Fracture Mechanics Approach to the Interaction Between Fiber and Matrix in Composite Materials.

复合材料中纤维与基体相互作用的断裂力学方法。

基本信息

批准号：
60550041
负责人：
TAKAO Yoshihiro
金额：
$ 1.22万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60550041/
关键词：
Composite Materials Crack Delamination Debonding Stress Intensity Factor Toughness Fracture Short Fiber

项目摘要

1. The damage model with shear resistance along the fiber-matrix boundary was applied to the microscopic failure processes in composite materials using the shear lag analysis. The focused materials were the broken fiber reinforced composites, hybrid composites, and short fiber composites. The effects of the geometrical and material constants were obtained. One of the interesting results is as follows. If the Griffith type of energy equation is the dominant condition for the propagation of debonding, it propagates gradually at first and beyond some critical value of debonding length it propagates catastrophically to the final failure of short fiber composites. This critical value is dependent on both the fiber aspect ratio and the Young's modulus ratio.2. Three-dimensional elastic analysis was applied to the interaction between the fiber and crack in composite materials. The integral equation was formulated to yield the effect of fiber on the stress intensity factor of a penny shaped cr … More ack in composite materials under Mode <III> loading. The nearest fibers have the dominant effect on the stress intensity factor than any other fiber.3. An approximate analytical solution was obtained for the microscopic stress distribution in unidirectional composites. It has strong relation to the debonding and shear resistance between the fiber and matrix. The increased fiber volume fraction was found to change the normal stress at the boundary from the compressive to tensile one in the real composite system under axial tensile loading.4. An numerical process to treat the integral equation for the T-shaped crack was found to yield the resonable stress intensity factor of the boundary crack between different materials.5. The experimantal models for the above 2 and 4 were made to insure the analytical solutions. A Charpy type impact test was performed to obtain the fracture mode and energy in case of 2. The caustic method was used to obtain the stress intensity factor at the debonding tip in case of 4. Less

1. 使用剪切滞后分析将沿纤维基体边界的抗剪损伤模型应用于复合材料的微观失效过程，重点研究了断裂纤维增强复合材料、混合复合材料和短纤维复合材料的影响。得到的一个有趣的结果如下：如果格里菲斯型能量方程是脱粘传播的主要条件，那么它首先会逐渐传播，并超过脱粘长度的某个临界值。它会灾难性地传播到短纤维复合材料的最终失效。这个临界值取决于纤维的长径比和杨氏模量比。2．将三维弹性分析应用于复合材料中纤维和裂纹之间的相互作用。积分方程的制定是为了得出在模式 <III> 载荷下纤维对复合材料中便士形 cr 应力强度因子的影响，最近的纤维比任何其他纤维对应力强度因子具有主导作用。 .3. 近似值获得了单向复合材料中微观应力分布的解析解，它与纤维和基体之间的脱粘和剪切阻力密切相关，发现纤维体积分数的增加使边界处的法向应力从压缩应力变为拉伸应力。 4．建立了T形裂纹积分方程的数值计算方法，得到了不同材料间边界裂纹的合理应力强度因子。5．多于进行图2和图4以确保解析解，进行夏比冲击试验以获得情况2的断裂模式和能量。采用苛性碱法获得情况4的脱粘尖端处的应力强度因子。较少的