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Futakawa, Masatoshi; Naoe, Takashi; Kogawa, Hiroyuki
Proceedings of 7th International Symposium on Impact Engineering (ISIE 2010) (CD-ROM), p.246 - 255, 2010/07
At the moment the proton beams are injected, thermal shock is occurred in the liquid metal and causes pressure waves. As a result, mercury cavitation is induced and damage is imposed along the interface between the liquid metal and the solid wall. Microbubbles are injected into the mercury to reduce the impact pressure waves. In the experiment, very rapid pressure rising, MPa/micro-sec, due to proton beam injection was simulated by electric discharge method to confirm the impact pressure reduction by the injected microbubbles. The reduction to 1/5 of the impact pressure without any bubbles was recognized under the condition of bubble size of 50 micro-meter in radius and 10
void fraction. The dynamic response of microbubbles was observed by an ultra highly speed camera with a frame rate of 1 million/sec. We confirmed the mitigation effect experimentally and theoretically, and predict the effect in mercury theoretically.
Kawai, Masayoshi*; Futakawa, Masatoshi; Naoe, Takashi; Xu, C.-N.*; Yamada, Hiroshi*
Proceedings of 7th International Symposium on Impact Engineering (ISIE 2010) (CD-ROM), p.380 - 385, 2010/07
We have proposed a sophisticated novel method of the SHB experiment to measure the time-dependent local strain distributions on a surface of the specimen by using mechanoluminescent materials combined with a high-speed camera and an image intensifier. The feasibility study was made for the aluminum specimens pasted with a typical mechanoluminescent material -Eu doped SrAl
O
film, in order to obtain the fundamental data for the method. Our results showed that SrAlO: Eu emitted lights as a response to the strain. Rise up of the light intensity was swift enough to follow the strain change due to HP impact. The luminescence intensity was experimentally verified and expressed as product of strain and strain rate. Accordingly, it can be said that this method gives a good tool for measuring time variation of local strain distributions.