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

1.将沿纤维-基体界面沿着具有剪切阻力的损伤模型应用于复合材料的细观破坏过程，并采用剪滞分析方法。重点介绍了断裂纤维增强复合材料、混杂复合材料和短纤维复合材料。得到了几何常数和材料常数对计算结果的影响。其中一个有趣的结果如下。如果Griffith型能量方程是短纤维复合材料脱粘扩展的主导条件，则脱粘首先逐渐扩展，超过某个临界脱粘长度后，脱粘将灾难性地扩展到最终破坏。该临界值取决于纤维的长径比和杨氏模量比。2.对复合材料中纤维与裂纹的相互作用进行了三维弹性分析。建立了积分方程，分析了纤维对硬币形钢的应力强度因子的影响 ...更多信息 复合材料在模态载荷作用下的裂纹<III>。最邻近的纤维对应力强度因子的影响最大.得到了单向复合材料细观应力分布的近似解析解。它与纤维与基体间的脱粘和抗剪强度有很强的关系。在轴向拉伸载荷作用下，纤维体积分数的增加使真实的复合材料界面处的正应力由压应力变为拉应力.通过对T型裂纹积分方程的数值处理，得到了合理的不同材料边界裂纹的应力强度因子.为保证解析解的正确性，对上述2和4项建立了实验模型。进行夏比型冲击试验以获得在2.采用焦散线法计算了4时脱粘尖端的应力强度因子。少

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