Caesar II stress analysis and modeling

I value of small tubules/I value of large tubules

During pipeline stress analysis, the main pipes require stress analysis, while some branch pipes (drainage and vent pipes) do not need it. So, how should these pipelines that do not require stress analysis be handled during modeling? But if this part is not modeled, it seems that the interaction between the weight of this part and the pipeline connections is overlooked. If all of these pipelines are modeled, it seems not quite appropriate if the maximum stress is found in these pipelines during analysis. Please share your thoughts on the most appropriate way to handle this, thank you. I think it’s not necessary to model these pipelines, such as those for drainage and venting. For pipeline systems, the biggest impact of drainage and venting pipelines is their own weight; however, this impact is relatively small for SUS main pipelines, and since they are free-end pipes, I personally believe there’s no need to model them.

I agree with what was said above; the main factors considered in pipeline stress analysis are not the weight of the pipelines themselves. Stress-induced failure is primarily caused by thermal stresses, vibrations, etc., and small branches can be ignored. If the mass of the branch pipe is significant, such as in the case of long vent pipes – we have carried out projects at steel mills where these vent pipes need to be more than 10 meters above the ground level – then their mass cannot be ignored. A node can be added at the branching point, and its weight can be estimated to be used as an additional external force in the calculations.

I’ve learned something from this; I think it’s also necessary to consider the effect of the branch pipe’s weight on the main pipe, and at that point the stress on the branch pipe should not be the focus of the analysis. Another advantage of branch pipe modeling is that it allows one to determine the stress conditions on these branches, providing a basis for deciding what type of supports to use.

During pipeline stress analysis, the main pipes require stress analysis, while some branch pipes (drainage and vent pipes) do not need it. So, how should these pipelines that do not require stress analysis be handled during modeling? But if this part is not modeled, it seems that the interaction between the weight of this part and the pipeline connections is overlooked. If all of these pipelines are modeled, it seems not quite appropriate if the maximum stress is found in these pipelines during analysis. Please share your thoughts on the most appropriate way to handle this, thank you. It mainly depends on the extent to which the weight of the branch pipe affects the main pipe; if the impact is minor, there’s no need to worry about it. In fact, the factors affecting weight are secondary; priority should be given to the displacement at the connection points, for example ； If the displacement is large and the stress at the connection points exceeds the allowable limits, it is necessary to adjust the direction of the pipeline or change the location of the connection between the branch pipe and the main pipe.

I agree with what the people above have said. In such cases, it’s necessary to analyze each specific situation individually. The drainage and vent pipes mentioned by the original poster are relatively small in size and have free ends; therefore, their impact on the main pipe is extremely limited, so they can be ignored. However, it is still necessary to simulate some high-temperature piping systems, as well as those closed drainage or venting pipelines that are connected to the main pipes. This is mainly to check whether the stresses resulting from temperature differences exceed the allowable values.

I would like to ask how to proceed with what was mentioned on floor 4: \"A node can be added at the branch point, and an estimated weight can be used as an external additional force for calculation.\" Not familiar with CII! Thank you!