Study of the Stress Distribution Around a Micro Hole on a Flexible Tube under Lateral Deflection with a Positive Rotation Angle Towards the Micro Defect

Objectives: This study was conducted for the effects of micro holes to stress distribution acting on bellows under lateral deflection with a positive rotation angle toward the micro defect. Methods/Statistical Analysis: Stress was analyzed by F.E.M. (Finite Element Method) and the chosen mesh consisted of 112,800 elements or more. Shell element and nonlinear method were used. The micro hole was located at the top of the first ischolar_main of the neck. Findings: The results show that the stress in the bellows is affected by not only non-symmetrical deformation but also by a combination of the rotation angle and the deflection deformation of the hole as well as the micro hole. The elastic-plastic range around the hole and its relation to the upward lateral deflection and the positive rotation angle was obtained for the bellows in this study. Improvements/Applications: The results are important as they identify the relation between a micro hole and the deformation conditions, and it can be used to improve the quality of bellows.