Lugs in Heads of vertical vessels using line loads-EN 13445/COMPRESS
Lugs in Heads of vertical vessels using line loads-EN 13445/COMPRESS
(OP)
Hello,
I have a question regarding the methodology for using line loads for calculating stresses in lifting lugs in the head of vertical pressure vessels. We recently have compared our methodology to EN-13445-3 (via COMPRESS). We found that the equivalent calculation diameter from EN-13445-3 16.6.3 to be equal to what in my mind should be the effective radius. We have not been able to resolve why this is, and I was wondering if anyone has any knowledge as to why the European code is using the effective diameter as the radius in the calculations?
Thanks
I have a question regarding the methodology for using line loads for calculating stresses in lifting lugs in the head of vertical pressure vessels. We recently have compared our methodology to EN-13445-3 (via COMPRESS). We found that the equivalent calculation diameter from EN-13445-3 16.6.3 to be equal to what in my mind should be the effective radius. We have not been able to resolve why this is, and I was wondering if anyone has any knowledge as to why the European code is using the effective diameter as the radius in the calculations?
Thanks





RE: Lugs in Heads of vertical vessels using line loads-EN 13445/COMPRESS
Some further explanation:
Looking at calcs for lugs on a head, EN-13445 Section 16.6.3 defines equivalent diameter, Deq as follows:
Deq = Ri for spherical sections
and again
Deq = Di×SQRT(1-3((x/Di)^2)) for 2:1 S.E. heads
these numbers seems to be short by a factor of two and I believe should read
Deq = 2×Ri for spherical sections
and
Deq = 2×Di×SQRT(1-3((x/Di)^2)) for 2:1 S.E. heads
I have sketched out the 2:1 head in CAD and checked the calculated Deq against measuring the radius of the arc at varying offset distances, x
(I will try to post my sketches later)
The Deq calcs match the CAD measurement of the radius
The only real concern we have is COMPRESS* uses this Deq calculation for lugs on a head, and my personal calcs have suggested this may result in non-conservative line load stresses in the head
Thanks in advance if anyone can share comments or experience about this
*Build 7110