I could not open a support request. Some thing is wrong with the website. However, I did some trial and errors; I found that CAESAR does indeed automatically create a displacement vector based on the API650 calculations. This works only and only if the nozzle element is not connected to a tank model via CNode. So, I will get a displacement vector for the radial displacement and nozzle rotation due to radial thermal expansion and pressure only.

In my case, I have modeled the tank as a piping element that is supported by an anchor at the base and a displacement vector for the settlement (Element 10-20). Then a rigid element without weight from the center of the tank to the tank wall node (Element 20-30). Then a nozzle element at which the nozzle flexibility is defined (Element "31"-40). On the nozzle element the nozzle node is 31 and the tank node (optional) is 30. In this case Caesar does not produce a displacement vector.

My way around that is "not" to choose a displacement vector from the drop down menu, run the error checker and write down the API650 calculated displacement and rotation, conduct a complete run and write down the displacement due to vertical thermal expansion (usually very small for tanks) and settlement, and finally go back to the input and manually set up a displacement vector for both API650, vertical expansion, and settlement. It is obviously very inconvenient, confusing and increases the possibilities of human error.

My question is, is there a better way that will actually make use of Caesar new API650 displacement vector automatic definition feature?