Hi all
I have gone thru some of the topics regarding the modelling of rubber bellows. One thing that i am still confused is that if we select a specific length element to be modelled as rubber bellow, then we need to put all the stiffness values and effective ID in the expansion joint spread sheet. so what about the material . suppose im am modelling piping system of API 5L GrB. Do i need to change the material for rubber bellows to " Custom Material" and input all the values also? If so, How to calculate H1, H2, H3 ... and allowable stresses?

Please help . I would really love to learn more.

thanks