Hi there,
I've just received a request to carry out stress analysis for newly installed flowlines from "triplex" wellheads which are experiencing serious vibrations problems (the flowlines are falling of their supports and leaking at flange joints). I would appreciate all the help i can get . I intend addressing the problem by increasing the number of restraints. Am I on the right track.

Recent Pipe stress engineer.

It sounds like you may have flow induced vibration which, CAESAR II cannot specifically adress. You can get the natural frequency of the system but your problems origin may very well be due to fluid mechanics.

To AMA_1,
The flow induced vibration cited by John Luf is very likely the result of the wellhead fluid being oil + gas. The two phase flow of liquid and vapor would be complicated by the flow choke that is usually at the wellhead. If a flow choke (orifice) is located in a horizontal run of pipe, then the choke acts as a partial dam for the vapor flow. The vapor might collect into a larger gas bubble until it is pushed through the choke after filling the upper portion of pipe diameter. The frequency of the oil versus gas flow pulses will probably be random.
You have a right approach to add supports. The piping natural frequencies could be obtained by modal analysis. Adding restraints to eliminate the lower frequencies (less than 5 Hz, 10 Hz ?) will reduce motion of piping. Anchors, guides, and axial stops need to be robust substantial structural shapes. Any rod hangers or T-poles will not restrain lateral motion. The guides and stops could include gaps to allow for small thermal growth and not develope excessive thermal stress or loads. The piping with supports could be like a seismically restrained system. If the flow choke is in a horizontal run, then some benefit might be gained by moving it to a vertical run of pipe.