FINITE ELEMENT MESH SIZE IN FATIGUE LIFE EFFECT

Abstract

Pipe elbows are consequential parts in a piping system. When a thin-wall elbow is exposed to variable amplitude loading as internal cyclic pressure, piping elbows are vulnerable to crack at the crown. This paper presents a technique to predict the fatigue life of elbows with the application of variable amplitude loadings  (VAL). For this goal, the finite element analysis technique was being used for the modeling and simulation. The fatigue life prognostication was carried out using the finite element based fatigue analysis codes. Numerical life prognostication results of three types of elbows (135o ,45o and curved ) under VAL are presented and discussed. Varying elbows shows different fatigue life behavior, the curved one gives better life. The two types of elements (Tet4 and Tet10) were investigated with optimum mesh size to get the maximum principle stress. The simulation results showed that more studies on the piping elbows necessity to be performed in order to obtain more delicate fatigue life