CFRP のモードⅠおよびモードⅡ試験への AE 法によるき裂先端位置標定と損傷モード評価の適用

抄録

For the Double Cantilever Beam (DCB) and End Notched Flexure (ENF) test, it is necessary to measure the crack length to calculate fracture toughness in Mode-I and Mode-II, respectively. In this research, we proposed a new method to measure the crack length in the DCB and ENF tests by using the acoustic emission (AE) method, which can detect the cracking behavior. The crack tip positions were identified by the AE arrival time difference with removing noises and using the precise analyze method as the Akaike Information Criterion. As a result, the position of the crack tip obtained by the arrival time difference of the AE during the DCB test showed equal or more precise value than the position obtained by microscope observation, therefore, the AE method can be used for measurement of the crack tip position. In the ENF test, AE could observe the internal cracking behavior before the fracture, however, microscope observation could not catch that cracking behavior. Furthermore, the damage mode can be specified from the frequency analysis of the AE waveform measured during the DCB and ENF test. Consequently, our proposed method for DCB and ENF tests with the AE techniques is valuable.