Impact dynamic pipe fracture by waterhammer

Yukio Kono, Kazumi Ishikawa, Akira Haga, Kazuo Kato

Thursday 2 july 2015

14:50 - 15:05h at South America (level 0)

Themes: (T) Water engineering, (ST) Experimental facilities and instrumentation

Parallel session: 12C. Engineering - Industrial

The dynamic fracture and the impact fracture became more significant study after the Great North Japan Earthquake occurred on 11th of March, 2011. Many concrete and steel structures which we believed strong were destroyed very easily because the structures are designed by static strength of materials. The water main is destroyed by waterhammer. Waterhammer occurs by sudden valve closure at the time of earthquake. The study of “Variation of strength by quasi-static and dynamic fracture of PVC pipes” already published in previous conferences. It has only a few studies on impact fracture which destroyed quickly faster than dynamic fracture. The three dimensional equation of motion in cylindrical coordinates is considered to find the work done by dynamic stress and strain curves and the work done by the kinetic effect which is work done by acceleration. The kinetic work is zero when the loading time to the pipe material is comparatively slow even it is dynamic loading. However it changes to great amount after loading speed, in another word strain velocity becomes very high speed.