共查询到19条相似文献,搜索用时 140 毫秒
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以修正的经典层合板理论为基础, 分析三维编织复合材料的力学性能。在单胞的长度方向积分和平均, 预测编织结构复合材料的有效弹性模量; 采用蔡-胡多项式失效准则, 得到三维编织复合材料的强度性能。另外, 进行编织结构复合材料的力学性能实验, 探讨纺织工艺参数, 如纤维编织角、横向编织角、轴向纱数与编织纱数之比、纤维体积含量等对力学性能的影响, 理论预报和试验结果进行对比, 发现该力学模型能较好地预报三维编织复合材料的刚度和强度性能。 相似文献
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有关三维编织复合材料的理论分析研究归纳为:基于细观结构几何模型的物理性能研究和力学性能研究两部分.纤维体积分数是物理性能研究的最主要参数,力学分析以复合材料的弹性性能为主.合理的几何模型决定了力学性能分析与试验结果的一致性.建立在代表性体积单元尺度的几何模型应用最为广泛,得到了力学性能的试验验证.三维编织复合材料的力学性能的数值仿真主要以有限元方法为主,然而仅仅依赖于对其弹性性能的研究结果还远远不能满足三维编织复合材料作为关键结构部件的使用要求,建立完善的断裂准则是编织复合材料大量使用的理论依据.特殊形状的一次性编织复合材料的力学性能研究有待进一步深入. 相似文献
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碳纤维三维编织复合材料的结构对拉伸和弯曲性能的影响 总被引:9,自引:0,他引:9
研究了碳纤维四步法三维四向、三维五向编织结构复合材料的拉伸和弯曲性能,以及结构参数-编织角的变化对其拉伸和弯曲性能的影响,并与层合复合材料作了对比性研究.结果表明,三维编织复合材料具有良好的力学性能,其拉伸强度可达810MPa、拉伸模量可达95.6GPa,弯曲强度可达829.03MPa、弯曲模量可达67.5GPa.同时,编织角和编织结构对复合材料性能有较大的影响.随着编织角的增大,复合材料的拉伸、弯曲强度和模量均减小;三维五向结构的拉伸、弯曲强度和模量均高于四向结构;在纤维体积含量相近的情况下,通过对编织角的设计,可以设计三维编织复合材料的性能. 相似文献
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三维编织复合材料因其结构整体性好、综合性能优异,已成为航天、航空、国防领域部分主承力构件和高功能制件的首选材料。然而,三维编织复合材料结构件在服役过程中不可避免地处于高温、低温或温度急剧变化等恶劣环境,由于三维编织复合材料增强体和基体热物理性能的巨大差异将严重威胁结构尺寸的稳定性及结构使用寿命。本文主要从实验、理论和数值仿真研究三方面,综述了近年来国内外对三维多向编织复合材料热物理性能和温度效应影响下力学性能的研究成果及研究进展。首先分析了现有研究中编织工艺、编织参数、环境温度、界面、缺陷等因素对三维多向编织复合材料热传导性能和热膨胀性能的影响规律。其次以细观结构、全尺寸、多尺度模型为主分析了不同结构几何模型的区别与联系。最后探讨了高、低温环境温度和不同载荷形式对三维多向编织复合材料组分材料损伤、失效形态及热力耦合行为的影响机制,并同时总结了现有研究工作中的重点与发展方向。 相似文献
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复合材料三维编织结构的单元体模型 总被引:18,自引:4,他引:18
复合材料三维编织结构技术是国外八十年代发展起来的高新纺织技术。三维编织结构复合材料是一种新型结构形式的复合材料,它具有优良的抗冲击损伤性能、力学性能和耐烧蚀性能。本文讨论了三维编织结构的单元体模型,推导出有关参数之间的数学关系。 相似文献
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Dian-sen Li Dai-ning Fang Zi-xing Lu Zhen-yu Yang Nan Jiang 《Applied Composite Materials》2010,17(4):389-404
In the first part of the work, we have established a new parameterized three-dimensional (3D) finite element model (FEM) which
precisely simulated the spatial configuration of the braiding yarns and considered the cross-section deformation as well as
the surface contact relationship between the yarns. This paper presents a prediction of the effective elastic properties and
the meso-scale mechanical response of 3D braided composites to verify the validation of the FEM. The effects of the braiding
parameters on the mechanical properties are investigated in detail. By analyzing the deformation and stress nephogram of the
model, a reasonable overall stress field is provided and the results well support the strength prediction. The results indicate
it is convenient to predict all the elastic constants of 3D braided composites with different parameters simultaneously using
the FEM. Moreover, the FEM can successfully predict the meso-scale mechanical response of 3D braided composites containing
periodical structures. 相似文献
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针对不同编织角度的三维四向编织碳纤维/环氧树脂复合材料,进行了热环境下的轴向拉伸和压缩力学性能实验研究,讨论了温度对三维四向编织复合材料的轴向拉伸和压缩力学性能的影响,并根据宏观断裂形貌和SEM图像分析了材料的破坏和断裂机制。结果表明,随着测试温度的升高,三维四向编织碳纤维/环氧树脂复合材料的纵向拉伸强度有小幅提高,而纵向压缩强度显著降低。在室温条件下,编织角对材料的纵向拉伸破坏特征没有影响,而对材料的纵向压缩破坏特征有较大影响。随着测试温度的升高,不同编织角度复合材料的纵向拉伸和压缩的损伤破坏形态均与室温条件下明显不同。 相似文献
