以通过夹杂端部特征问题数值解建立。我们用这种方法计算了单向载荷作用下无限大均质板中单个矩形夹杂角端部奇异应力场,并与现有的数值解进行了比较。比较结果表明:本文提出的方法是可行的、有效的,而且数值结果精度高。为说明本文方法适用范围更广,文章最后讨论了各向异性弹性材料和横观各向同性压电材料中矩形夹杂角端部电弹性场行为。 相似文献
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本文首先利用作者曾提出的一维有限元特征分析方法计算所得到的尖锐夹杂角端部应力奇异指数和奇异应力场、位移场角分布函数,并依据Hellinger-Reissner原理,开发出了一个特殊的、能够反映夹杂角端部局部弹性现象的n结点多边形超级角端部单元,然后将该超级单元与标准的4结点杂交应力单元耦合在一起构建了一种分析异形夹杂角端部奇异弹性场的新型特殊杂交应力有限元方法.文中给出了两个应用算例,算例结果表明:本文方法不仅使用单元少、计算结果精度高,而且适用范围广,可拓展应用于分析复合材料微结构组织与力学行为关系. 相似文献
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采用一种新型的杂交元模型和一种单胞模型来解决周期分布多边形夹杂角部的奇异性应力相互干涉的问题。新型杂交元模型是基于广义Hellinger-Reissner变分原理建立的,其中奇异性应力场分量和位移场分量是采用有限元特征分析法的数值特征解得到的。使用当前的新型杂交元模型,只需要在夹杂角部邻域的周界上划分一维单元,避免了像传统有限元模型那样需要划分高密度二维单元。文中给出了代表奇异性应力场强度的夹杂角部广义应力强度因子数值解,并考虑材料属性、夹杂尺寸和夹杂位置关系的影响。算例中,考虑了夹杂和基体完全接合的情况,并给出了考核例。结果表明:当前模型能得到高精度数值解,且收敛性好;与传统有限元法和积分方程方法相比,该模型更具有通用性,为非均质材料的细观力学分析打下了基础。 相似文献
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本文研究裂纹和夹杂互相干涉的弹性力学的平面问题.一对位错和一对集中力的格林函数被分别用以形成裂纹和夹杂.所得积分方程适合于任意相对方位和尺寸的一个裂纹和一个夹杂.文中描述了裂纹尖端附近应力场的奇异性.对夹杂尖端附近应力场的奇异性给了特别的注意,并为夹杂尖端的应力强度因子作了定义.对各种不同的裂纹夹杂几何情况和不同的夹杂刚度作了数值计算.根据这些数值结果——裂尖和夹杂尖端的应力强度因子,分析、讨论了裂纹夹杂的各种几何参数以及夹杂-母体材料刚度比对裂纹-夹杂互相干涉效应的影响. 相似文献
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基于一种特殊有限元特征分析方法获得两相材料界面端奇异性应力和位移场数值特征解, 据此开发了一种新型超级单元模型, 用于分析热载荷作用下两相材料界面端的应力场. 与机械载荷作用下超级单元模型的区别在于, 该模型在能量泛函中考虑了热-机耦合的影响, 将应力场分为奇异项和非奇异项, 而奇异性项又可分解为热致部分和力致部分. 模型的有效性通过了经验解和传统有限元方法的验证;模型可以避免在界面端邻域网格高度加密, 提高了计算速度, 对于分析多奇异性点应力干涉问题有重要意义. 相似文献
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论文给出了一种分析椭圆类夹杂周边应力场的新型杂交应力有限元方法.基于弹性力学中平面问题的Muskhelishvili复势方法,应用保角变换映射技术,以Laurent级数和Faber级数为工具,借助Hellinger-Reissner原理构建一个能够反映椭圆类夹杂周边弹性现象同时包含椭圆夹杂的多边形超级单元.将该超级单元与标准的4结点杂交应力单元耦合在一起即可建立一种分析椭圆类夹杂周边弹性场的新型特殊杂交应力有限元方法.文中考核算例表明:该文方法不但使用简单、有效,而且精度高、单元少.作为论文方法的一个拓展应用,文章最后给出了一个分析含二个椭圆夹杂无限大各向同性板在远场均布载荷作用下椭圆夹杂周边弹性场的算例,并讨论了椭圆夹杂间距和弹性刚度比对应力集中系数的影响. 相似文献
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Meng-Cheng Chen Xue-Cheng Ping 《International Journal of Solids and Structures》2009,46(13):2527-2538
This paper deals with the inplane singular elastic field problems of inclusion corners in elastic media by an ad hoc hybrid-stress finite element method. A one-dimensional finite element method-based eigenanalysis is first applied to determine the order of singularity and the angular dependence of the stress and displacement field, which reflects elastic behavior around an inclusion corner. These numerical eigensolutions are subsequently used to develop a super element that simulates the elastic behavior around the inclusion corner. The super element is finally incorporated with standard four-node hybrid-stress elements to constitute an ad hoc hybrid-stress finite element method for the analysis of local singular stress fields arising from inclusion corners. The singular stress field is expressed by generalized stress intensity factors defined at the inclusion corner. The ad hoc finite element method is used to investigate the problem of a single rectangular or diamond inclusion in isotropic materials under longitudinal tension. Comparison with available numerical results shows the present method is an efficient mesh reducer and yields accurate stress distribution in the near-field region. As applications, the present ad hoc finite element method is extended to discuss the inplane singular elastic field problems of a single rectangular or diamond inclusion in anisotropic materials and of two interacting rectangular inclusions in isotropic materials. In the numerical analysis, the generalized stress intensity factors at the inclusion corner are systematically calculated for various material type, stiffness ratio, shape and spacing position of one or two inclusions in a plate subjected to tension and shear loadings. 相似文献
