shiraz883
Automotive
- Nov 15, 2006
- 48
Hi,
I am doing a Finite element evaluation of a perforated tubesheet (U-tube exchanger -thick tubesheet currently) for a superheater and want to optimize it.
I am making use of Annex 5-E of ASME div 2 part 5 of modeling an equivalent solid plate. Since the loading is not axis symmetric so I cannot go for a 2D axis-symmetric model. To avoid the perforation and hence meshing difficulties (I have tried meshing for a part of the thick TS) I would like to make a solid TS representing perforated TS with solid TS having equivalent E* and v* from Annex 5-E.
From annex 5-E.2.2, for triangular penetration patterns the in-plane behavior of the tubesheet is isotropic and the anisotropy of the equivalent material must only be considered for stresses in the thickness
direction which means that 'E' will be a lower value (from table 5-E.1) but will be isotropic (Ex=Ey=Ez) but stresses when computed in thickness direction (through thickness) will have to increased to account for the holes?
Also v (Poisson's ratio) will be different (as per table 5-E.2)
My question is "Is it possible to do a 3D evaluation whereby modeling a solid plate representing the perforated plate? or is it only applicble when we are doing and axis symmetric evaluation?
Also I am in doubt about table 5-E.1 and Table 5-E.8 for E calculation of solid plate?? Also about Poisson ratio values?
Shiraz
Sr. Engineer
I am doing a Finite element evaluation of a perforated tubesheet (U-tube exchanger -thick tubesheet currently) for a superheater and want to optimize it.
I am making use of Annex 5-E of ASME div 2 part 5 of modeling an equivalent solid plate. Since the loading is not axis symmetric so I cannot go for a 2D axis-symmetric model. To avoid the perforation and hence meshing difficulties (I have tried meshing for a part of the thick TS) I would like to make a solid TS representing perforated TS with solid TS having equivalent E* and v* from Annex 5-E.
From annex 5-E.2.2, for triangular penetration patterns the in-plane behavior of the tubesheet is isotropic and the anisotropy of the equivalent material must only be considered for stresses in the thickness
direction which means that 'E' will be a lower value (from table 5-E.1) but will be isotropic (Ex=Ey=Ez) but stresses when computed in thickness direction (through thickness) will have to increased to account for the holes?
Also v (Poisson's ratio) will be different (as per table 5-E.2)
My question is "Is it possible to do a 3D evaluation whereby modeling a solid plate representing the perforated plate? or is it only applicble when we are doing and axis symmetric evaluation?
Also I am in doubt about table 5-E.1 and Table 5-E.8 for E calculation of solid plate?? Also about Poisson ratio values?
Shiraz
Sr. Engineer