ANALYSIS OF THE WALL THICKNESS VARIATION OF PIPES UNDER INTERNAL PRESSURE

A computer simulation of the internal pressure expanding was  performed for pipes with uneven wall thickness made of steel, aluminum and titanium alloys. For this simulation software tool ESI Virtual-Performance 2016.0 was used that implements the finite element  method. The convergence and accuracy of the solution was estimated  by comparison with known solutions. A full factorial computational  experiment was performed by varying factors: the initial wall thickness variation of pipes, D/S and parameter of alloys hardening. The  regression equations were obtained by the internal pressure at the time  of destruction and final wall thickness variation from these factors. It  was found that the variation in wall thickness in the distribution pipe  rupture occurs in the thin wall. A wall with minimum thickness continues thinning with an almost constant maximum wall thickness, which  leads to an increase in the transverse variation in wall thickness. It was  concluded that the increase of the initial variation in wall thickness  pipe speeds up the process of rupture in the area of thin wall. It is recommended in conduits conducting high-pressure fluid to apply pipes  with minimal variation in wall thickness.