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Shock and Vibration
Volume 3, Issue 5, Pages 373-387

Parametric Nonlinear Finite Element Analysis of Strain Ratcheting in Pressurized Elbows Based on Random Vibration

Yong Zhao,1 John D. Stevenson,2 and H.T. Tang3

1Engineering Mechanics Group, Battelle Memorial Institute, 505 King Avenue, Columbus, OH 43201, USA
2Stevenson and Associates, 9217 Midwest Avenue, Cleveland, OH 44125, USA
3Electric Power Research Institute, Department of Nuclear Safety, PO Box 10412, Palo Alto, CA 94303, USA

Received 10 January 1996; Accepted 27 March 1996

Copyright © 1996 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The large strain ratcheting in cyclic plasticity of a typical pressurized pipe elbow in a realistic nuclear piping system was investigated in a more quantitative manner than previously. The elbow was modeled using a fine mesh of shell elements that can provide the completed information of detailed time varying strain distributions in the whole elbow area. The nonlinear time history stress analyses performed were based on a pseudostatic concept using the vector-valued stochastic displacement response time series loaded at the elbow ends. The response time series were synthesized using a simulation approach based on the random vibration analyses of the piping system and its supporting building. After a finite element mesh convergence study, parametric analyses were conducted that included the effects due to the magnitude changes in excitation level, internal pressure, material yield stress, and material strain hardening.