A New Approach of Piping Dynamic Response Considering Plastic Effect

Dynamic response of piping system is significantly affected by plastic deformation. Based on the behavior classification of the pipe subjected to a steady axial force and a cyclic bending moment, the absorbed energy per semi-cycle due to plasticity is calculated for different elasto-plastic behavior. A new efficient piping dynamic response analysis method, plastic dissipation equivalent damping method, is proposed to consider the plastic effect on the basis of equivalence principle of energy dissipation. The proposed scheme is implemented in the finite element analysis code FEAP by introducing the equivalent damping which causes the same energy loss per semi-cycle. Numerical examples indicate that the results obtained by the present method show good agreements with those of elasto-plastic FEM analysis, and that this method can reduce the required computational effort significantly.