Dear All
A conical section with half apex angle of 15 degrees is going to be joined to a cylinder of different thickness. The difference in thickness is 20 mm. Is there any requirements for a tapered transition as per UW-9 or UW-13 for this joint? In tapered transition requirement is there any...
TGS4
That would be so nice of you. I sent you an E-mail through my G-mail contact. I am also a member in RDG of BPV VIII. However, I do not know if it is possible to make contact through C&S Connect tools. If it were possible it would have been great.
Anyways thank you so much for helping...
Thank you again for these helpful comments.
Still I cannot understand what is the difference between design margins in EP analysis for plastic collapse protection and buckling protection when they both use the procedure in 5.2.4 and use the load factors as presented in table 5.5. the beta...
Thank you TGS4 for your explanations.
I must say that it would be better to think about incorporating E < 1.0 in DBA since it is not always a matter of special design or care regarding sensitive equipment that encourages DBA. Sometimes, other reasons like the geometries outside the scope of...
Thank you IdanPV and TGS4 for helping me.
1- Does this mean that the true strain for true yield stress is equal to ep (ep epsilonp)? I am asking since in 2021 edition the code has been modified to consider true strain to be linearly proportional to true stress when Gamma1+Gamma2 is less than ep...
Dear All
I am running an elastic-plastic analysis of an equipment as per ASME BPVC VIII-2 Ed. 2021. I have some questions hope you could help me.
1- I am using Ansys workbench. As I understand in material properties for FEA true plastic strain vs true stress shall be the input data. Based on...
Jtseng
This has been added to the code since edition 2013. The restriction is only on the reduction in weld thickness not the plate and therefore one remedy could be using crown and petal by forming head pieces first and then welding the pieces together so that the weld does not strain.
I want...
R6155
The adjoining thicknesses are 35 mm and 10 percent of 35 is 3.5. therefore, for this special case the reduction in weld thickness due to forming shall not exceed min( 1 mm, 3.5 mm) which means 1 mm. In fact if the thickness of plates to be formed after welding is more than 10 mm then the...
R6155
The paragraph clearly states the reduction in weld thickness which means 35-31=4 mm.
Which is not good since it is more than 1 mm limit on the weld thickness reduction by forming.
OK David
Well to my eyes the requirement sounds like a limit on the weld strain not the plate strain. I have seen some engineering specifications recommend that if the heads cannot be fabricated from a single plate it is better to fabricate them in the crown and petal pattern and first form the...
David
The wording of the code does not allow a reduction in weld thickness above 1 mm. It says it is acceptable if this limit is not exceeded. How do you say this is not an issue? It violates this paragraph of the code.
David the problem is that what happens if the thinning exceeds the limit of 1 mm (or 10 percent of the plate thickness)?
It is not about thickness being reduced to required thickness by design. It is a question of reduction in the thickness with respect to initial before forming thickness...
r6155 Thank you for reminding me to read UG-79 in full which is my question in the first place.
It was not clear to my eyes and that is why I have asked this question. It is silent on how to deal with the component if the reduction in the weld thickness exceeds the limit. Does the component have...
Dear all
Please help me understand this issue regarding forming of heads fabricated from more than one piece.
ASME BPVC VIII-1 UG-79, regarding weld thickness reduction due to forming, reads:
Does this mean that for head fabrication, if the head is fabricated by forming a blank which has a...
I am not concerned with peak stresses. Actually I do not understand how peak stresses can be extracted from shell element. I thought the stresses at the middle layer are membrane and at the top or bottom are membrane plus bending and no indication of peak stresses in shell elements...
When I have solid elements I can handle sharp edges with some fillets with some radius. But I do not know how to remove this issue when I have shell elements where the stresses will not stop increasing by reducing mesh size.
Dear all
I am reviewing an elastic stress analysis of legs to shell junction for protection against plastic collapse. The vendor wants to show that the stress results for the analysis are free from mesh size. First he has reduced the mesh size from 100 mm to 50 mm and the maximum stress has...
Dear all
How would you categorize stresses in an elbow due to internal pressure?
Is it ok if I take membrane stresses as primary and bending stresses as secondary?
I am talking about a ninety degree elbow with stresses considered at the 45 degrees section. The elbow is attached at both sides...
TGS4, in the assessment procedure for elastic-plastic method it is mentioned in 5.2.4.4 that a material model that includes hardening or softening, or an elastic perfectly plastic model may be utilized. My question is that in the case of elastic perfectly plastic model what should be the yield...
