Omori Ryo
Fundamental research on hammering test using a cellular automaton method
Miyaki Yasuyuki
While the periodic inspection for the structure is important, focusing on hammering test in the present study, we investigated using the CA program the usefulness of it.
CA program used in this study do not fully support the principles of the hammering test. Therefore, we set in the 15 ¡ß 40 ¡ß 15 cell specimens of rectangular model, by paying attention to the cells of a certain one, were compared in the presence or absence of a defect the pressure variation with respect to the elapsed time. I think the difference is when you are recognized in the presence or absence of a defect, the usefulness of hammering test is can be evaluated.
I set the boundary conditions per the analysis. First, when using the cells of the full transmission, rapid damping was observed were determined to be unsuitable. Next, the place of using the cells fully reflective, damping is not confirmed most cases, this is not suitable. Therefore, when it is set by adding a condition to the cells of the full reflection, transmission energy of 1%, and reflects 99%, and shows the behavior of the pressure variation with an attenuation that is equal to the measured value of the hitting sound experiments were. So, an analysis was conducted using the boundary conditions described above.
Installation of the defect to the model was performed four patterns by changing the shapes and sizes. Did not change much for small defects but, in the case of large defects, changes were observed in the damping and the initial value of the pressure. Even when looking at the entire surface, in each processing, differences of pressure variation was observed.
In conclusion, the pressure fluctuation, that when comparing the presence or absence of a defect, it is possible to perform comparisons equal to the measured value of sound is confirmed, the usefulness of the hammering test has confirmed that point. As a challenge, adding the conditions to improve the CA program, fully support the principles of hammering test, and the like. Further, it is possible to obtain data of the actual value of the specimen with the specimen, the sound known defects is also important.
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