複数の局部重量をもつ円筒シェル模型の振動台実験とその解析

抄録

PURPOSE Authors have already reported an analytical method to calculate the dynamic behavior of axisymmetric shell structures with locally attached masses such as a steel containment vessel of nuclear power plants (Transactions of the A.I.J. No.338 April 1984). In this paper, the feasibility of the above analytical method is discussed through the simulation analysis to shaking table tests of a cylinder model which has locally several attached masses. VIBRATION TEST The test specimen is a steel cylinder attached thirteen concentrated masses (pressure-gage instruments and hanging hooks), and is fixed on the shaking table, to which the sinusoidal waves (1Hz〜70Hz) are input. As the test results, several resonant vibration modes are obtained including a beam type and some ovaling modes. The same test is also conducted in case of an additional weight attached to the mid-height of the cylinder. And a beam type and some ovaling modes are also obtained, but it's resonant peaks and frequencies are moved from the former ones. SIMULATION ANALYSIS At first, the axisymmetric free vibration modes are calculated by the finite element model without local masses. And next, the composit free vibration modes of the shell with local masses are obtained by Lagrange's equation superposing the above axisymmeteric modes. Finally, the forced vibration analysis is conducted by the mode superposition method using these modes. RESULT The analytical results show good agreement with the test results in respect of the resonant characteristics of the specimen for each case of the tests. Especially, the difference between two cases of the tests could be well followed by the analyses here.