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基于ANSYS参数化设计语言(ANSYS parametric design language,APDL)采用规则六面体单元建立参数化的三维四向编织预制件网格模型。提出增强相单胞网格提取算法,实现三维四向编织复合材料增强相参数化单胞网格模型的提取。在增强相单胞网格提取算法中,针对单胞边界面与单元的相对位置关系归纳出的单元分割情况共有36种,其中六面体14种、三棱柱19种、四面体3种。基于Fortran语言编写单元提取和再重组程序,通过ANSYS代码数据库接口实现Fortran程序与ANSYS软件间高效的数据传递。计算纱线填充因子对三维四向编织复合材料单胞纤维体积分数的影响关系。联合区域叠合技术与增强相单胞网格提取算法,通过施加应力加载的周期性边界条件,预测三维四向编织复合材料的弹性性能,数值预测结果与试验吻合较好,并进一步得出编织角和纤维体积分数对三维四向编织复合材料弹性性能的影响规律。 相似文献
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根据复合材料宏观有效模量的定义,本文通过在复合材料细观模型的边界施加六组特定形式的均匀边界条件,以三维有限元作为数值分析手段,对各种细观模型及增强相力学特性,可一次性全部解出复合材料的所有弹性系数.通过计算典型代表体元细观模型,验证了本文数值方法的准确性和优越性. 相似文献
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三维四向编织复合材料弹性性能细观分析 总被引:4,自引:1,他引:4
从四步法 1× 1编织复合材料细观结构的代表性单胞模型入手 ,将预成形件划分为三个不同的区域 ,识别预成形件的两种局部单胞 (内部单胞和表面单胞 )模型 ,将单胞中的四个不同方向的纤维束看成是空间四个不同方向的单向复合材料 ,纤维束的性能可以等价于单向复合材料的宏观性能。采用复合材料中的细观力学分析方法 ,计算单向复合材料的弹性常数。认为每一纤维束的纤维体积含量与整个单胞的纤维体积含量相等。研究了三维编织复合材料代表性单胞模型的弹性常数预测 ,探寻三维编织工艺参数与力学性能之间的关系 ,利用刚度体积平均概念 ,预测三维四向编织复合材料的弹性常数 ,理论值与试验值取得了理想的吻合。 相似文献
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基于区域叠合技术和与材料断裂能相关的损伤演化模型对三维四向编织复合材料的渐进损伤演变过程及拉伸强度进行数值预测。结合基于Fortran语言编写的单胞增强相网格提取算法,实现了参数化单胞增强相网格模型的快速建立。基于Murakami损伤理论建立了正交各向异性损伤本构模型,利用等价位移控制相应模式下损伤的演变发展,分别模拟了典型大小编织角三维四向编织复合材料的细观损伤起始、扩展和最终失效过程。数值预测结果与实验结果吻合较好。 相似文献
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织物增强复合材料弹性常数的有限元法预测 总被引:1,自引:0,他引:1
根据织物增强复合材料的几何特征参数,采用三维卷曲模型建立了不同机织方式的织物增强复合材料代表性体积单元的几何模型;基于复合材料宏观有效模量的定义,对细观模型施加6组独立的均匀应变边界条件,建立相应的有限元模型,分析得到相应的细观应力场结果,再计算出织物增强复合材料的工程弹性常数。结果表明:有限元预测的结果与试验结果值吻合较好,验证了预测方法的有效性。 相似文献
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颗粒增强复合材料微结构的数值模拟与虚拟失效 总被引:2,自引:1,他引:1
利用材料微观组织结构仿真软件ProDesign生成的颗粒增强复合材料微结构样本,包含大量的Voronoi晶粒与椭球颗粒,被用于模拟真实的复合材料微结构,以研究各向异性与局域性对复合材料微结构力学性能的影响。通过对商业有限元软件ABAQUS的二次开发实现对颗粒增强复合材料微结构细观应力的数值计算。计算机模拟试验证实,增强相颗粒与基体材料的刚度不匹配以及材料微结构组成物取向的局部各向异性,对复合材料结构弱点的分布具有决定性的作用。同时,该计算试验结果对于评估微裂纹的启裂、扩展,预测复合材料微结构材料损伤后的材料性能,推演微结构"虚拟失效行为"亦具有十分重要的意义。 相似文献
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Aluminium-based composites, reinforced with low volume fractions of whiskers and small particles, have been formed by a powder route. The materials have been tested in tension, and the microstructures examined using transmission electron microscopy. The whisker composites showed an improvement in flow stress over the particulate composites, and this was linked to an initially enhanced work-hardening rate in the whisker composites. The overall dislocation densities were estimated to be somewhat higher in the whisker composites than the particulate composites, but in the early stages of deformation the distribution was rather different, with deformation in the whisker material being far more localized and inhomogeneous. This factor, together with differences in the internal stress distribution in the materials, is used to explain the difference in mechanical properties. 相似文献
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A general incremental micromechanical scheme for the nonlinear behavior of particulate composites is presented in this paper. The advantage of this scheme is that it can reflect partly the effects of the third invariant of the stress on the overall mechanical behavior of nonlinear composites. The difficulty involved is the determination of the effective compliance tensors of the anisotropic multiphase composites. This is completed by making use of the generalized self-consistent Mori–Tanaka method which was recently developed by Dai et al. (Polymer Composites 19 (1998) 506–513; Acta Mechanica Solida 18 (1998) 199–208). Comparison with existing theoretical and numerical results demonstrates that the present incremental scheme is quite satisfactory. Based on this incremental scheme, the overall mechanical behavior of a hard-particle reinforced metal matrix composite with progressive particle debonding damage is investigated. 相似文献
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An important class of short-fiber reinforced composites is the sheet molding compound, which is recently developed and currently
used in many engineering applications. Fatigue failure of the composites is a subject of major concern in design and cyclic
crack propagation is of particular significance in the fatigue life prediction of short fiber composites. However, research
on the fatigue behavior of polymer injection weld, especially short glass fiber-filled polymer injection weld, has not been
carried out. In this study the analyses of the fatigue crack growth behaviors at weld line and in the bulk are performed based
on low cycle fatigue test. 相似文献
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Several engineering components made of carbon-based heat-resistant composites are subjected to severe erosive wear. In view of the above, the solid particle erosion behavior of two and four dimensionally reinforced carbon/carbon (C/C) composites as well as that of carbon/phenolic (C/P) composite has been characterized at the ambient temperature. The investigated C/C composites have been produced through a liquid-phase infiltration method followed by hot isostatic pressing, while the C/P composite prepegs have been cured inside an autoclave. The erosion rates of these composites have been determined for two different impact angles and two different impact velocities using silica sand with average particle diameter of 200 μm. The morphologies of as-received and eroded surfaces of test specimens have been examined with the help of scanning electron microscopy to understand the mechanism of material removal. The erosion response, erosion efficiency, and erosion micromechanisms of these composites have been studied in detail. While the erosion resistance of the C/P composite is found to be superior to that of the investigated C/C composites, the four dimensionally reinforced C/C composite have shown the highest erosion efficiency. All the composites have exhibited a semi-ductile erosion response. Their mechanical properties have little correlation with the erosion rates. 相似文献
