The relationship between limit brackets and guide brackets and secondary stress

Assume a straight pipe: if one end is fixed while the other end is free, and no supports are placed along its length to allow it to expand freely, then it is obvious that its thermal stress will be 0. Secondary stress arises as a result of excessive constraints on thermal displacement due to the restriction of deformation, which leads to elevated secondary stress levels

The fundamental purpose of limit brackets and guide brackets is not to handle \"stress\"; stress \"should\" be borne by or offset by fixing brackets. As the name implies, the limiting and guiding brackets are intended solely to direct the expansion of the pipeline in the direction planned by designers. For example, the guide supports near the wave-shaped expansion joint are not intended to bear stress, but rather to guide and protect the expansion joint. Conversely, if the stress on the limiting or guiding bracket is too high, it tends to be damaged and fail to perform its proper limiting or guiding function.

I wonder what the purpose of the original poster in posting this is? I really can’t understand it. Read more about the standards and the definitions of related terms.

This post was last edited by shensi on 2010-11-9 at 14:30. Now I’ll explain exactly what troubles me regarding this issue: I mean that there are specialized supports designed to bear weight, and these are necessary when we install pipelines; gravity also constitutes a type of stress that needs to be taken into account. What I’m thinking about is the adjustment of secondary stresses. However, most materials state that springs should be used when secondary stresses exceed acceptable levels, but they don’t mention the role of guiding and limiting supports. By “role,” I don’t mean the functions of these supports themselves, but rather the reason for their use. As I said at the beginning, guiding and limiting supports are designed specifically for dealing with thermal displacement, that is, for adjusting secondary stresses. Is that correct? Right? Where is the mistake?

Could everyone help me resolve my doubts? Thank you; I’ve thought about this question for a long time and been quite troubled by it.

Secondary stresses in spatial pipelines cause the pipelines and supports to become detached; in such cases, spring supports are used to resolve this issue. There are also many types of guiding and limiting brackets, but they generally cannot withstand excessive stress. Otherwise, fixed support calculations should be performed.

This post was last edited by shensi on 2010-11-10 23:07. Is the setting of the guiding and limiting brackets intended to adjust primary stress or secondary stress? Ensure that the stress meets the standards. Is there indeed an inevitable connection between the guiding and limiting brackets and stress?

Reply 8# shensi: The information below is for reference only. I hope I can help clear up your doubts! Active proposals are welcome! Learn together*! Limiting device: Used in piping systems where it is necessary to restrict displacement in one or more directions. Guiding support (guiding device): Used to direct the direction of pipe displacement or where it is necessary to control the pipe’s rotation around its axis. These devices are used to limit pipe displacement. Under various types of loads, pipes undergo deformation and displacement to varying degrees. Among them, some loads (such as external force loads) have a magnitude that depends on whether deformation is constrained or not; such loads are considered non-self-limiting loads ； Other loads, such as thermal expansion loads, are caused by the restraint of structural deformation; such loads are considered self-limiting loads. For the deformation and displacement of pipes under non-self-limiting loads, it is generally necessary to use support and suspension devices to restrain them, in order to prevent the pipes from being damaged as a result of such loads. To reduce self-limiting loads and prevent pipeline failure due to fatigue, it is required that the pipelines be able to move freely without any constraints. However, it is impossible and unnecessary to require that the pipeline be completely unrestrained. In fact, as long as the secondary stresses generated in pipes under self-limiting loads are kept within a certain range, the safety of the pipes can be ensured. In complex piping systems, the secondary stress levels in different pipe sections vary, and sometimes these differences can be quite significant. At this point, in order to keep the stress levels throughout the entire piping system within safe limits, it is necessary to impose appropriate constraints on pipe displacement, thereby reducing the secondary stresses in those sections where the stress levels exceed the allowable limits. In summary, it is not only possible but also necessary to install limit devices at appropriate locations in the piping system. The key is to correctly select the location for installing the limiting device and the type of limiting device to use (mainly the restraint model).