Coupling with the periodical displacement boundary condition,a representative volume element(RVE) model is established to simulate the progressive damage behavior of 2D1×1 braided composites under unidirectional ...Coupling with the periodical displacement boundary condition,a representative volume element(RVE) model is established to simulate the progressive damage behavior of 2D1×1 braided composites under unidirectional tension by using the nonlinear finite element method.Tsai-Wu failure criterion with various damage modes and Mises criterion are considered for predicting damage initiation and progression of yarns and matrix.The anisotropic damage model for yarns and the isotropic damage model for matrix are used to simulate the microscopic damage propagation of 2D1×1braided composites.Murakami′s damage tensor is adopted to characterize each damage mode.In the simulation process,the damage mechanisms are revealed and the tensile strength of 2D1×1braided composites is predicted from the calculated average stress-average strain curve.Numerical results show good agreement with experimental data,thus the proposed simulation method is verified for damage mechanism analysis of 2D braided composites.展开更多
为评价不同混杂结构复合材料冲击阻抗的混杂效应,通过引入芳纶纤维增强体制备了层间混杂(IE)、夹芯混杂(SA)、非对称混杂(US)和层内混杂(IA)的碳-芳纶二维编织复合材料,并通过落锤冲击实验研究了混杂结构对其冲击载荷、冲击吸收能量、...为评价不同混杂结构复合材料冲击阻抗的混杂效应,通过引入芳纶纤维增强体制备了层间混杂(IE)、夹芯混杂(SA)、非对称混杂(US)和层内混杂(IA)的碳-芳纶二维编织复合材料,并通过落锤冲击实验研究了混杂结构对其冲击载荷、冲击吸收能量、损伤形貌等性能的影响.实验结果表明:层内混杂(IA)试样具有最高的峰值载荷(4.28 k N),比非混杂结构层板高37.2%;其他混杂结构试样中,峰值载荷均低于非混杂结构层板,层板IE的韧性指数DI值比层板SA的高31.5%,说明层间混杂结构表现出比夹芯混杂结构优良的冲击韧性;但IA的弹性应变能(5.964 J)最大,其他试样弹性应变能(几乎为0)远小于试样IA,表明试样IA在冲击过程中产生了较大的弹性变形,表现出优良的韧性性能.通过超声扫描成像系统观察并评价层板内部冲击损伤及失效机理可知:碳纤维层板产生了较严重的内部损伤,试样SA和试样US侧面产生了分层现象;试样IE的C扫描图像显示试样产生了程度较轻的内部损伤,但和试样IA相比,其蓝色区域分布范围较大;IA试样冲击内部损伤面积较小,说明碳纤维和芳纶纤维相互交织排列的层内混杂结构,表现出较强的塑性变形能力和良好的抗冲击性能.展开更多
基金Supported by the National Natural Science Foundation of China(10672075)
文摘Coupling with the periodical displacement boundary condition,a representative volume element(RVE) model is established to simulate the progressive damage behavior of 2D1×1 braided composites under unidirectional tension by using the nonlinear finite element method.Tsai-Wu failure criterion with various damage modes and Mises criterion are considered for predicting damage initiation and progression of yarns and matrix.The anisotropic damage model for yarns and the isotropic damage model for matrix are used to simulate the microscopic damage propagation of 2D1×1braided composites.Murakami′s damage tensor is adopted to characterize each damage mode.In the simulation process,the damage mechanisms are revealed and the tensile strength of 2D1×1braided composites is predicted from the calculated average stress-average strain curve.Numerical results show good agreement with experimental data,thus the proposed simulation method is verified for damage mechanism analysis of 2D braided composites.
文摘为评价不同混杂结构复合材料冲击阻抗的混杂效应,通过引入芳纶纤维增强体制备了层间混杂(IE)、夹芯混杂(SA)、非对称混杂(US)和层内混杂(IA)的碳-芳纶二维编织复合材料,并通过落锤冲击实验研究了混杂结构对其冲击载荷、冲击吸收能量、损伤形貌等性能的影响.实验结果表明:层内混杂(IA)试样具有最高的峰值载荷(4.28 k N),比非混杂结构层板高37.2%;其他混杂结构试样中,峰值载荷均低于非混杂结构层板,层板IE的韧性指数DI值比层板SA的高31.5%,说明层间混杂结构表现出比夹芯混杂结构优良的冲击韧性;但IA的弹性应变能(5.964 J)最大,其他试样弹性应变能(几乎为0)远小于试样IA,表明试样IA在冲击过程中产生了较大的弹性变形,表现出优良的韧性性能.通过超声扫描成像系统观察并评价层板内部冲击损伤及失效机理可知:碳纤维层板产生了较严重的内部损伤,试样SA和试样US侧面产生了分层现象;试样IE的C扫描图像显示试样产生了程度较轻的内部损伤,但和试样IA相比,其蓝色区域分布范围较大;IA试样冲击内部损伤面积较小,说明碳纤维和芳纶纤维相互交织排列的层内混杂结构,表现出较强的塑性变形能力和良好的抗冲击性能.
