Vibration test of piping system

Japan is the prominent country in the world, where earthquakes occur frequently, and the demand of the safety and reliability of piping system in nuclear power plants and chemical plants against earthquakes has become strict year by year. In response to this, the method of dynamic aseismatic analysis has achieved rapid development together with the progress of computers. As the backup for the progress of such numerical analysis techniques, the vibration test of closer to the actual scale and actual earthquake loading condition has become necessary. For improving the accuracy of the calculation models, the support by vibration test is necessary. The accurate grasp of the vibration properties of piping system and the beforehand clarification of the behavior and breakdown mode of piping for the earthquake input at the design level or more by testing are useful for avoiding unnecessary aseismatic design. The method of applying vibration, the vibration measurement for piping system, the data processing, and the vibration test of a single mechanical snubber and a piping model supported with mechanical snubbers are reported. Even by simple methods such as vibrators or wire cut method, the vibration properties of piping system can be clarified to considerable extent. (Kako, I.)