Why doesn’t the code check the moment caused by friction at the bottom of the saddle?
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This post was last edited by FMSD on 2018-5-10 at 12:29. Why doesn’t the standard take into account the bending moment caused by the friction at the bottom of the saddle?
The content of the screenshots you showed relates to the checking of gussets and web members; what I mean is that the effect of this bending moment on the cylinder should also be taken into account； Of course, this bending moment in the horizontally placed horizontal container does not need to be combined with M2, as it is caused by temperature and represents a secondary stress ； For a pipe like the one in the figure below, this bending moment is not caused by temperature; therefore, it needs to be considered in combination with M2. Of course, this one doesn’t belong to the container; I’ve already added this bending moment to M2.
This post was last edited by wanlirn on 2018-5-12 at 16:15. It doesn’t seem to be the case; for your type of structure, it should be calculated based on pipe supports, or as a precaution, based on bracket supports
This post was last edited by FMSD on 2018-5-14 at 13:22. Mine is a cross-sectional view, not an ear-type support; it’s actually like this. I’ve reviewed the domestic standards for pipe supports and hangers, and they basically don’t take local stresses into account. Only the bearing capacity of the support itself was considered.
This post was last edited by zjq1962 on 2018-5-14 at 16:35. NB/T47042 does not take into account the effect of horizontal seismic forces on the cylinder of horizontal containers; it only considers the verification of the compressive stress on the saddle and the stress on the foundation bolts under horizontal seismic forces. Not to mention the effect of the friction between the saddle bottom plate and the foundation on the cylinder.
Does that mean there are still some vulnerabilities?
That’s how I understand it: horizontal vessels are not as tall as tower-type equipment, so horizontal seismic forces have little impact on the stresses in the vessel shell; it is sufficient to ensure the strength of the saddle itself as well as the stress levels of the bolts.
I am very interested in the calculation of local stresses in non-standard shell structures, but this area is highly variable, and there are no authoritative calculation methods available in China. Finite element analysis is somewhat slow, and there are also few books available on using finite element methods for calculating local stresses in shell structures
It seems the original poster likes to analyze design.