in pipe bending, we come across spring back effects, wrinkle effects, effects of

hey .. sorry dude .. no idea ...

agreed with post 1

Well..I have never been good at mathematical kind of formulation...You might want to try asking around on different things,and around where you live,and get different opinions,and which ever the opinion is alike,then try that opinion,and see if it works..And if it does not,then look around again,and then try again.