抄録
Rabbit patellar tendon-bone complex specimens were subjected to impact tensile load to simulate the sports accident. During the tests, microdamage initiation and accumulation process in tendon was monitored using acoustic emission (AE) technique. In addition, in-situ observation from vertical and horizontal directions using two high-speed cameras was carried out to determine the strain distribution. The stress increased monotonically to the ultimate tensile stress (UTS), which was significantly higher than the static tests. Despite of the extremely short time, a number of AE signals were detected continuously before the UTS. Furthermore, AE signals were emitted in the area where the local strain increased significantly in the strain distribution of the surface. It is then demonstrated that AE technique enables not only the detection of invisible microdamage but the identification of the damage location. It is worth nothing that the amplitudes of detected AE signals were much higher than static tests. Since AE amplitude corresponds to the magnitude of individual microdamage, it is suggested that larger magnitude of individual microdamage is initiated under impact tensile load. Consequently, it is demonstrated that AE technique has a possibility of clarifying the detailed rupture mechanism of tendon or ligament under impact load.
