as I found from autopipe wiki #46 descripted, autopipe calculating pressure thrust and extension forece based on poisson effect,
as equation, F=P.Ai-v.P.Di/2t x As, where, Ai is inner diameter of pipe, t is wall thickness, As is pipe crossection area,
I calculated 12" STD pipe with 100PSI pressue using AutoPipe simple model and hand calculation,
Autopipe result shown 4523LB force, Hand calculation result shown (pressure thrust 11309 lb- Poisson effece force 6994lb=4315lb ) 4315lb,
there is about 4.8% different, is this a safety factor or not?
another question is that do we need pressure area for expansion joint based on mean diameter area or we only need calculate effect area from outside diameter minus inside diameter (area different)? because pipe inner area pressure thrust force had been calculated already, can the same theory be applied on Victaulic flexible coupling stress analysis,
Thanks
Limin from Fluor
Pressure thrust area
This is the effective cross section area, usually based on the mean diameter of the convolutions of the expansion joint. It is multiplied by the internal pressure to obtain the axial thrust due to internal pressure. This thrust is used if a rigorous pressure extension analysis is requested.