bhushanwd1
Mechanical
- Jun 9, 2013
- 1
Guys,
The equipments is in cyclic pressure service from 0 to 16 Kg/cm^2 g. Nozzle neck, Flange and discontinuity junctions on shell are already verify for fatige life check by FEA as per ASME SEC VII DIV 2 PART 5 & Annexure 3F.
For stud fatigue life evaluation. I had calculate operating bolt load as per ASME SEC VIII guidelines.
Flg size 2" 300#
Operating bolt load = 112815 N
Stud: M16 X 8 Nos
Root area: 138.324 mm^2
Load per bolt: 14102 N
Bolt Stress: 101.3 N/mm^2
Fatigue strength reduction factor: 4
Alternating Stress: (101.3 x 4)/ 2 = 202.6 N/mm^2 (29.4 KSI)
As per Sec VIII DIV 2 PArt 3 Annexure 3F Table 3.F.9 (considering stress < 3 Sa)
X factor comes to 3.74
No of cycles: 10^3.74 = 5487 Nos
Design cycle life = 30000 Nos
Factor = 30000 / 5487 = 5.47
hIGHER THAN UNITY, STUDS ARE FAILING IN FATIGUE LIFE CALCULATIONS.
It is mandetory to evaluate fatigue life check of studs for standard flange as per B16.5?
The equipments is in cyclic pressure service from 0 to 16 Kg/cm^2 g. Nozzle neck, Flange and discontinuity junctions on shell are already verify for fatige life check by FEA as per ASME SEC VII DIV 2 PART 5 & Annexure 3F.
For stud fatigue life evaluation. I had calculate operating bolt load as per ASME SEC VIII guidelines.
Flg size 2" 300#
Operating bolt load = 112815 N
Stud: M16 X 8 Nos
Root area: 138.324 mm^2
Load per bolt: 14102 N
Bolt Stress: 101.3 N/mm^2
Fatigue strength reduction factor: 4
Alternating Stress: (101.3 x 4)/ 2 = 202.6 N/mm^2 (29.4 KSI)
As per Sec VIII DIV 2 PArt 3 Annexure 3F Table 3.F.9 (considering stress < 3 Sa)
X factor comes to 3.74
No of cycles: 10^3.74 = 5487 Nos
Design cycle life = 30000 Nos
Factor = 30000 / 5487 = 5.47
hIGHER THAN UNITY, STUDS ARE FAILING IN FATIGUE LIFE CALCULATIONS.
It is mandetory to evaluate fatigue life check of studs for standard flange as per B16.5?