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本文采用编制的有限元程序求解了无限大板中含有单个具有角点的刚性夹杂在无限远处均布外载作用下夹杂角点附近的位移场,并结合Inshikawa的工作,求得了相应的应力强度因子。在此基础上,着重分析了两个刚性夹杂间的相互作用,得到了双夹杂左右角点附近的KⅠ,Ⅱ值随夹寻间距离改变而变化的规律。 相似文献
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本文采用了一种基于不连续场修正权函数的无网格方法来处理二维平面多裂纹问题。相较于传统的无网格断裂不连续场和奇异场模拟方法,修正权函数法算法简便易实现。采用修正权函数处理多裂纹时,只需要对每一段裂纹周围节点的权函数进行修正,就能同时模拟多裂纹不连续位移场和多裂尖奇异场。本文采用基于不连续场修正权函数的无单元Galerkin方法(EFGM),对Y型裂纹板、十字型裂纹板和孔边双裂纹板进行了分析。数值结果表明,在不引入扩展基函数情况下,通过修正权函数法能够得到精度较高的应力强度因子解,能较好地拟合多裂纹的裂尖奇异场。 相似文献
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Yoshiaki Nomura Toru Ikeda Noriyuki Miyazaki 《International Journal of Solids and Structures》2010,47(14-15):1775-1784
A numerical method using a path-independent H-integral based on the conservation integral was developed to analyze the singular stress field of a three-dimensional interfacial corner between anisotropic bimaterials under thermal stress. In the present method, the shape of the corner front is smooth. According to the theory of linear elasticity, asymptotic stress near the tip of a sharp interfacial corner is generally singular as a result of a mismatch of the materials’ elastic constants. The eigenvalues and the eigenfunctions are obtained using the Williams eigenfunction method, which depends on the anisotropic materials’ properties and the geometry of an interfacial corner. The order of the singularity related to the eigenvalue is real, complex or power-logarithmic. The amplitudes of the singular stress terms can be calculated using the H-integral. The stress and displacement around an interfacial corner for the H-integral are obtained using finite element analysis. In this study, a proposed definition of the stress intensity factors of an interfacial corner, which includes those of an interfacial crack and a homogeneous crack, is used to evaluate the singular stress fields. Asymptotic solutions of stress and displacement around an interfacial corner front are uniquely obtained using these stress intensity factors. To prove the accuracy of the present method, several different kinds of examples are shown such as interfacial corners or cracks in three-dimensional structures. 相似文献
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IntroductionOfallthefiber_reinforcedcompositematerials,theshort_fibercompositematerialnotonlystrengthensthematrixbutavoidsdefectionsofthelong_fibercompositematerialaswell.Themicro_mechanicsaboutitsuchasfracture ,fatigueanddamageisverycomplex .Intheprevi… 相似文献
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IntroductionUptonow ,thetechnicalliteratureonseparatecracks,voids,inclusionsandtheinteractionsbetweencracksandinclusionshavebeenquiteextensive.However,thecontactproblemsofcrack_inclusiondonotseemtobeaswidelystudied .Thispapercanberegardedasthefurtherrese… 相似文献