Letter to the Editor commenting on “Letter to the Editor commenting on ‘Maximum Stresses and Flexibility Factors of Smooth Pipe Bends With Tangent Pipe Terminations Under In-Plane Bending’” (Whatham, J. F., 1984, ASME J. Pressure Vessel Technol., 106, pp. 219–220)

Abstract

issue of this journal) [7] on the subject of stress and flexibility factors of smooth pipe bends with tangent pipe terminations under in-plane bending. The aim of this letter is to bring it to notice that the foregoing problem was solved much earlier than the results reported using BENDPAC and to quantitatively give an overall view on the effect of the tangent pipe attachment to the elbow.A finite element program was developed [1] in 1971 (much earlier than BENDPAC), and the end restraint effects on flexibility and stress factors for various pipe factors and bend angles were studied and reported in [2]. Subsequently, this program was used to study elbows with end contraints subjected to out-of-plane moment [3] and internal pressure [4]. This program was modified to include variable thickness of the elbow wall due to manufacturing, and its effect on the flexibility of the elbow was also studied [5].