Development of a Simple Impact Testing Machine for the Characterization of Ceramic Fiber Reinforced Ceramic Composites

1.本研究项目的主要目的是表征几种连续纤维增强陶瓷基复合材料(CFRC)的冲击断裂行为，并研制一种简易的测试装置来测试几种CFRC的冲击断裂特性。2.采用Split-Hopkinson压杆方法对CFRC进行了三点冲击弯曲试验。在数据记录系统上应用高通滤波装置成功地检测到了冲击断裂过程中试件的声发射。4.碳纤维增强氮化硅陶瓷复合材料的拉伸强度几乎与变形速率无关，而沿纤维方向的剪切强度随着变形速率的增加而显著增加。而Tirano纤维粘结陶瓷复合材料的拉伸强度和剪切强度随着变形速率的增加和试验温度的降低而显著提高。5.利用上述基本数据，试制了一台简单、小型的冲击试验机，并利用该试验机获得了某碳纤维混凝土弯曲断裂过程中的应力应变关系。

1.The main purpose of this research project is to characterize the impact fracture behavior of some continuous fiber reinforced ceramic matrix composites (CFRC), and to develop a simple testing apparatus for measurement of impact fracture characteristics of some kinds of CFRC.2.Three point impact bending tests on CFRC were carried out using split-Hopkinson pressure bar method, and smooth transmittted stress waves without high-frequency fluctuation were obtained to evaluate dynamic stress-strain relationships precisely by applying ramped incident waives.3.Acoustic emission from the test specimen during the impact fracture was also successfully detected by applying a high-pass filter device on the data recording system.4.Tensile strength of a carbon fiber reinforced silicon nitride ceramic composite was found almost independent of deformation rate, while shear strength along the orientated fiber direction was significantly increased with increase of deformation rate. On the other hand, the tensile and shear strength of a Tirano fiber bonded ceramic composite markedly increased with increase of deformation rate and decrease of testing temperature.5.By using the basic data above described, an impact testing machine with simple and small scale was made on a trial basis, and the machine was also applied to obtain stress-strain relations during bending fracture of some CFRC.