In a stress package, solution is not converging with default friction stiffness 10^6 lb/in. If I consider a few +Y support as Y, it converges with this friction stiffness. But, this solution requires a few hold-down supports which I don't wish to put. If I reduce friction stiffness to 1/100 times default, the solution converges with +Y supports at the places where I was getting negative operating loads. Which one of these two approximate solution is preferable - compromising with friction or support type ?

regards,

sam

your +ys and problems are telling you that these supports are barely active. What temperature is the system???? If its warm enough the Modulus of Elasticity shift may in actuality cause the piping to bear fully on the supports to a greater extent then what your results indicate!

Sir,

Thanks for your kind reply.

The temperature is 550 F design. You are right. When I run with 1/100 th times default friction stiffness, the pipe lifts up by very small height <0.1 ". With default friction stiffness, these supports take very low upward thrusts. So, as you implied, +Y support will do; no hold-down supports are required.

regards,

sam