FEA
PIPE TO PIPE CONNECTION
WITH HEADER FULL ENCIRCLEMENT
E(v-M)S as the friction coefficient between header and
HFE varies
SCOPE OF WORK
The scope of the work in this document is to perform a FEA on a pipe to pipe connection to understand how the
E(v-M)S varies as the coefficient of friction between the HFE(*) and the header varies.
Five FEA will be performed with the following friction coefficients:
FEA No.
1
2
3
4
5
FRICTION COEFFICIENT
μ1
0.3
[-]
μ2
0.4
[-]
μ3
0.5
[-]
μ4
0.6
[-]
μ5
0.7
[-]
In the following slides all the calculation details will be illustrated.
(*) HFE: HEADER FULL ENCIRCLEMENT
3D MODEL AND INPUT DATA
ISOMETRIC VIEW
BRANCH
CIRCUMFERENTIAL
WELD 3
CIRCUMFERENTIAL
WELD 2
CIRCUMFERENTIAL
WELD 1
HEADER
LONGITUDINAL VIEW
HEADER FULL
ENCIRCLEMENT
NOTE: In the 3D model, the longitudinal weld that joins the two shells of the header full
encirclement was neglected because it was assumed that it would not touch the run pipe.
INPUT DATA
OD
ID
THKFEA
E
HEADER
100
98
1
200000
[mm]
[mm]
[mm]
[MPa]
OD
ID
THKFEA
E
BRANCH
50
48
1
200000
[mm]
[mm]
[mm]
[MPa]
HEADER FULL ENCIRCLEMENT
OD
102
[mm]
ID
100
[mm]
THKFEA
1
[mm]
E
200000
[MPa]
PRESSURE AND TEMPERTURE
P
2
[MPa]
H PC
49
[MPa]
B PC
24
[MPa]
T
21
[°C]
B PC
FIXED
SUPPORT
H PC
P
CONTACTS
FRICTIONAL CONTACT
BONDED CONTACT
BRANCH
WELD 2
HEADER
WELD 1
WELD 3
- THE CONTACTS BETWEEN THE WELDS AND
THE PIPES HAVE BEEN CONSIDERED BONDED
- THE CONTACT BETWEEN THE HEADER,
BRANCH AND HEADER FULL ENCIRCLEMENT
HAS BEEN CONSIDERED FRICTIONAL
HEADER FULL
ENCIRCLEMENT
FEA No.1 - RESULTS – E(v-M)S – FRICTION COEFFICIENT μ1=0.3
MAX E(v-M)S = 321.89 [MPa]
FEA No.2 - RESULTS – E(v-M)S – FRICTION COEFFICIENT μ2=0.4
MAX E(v-M)S = 315.54 [MPa]
FEA No.3 - RESULTS – E(v-M)S – FRICTION COEFFICIENT μ3=0.5
MAX E(v-M)S = 308.63 [MPa]
FEA No.4 - RESULTS – E(v-M)S – FRICTION COEFFICIENT μ4=0.6
MAX E(v-M)S = 306.81 [MPa]
FEA No.5 - RESULTS – E(v-M)S – FRICTION COEFFICIENT μ5=0.7
MAX E(v-M)S = 307.4 [MPa]
FEA No.6 - RESULTS – BONDED CONTACT BETWEEN HFE AND RUN PIPE
A further FEA was performed to highlight the differences between bonded and frictional contacts.
In the FEA No.6 of which I highlight the details below, the contact between the header full encirclement and the run pipe is considered
bonded.
The boundary conditions were kept identical to previous analyses, please see slide No.4 for reference.
THE HEADER RED SURFACE AND THE
HFE BLUE SURFACE ARE JOINED BY A
BONDED CONTACT
MAX E(v-M)S = 307.64 [MPa]
RESULTS – CONCLUSIONS
The table below shows the Equivalent von-Mises Stress and Local Primary Membrane Equivalent Stress (PL) as a function of the
friction coefficient.
The columns in red highlight the percentages of each FEA with respect to the E(v-M)S and Local Primary Membrane Equivalent
Stress (PL) with a friction coefficient equal to 0.3. As can be seen, the E(v-M)S and PL values ​decrease as the friction coefficient
increases with the exception of FEA No.5 E(v-M)S where, however, the difference compared to FEA No.4 is 0.59 Mpa.
μ-E(v-M)S
324
322
FEA No.
1
2
3
4
5
6
321.89
320
E(v-M)S
[MPa]
318
316
315.54
314
μn
[-]
0.3
0.4
0.5
0.6
0.7
-
E(v-M)S
[MPa]
321.89
315.54
308.63
306.81
307.4
307.64
%
E(v-M)S
2.01
4.30
4.92
4.71
4.63
PL - H
[MPa]
216.88
216.25
214.98
213.21
212.34
184.25
%
PL - H
0.29
0.88
1.72
2.14
17.71
312
310
308.63
306.81
308
306
307.4
0.2
0.3
0.4
0.5
FRICTION COEFFICIENT
[-]
0.6
0.7
0.8
In the highest stress zone, the difference
between the Local Primary Membrane
Equivalent Stress of FEA No.5 and FEA No.6
is 28.09 MPa
NOTE: The Local Primary Membrane Equivalent Stress (PL) was taken in the most stressed area of ​the header