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Rupa Dasgupta 《Tribology International》2010,43(5-6):951-958
One of the advantages reported in Al-base alloy particulate composites is its improved sliding wear properties over its base alloy by several investigators. Much of the improvement depends on the experimental conditions, alloy composition as on the particulate size, shape and distribution in the matrix. The present paper will make an attempt to assess the improvement in sliding wear properties attained in a few Aluminium base alloys with different size, quantity and distribution of SiC-particulates and bring out the efficacy of making composites if any in the different alloy systems over other methods of property improvement like homogenisation, secondary processing, etc. In some cases remarkable improvements have been achieved, such as the composites have sustained much harsher conditions whereas the base alloy has seized at much milder conditions; whereas in other alloy systems the improvement is only comparable to that obtained by secondary processing. Properties attained on homogenisation, extrusion and making composites would be compared with the base alloys. In this paper an attempt will be made to draw a line as to the conditions under which composites can been used to make engineering products where improved sliding wear resistance is demanded and where more prevalent methods like ageing could serve the purpose. 相似文献
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High strength, light weight, ease of fabrication, excellent castability, and good wear resistance make aluminum alloy composites suitable for commercial applications. In this work, a silica-rich ash particle (palmyra shell ash) was reinforced with aluminum alloy (AlSi10Mg) composites and its mechanical and tribological properties were studied. The aluminum alloy was reinforced with 3, 6, and 9 wt% of palmyra shell ash particles, and its dry sliding wear behavior was studied using a pin-on-disc machine under different loading conditions. The result shows that the dry sliding wear resistance of Al–palmyra shell ash composites was almost similar to that of fly ash– and rice husk ash–reinforced Al-alloy composites and these composites exhibit better wear resistance compared to unreinforced alloy. The palmyra shell ash particle weight fraction significantly affects the wear and friction properties of the composites. Scanning electron microscopic examination of the worn surface reveals that at various loads palmyra shell ash particles act as load-bearing constituents and the wear resistance of the reinforced palmyra shell ash with a size range of 1–50 µm was superior to that of unreinforced alloy. Mechanical properties (hardness and tensile strength) were also studied and it was observed that the reinforced Al-alloy showed a significant increase in mechanical properties. 相似文献
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In this work, the tribological behavior of micrometer and submicrometer cenosphere particulate–filled E-glass fiber–reinforced vinylester composites have been investigated on a pin-on-disc tester under dry sliding and water-lubricated sliding conditions. Three different uniform sizes of cenosphere particles (2 μm, 900 nm, 400 nm) were used as fillers in the glass fiber–reinforced vinylester composites. The weight fraction of cenosphere particles has been varied in the ranges from 5, 10, 15, to 20 wt%. The experimental results show that all of the composites exhibited lower coefficient of friction and lower wear resistance under water-lubricated sliding conditions than under dry sliding. It has been noted that the submicrometer size (400 nm) cenosphere particulates as fillers contributed significantly to improve the wear resistance. It has also been noted that 10 wt% of the cenosphere particles is the most effective in reducing the wear rate and coefficient of friction. Effects of various wear parameters such as applied normal loads, sliding speeds, particle size, and particle content on the tribological behavior were also discussed. In order to understand the wear mechanism, the morphologies of the worn surface were analyzed by means of scanning electron microscopy (SEM) for composite specimens under both dry and water-lubricated sliding conditions. 相似文献
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Fiber reinforced polymer (FRP) composites exhibit nonlinear and hyperelastic characteristics under finite deformation. This
paper investigates the macroscopic hyperelastic behavior of fiber reinforced polymer composites using a micromechanical model
and finite deformation theory based on the hyperelastic constitutive law. The local stress and deformation of a representative
volume element are calculated by the nonlinear finite element method. Then, an averaging procedure is used to find the homogenized
stress and strain, and the macroscopic stressstrain curves are obtained. Numerical examples are given to demonstrate hyperelastic
behavior and deformation of the composites, and the effects of the distribution pattern of fibers are also investigated to
model the mechanical behavior of FRP composites. 相似文献