Regarding expansion joints

Reply to 1# zhenghuacn – it needs to be checked; otherwise, how can you enter the stiffness of the expansion joint? For the stiffness values, please refer to the appendix of GB16749-1997

Sometimes a single calculated expansion joint passes, but it fails when all are calculated.

Reply to 3# zhenghuacn: First of all, you need to understand that the calculation of expansion joints cannot be carried out in isolation, as they have an impact on each other along with the tube sheet. Let’s start by discussing the effect of the data entered for the expansion joint on the tube sheet: if you want to use an expansion joint, you must select it in the tube sheet section; otherwise, the tube sheet will not take into account the data related to the expansion joint. Once the expansion joint is selected, the tube sheet will use the stiffness value you enter there first (when the value you enter differs from the value calculated). If you do not enter a stiffness value for the expansion joint, then the tube sheet calculation will naturally use the stiffness value calculated later. Next is the impact of the tube sheet on the expansion joint: one thing that must be clear is that you cannot calculate the expansion joint in isolation, as the tube sheet has an effect on it. The tube sheet exerts a tensile force on the expansion joint (when the temperature in the tube side is higher than that in the shell side), which increases the axial force on the expansion joint compared to when only internal pressure is present; accordingly, the stress also increases. This is why the calculation works when done separately, but fails when both factors are taken into account. (It took an hour to debug the SW to arrive at these conclusions; these are merely my personal opinions, so please forgive any mistakes.)

I tried it again several times; it seems that one must first calculate the tube sheet, and then calculate the expansion joint； It is incorrect to calculate the expansion joint first and then the tube sheet; I’m curious to know what experts think about this issue

What was said upstairs is correct – they must be calculated together, and there is a sequence to calculating the tube sheets and the expansion joints

Agree with the view from floor 4. . . . . . . . .

Sure, the tube sheet is calculated first; if it fails, a prompt will be given to install expansion joints. At this point, check the expansion joint; if the stiffness or specific parameters of the expansion joint are to be entered. Note that it is or here.

You can check the box, and the software will automatically perform the calculations for you; then you can use GB16749-1997 to select the appropriate model and view its parameters.

I see, there are experts on this forum; now I understand a bit better

I’m also very curious about this question; my rating privileges are limited, so I can only give you one point, haha