Fundamental Research on the Impact Damages and the Evaluation of Residual Strength of Fiber Reinforced Laminated Plates

碳纤维增强塑料（CFRP）层合结构广泛应用于涡轮转子、飞机机身和空间结构等运动体的结构构件。这些结构的主要问题之一是异物损伤（FOD）和损伤部位的残余强度。本文研究了单向预浸料对CFRP叠合板的冲击损伤。CFRP平板在低速下受到硬冲击和软冲击的正常冲击。研究了损伤试样的冲击损伤特征和疲劳残余强度。本研究的主要成果总结如下：1。通过超声显微镜、光学显微镜和扫描电子显微镜的观察，明确了硬、软冲击体对CFRP层合板的损伤模式特征。脱层的总面积与冲击能量成正比。提出了获得叠合板动态载荷-挠度曲线的实验方法。然后，对复合材料的吸收能进行了定量评价。损伤试件的三点弯曲和四点弯曲疲劳试验表明，损伤的扩展机制存在显著差异。在各向异性板理论和各向异性三维理论的情况下，提出了层合板冲击响应的分析方法。这些方法将有助于弄清层合板冲击损伤的机理。

Laminated structures of the carbon fiber reinforced plastics (CFRP) are widely used as structural members of the moving bodies such as rotors of the turbine, the fuselage of the air plane and the space structure. one of the major problem of these structures is the foreign object damage (FOD) and the residual strength of the damaged parts.In this research, the impact damages of CFRP laminated plates by the uni-directional prepreg are studied. The CFRP flat plates are impacted normally by the hard and the soft impactors with low velocities. The features of the impact damages and the fatigue residual strength of the damaged specimen are investigated.Main results of this research are summarized as follows :1. For the collision of the hard and the soft impactors to CFRP laminates, the features of the damaged patterns became clear from the observations with the ultrasonic microscope, the optical microscope and the scanning electronic microscope.2. The total area of the delanination is proportional to the impact energy.3. The experimental method to obtain the dynamic load-deflection curve for the laminated plates is developed. Then, the absorbed energies of the laminates were evaluated quantitatively.4. For the three point bending and the four point bending fatigue tests of damaged specimens, it is shown that there is a significant difference to the mechanism of the propagations of the damages.5. Analytical methods of the impact responses for laminated plates are developed in cases of the anisotropic plate theory and the anisotropic three dimensional theory. These methods would be utilized to clear the mechanism of the impact damages of laminates.