Elastic-Plastic Analysis of Hydride Blisters in Zircaloy-2 Pressure Tubes

1988 ◽  
Vol 110 (3) ◽  
pp. 276-282 ◽  
Author(s):  
Y. J. Kim ◽  
M. L. Vanderglas

The possibility that stresses might be produced as a consequence of expansion resulting from the transformation of zirconium to zirconium hydride in the form of blisters was investigated. Parametric elastic-plastic finite element analyses were performed because the physical properties near the blister were not clearly defined. Results show that significant stresses can arise from the volume expansion of hydride blisters, being largely compressive within the blister, tensile outside.

Author(s):  
K. M. Prabhakaran ◽  
S. R. Bhate ◽  
V. Bhasin ◽  
A. K. Ghosh

Piping elbows under bending moment are vulnerable to cracking at crown. The structural integrity assessment requires evaluation of J-integral. The J-integral values for elbows with axial part-through internal crack at crown under in-plane bending moment are limited in open literature. This paper presents the J-integral results of a thick and thin, 90-degree, long radius elbow subjected to in-plane opening bending moment based on number of finite element analyses covering different crack configurations. The non-linear elastic-plastic finite element analyses were performed using WARP3D software. Both geometrical and material nonlinearity were considered in the study. The geometry considered were for Rm/t = 5, and 12 with ratio of crack depth to wall thickness, a/t = 0.15, 0.25, 0.5 and 0.75 and ratio of crack length to crack depth, 2c/a = 6, 8, 10 and 12.


1993 ◽  
Vol 115 (2) ◽  
pp. 227-236 ◽  
Author(s):  
M. Yu ◽  
B. Moran ◽  
L. M. Keer

A direct approach for elastic-plastic analysis and shakedown is presented and its application to a two-dimensional rolling contact problem is demonstrated. The direct approach consists of an operator split technique, which transforms the elastic-plastic problem into a purely elastic problem and a residual problem with prescribed eigenstrains. The eigenstrains are determined using an incremental projection method which is valid for nonproportional loading and both elastic and plastic shakedown. The residual problem is solved analytically and also by using a finite element procedure which can be readily generalized to more difficult problems such as three-dimensional rolling point contact. The direct analysis employs linear-kinematic-hardening plastic behavior and thus either elastic or plastic shakedown is assured, however, the phenomenon of ratchetting which can lead to incremental collapse, cannot be treated within the present framework. Results are compared with full elastic-plastic finite element calculations and a step-by-step numerical scheme for elastic-plastic analysis. Good agreement between the methods is observed. Furthermore, the direct method results in substantial savings in computational effort over full elastic-plastic finite element calculations and is shown to be a straightforward and efficient method for obtaining the steady state (shakedown) solution in the analysis of rolling and/or sliding contact.


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