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This study is concerned with the microstructural modeling and mechanical properties computation of three-dimensional (3D) 4-directional braided composites. Microstructure of the braided composite determines its mechanical properties and a precise geometry modeling of the composite is essential to predict the material properties. On the basis of microscopic observation, a new parameterized microstructural unit cell model is established in this paper. And this model truly simulates the microstructure of the braided composites. Furthermore, the mathematical relationships among the structural parameters, including the braiding angle, fiber volume fraction and braiding bitch, are derived. By using the unit cell model, the second-order two-scale (SOTS) method is applied to predict the mechanical properties of 3D 4-directional braided composites, including stiffness parameters and strength parameters. Besides, the effects of the braiding angle and fiber volume fraction on the elastic constants are investigated in detail. Numerical results show that the predictive stiffness and strength parameters are in good agreement with the available experimental data, which demonstrate that the established unit cell model is applicable and the second-order two-scale method is valid to predict the mechanical properties of 3D 4-directional braided composites. 相似文献
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Diantang Zhang Li Chen Ying Sun Yifan Zhang Kun Qian 《Applied Composite Materials》2017,24(5):1233-1250
A study is conducted with the aim of developing multi-scale analytical method for designing the composite helicopter arm with three-dimensional (3D) five-directional braided structure. Based on the analysis of 3D braided microstructure, the multi-scale finite element modeling is developed. Finite element analysis on the load capacity of 3D five-directional braided composites helicopter arm is carried out using the software ABAQUS/Standard. The influences of the braiding angle and loading condition on the stress and strain distribution of the helicopter arm are simulated. The results show that the proposed multi-scale method is capable of accurately predicting the mechanical properties of 3D braided composites, validated by the comparison the stress-strain curves of meso-scale RVCs. Furthermore, it is found that the braiding angle is an important factor affecting the mechanical properties of 3D five-directional braided composite helicopter arm. Based on the optimized structure parameters, the nearly net-shaped composite helicopter arm is fabricated using a novel resin transfer mould (RTM) process. 相似文献
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Li-li Jiang Guo-dong Xu Su Cheng Xia-mei Lu Tao Zeng 《Applied Composite Materials》2014,21(2):325-340
This paper presents a modified finite element model (FEM) to investigate the thermo-mechanical properties of three-dimensional (3D) braided composite. The effective coefficients of thermal expansion (CTE) and the meso-scale mechanical response of 3D braided composites are predicted. The effects of the braiding angle and fiber volume fraction on the effective CTE are evaluated. The results are compared to the experimental data available in the literature to demonstrate the accuracy and reliability of the present method. The tensile stress distributions of the representative volume element (RVE) are also outlined. It is found that the stress of the braiding yarn has a significant increase with temperature rise; on the other hand, the temperature change has an insignificant effect on the stress of the matrix. In addition, a rapid decrease in the tensile strength of 3D braided composites is observed with the increase in temperature. It is revealed that the thermal conditions have a significant effect on the strength of 3D braided composites. The present method provides an effective tool to predict the stresses of 3D braided composites under thermo-mechanical loading. 相似文献
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编织角是影响三维编织复合材料力学性能的最重要因素.实验数据表明:大编织角复合材料在单向拉伸作用下的破坏形式较为复杂,其应力-应变曲线呈现非线性特性.本文建立了细观应力场的均匀化列式和有限元求解方法,运用该方法对三维大编织角复合材料的细观应力分布进行了数值模拟,结合相关的强度理论对材料进行失效分析,并进一步对材料的拉伸强度进行预测.强度计算结果与实验结果较为吻合. 相似文献