INCREMENTAL PLASTIC STRAIN OF A PIPE ELBOW WITH VARYING BEND RADII
by John C. Stearns *
Paul C. Lam ** Rudolph J. Scuvuzzo ***
* Graduate student, The Department of Mechanical
Engineering, The University of Akron, Akron, Ohio, USA
** Assistant Dean, College of Engineering, The University of Akron, Akron, Ohio, USA
*** Associate Dean, College of Polymer Science and Polymer Engineering, The University of Akron, Akron, Ohio, USA
ABSTRACT
The objective of this paper is to investigate the relationship between a elbow's bend radius and the magnitude of incremental plastic strain, or what is commonly called ratcheting in pressurized elbows subjected to cyclic bending loads. The effective or Von Mises stress must exceed the yield point before any ratcheting can occur. In this paper, ratcheting was studied using the elastic-plastic finite element code (ABAQUS [8]). A closed form elastic solution by Dodge and Moore was used to verify stresses calculated with the ABAQUS elbow element.
In addition, non-linear finite element analysis was preformed for a 3" and 6" bend radii. From the results, the trends between the elbows' bend radius and ratcheting effect can be evaluated.