sample cal

DESIGN CALCULATION

DESIGN CALCULATION

PLATE HEAT EXCHANGER

(Fully Welded Hybrid Heat Exchanger Cryogenic Application)

FEED GAS/ RESIDUE GAS EXCHANGER

ITEM No: 3E-251 (New)

Location: BUHASA, Abu Dhabi

Rev: Date: Prepared: Issued for Approval

1 01.10.2013 Frank Betzold

Calculation

Finite Element Analysis

Report

Finite Element Analysis

of the

Hybrid Heat Exchanger Gasco02

Version 1.0

powered by

NX NASTRAN + FEMAP

SMART Engineering GmbH

Dipl.-Ing. Marco Solterbeck

Herrenheide 15a

D-21244 Buchholz

Phone: +49 4181/215900

Fax: +49 4181/215909

eMail: [email protected]

Internet: www.smart-fem.de

10-01-2013


2

Content

1. Project Definition ................................................................ 3

2. Regulations und design fundamentals ................................. 3

3. FE-Model ............................................................................. 3

4. Material Properties .............................................................. 5

5. Boundary Conditions ........................................................... 6

6. Verification of static strength due to test pressure ............. 7

6.1. Loadings ............................................................................... 7

6.2. Allowable stresses according to AD 2000 S4 .............................. 8

6.3. Analysis Results ..................................................................... 9

6.4. Verification according to AD 2000 S4 .......................................19

7. Verification of static strength due to operating pressure .. 19

7.1. Loadings ..............................................................................19

7.2. Allowable stresses according to AD 2000 S4 .............................21

7.3. Analysis Results ....................................................................22


8. Verification of the side lugs ............................................... 32

8.1. Loadings ..............................................................................32

8.2. Allowable stresses according to AD 2000 S4 .............................33 8.3. Analysis Results ....................................................................33


8.5. Reaction forces side lugs ........................................................36


3

1. Project Definition

For the housing of a hybrid heat exchanger the proof of the deformations and stresses based

on the finite element method shall be performed. Thereby has to be verified the strength of

the assembly due to test pressure and operating pressure.

For the side lugs the following load components are to be considered in different combina-

tions: dead weight of the structure, positive and negative nozzle loads, wind loads and earth-

quake loads.

The proofs will be carried out according to the rule type AD 2000 Guideline.

2. Regulations und design fundamentals

Used FEA-Software:

- Solver: NX Nastran, Release 8.5.1

- Pre-/Postprocessor: Femap, Release 11.0.1

Considered regulations and documents:

/ 1 / 2D-Drawing WH0887_sketch6.pdf 08-29-2013

/ 2 / 3D-Geometry data in Step-Format Gasco02_Bild_Step.stp

/ 3 / AD 2000 Guideline

/ 4 / Material data provided by SPX Flow Technology Rosista GmbH

/ 5 / Technical data provided by SPX Flow Technology Rosista GmbH

Table 1: Considered regulations and documents

3. FE-Model

The analysis model was created based on 3D-Geometry data in Step-Format. The discretiza-

tion of the model has been done almost exclusively with linear plate elements under consider-

ation of their corresponding wall thicknesses. The connections of the parts have been assumed

as ideal node couplings (merged coincident nodes). Welds and bolted connections have not been represented in detail. The modeling of the horizontal and vertical tie rods has been done

by beam elements with the corresponding cross sections. These beams have been connected

to the structure with rigid elements. The first inner rows of the vertical tie rods were meshed

in detail with brick elements.

Attached parts which are not relevant for stiffness were neglected. The same applies also for

the inner plate package, due to the soft connection to the structure. To keep the equilibrium

under pressure loads all nozzles have been closed.

Figure 1 to Figure 3 show the analysis model which has following characteristics:

Number of elements 433,585

Number of nodes 465,773

Table 2: Characteristics of the FE-Model


4

Figure 1: FE-Model, exterior view

Figure 2: FE-Model, sectional view


5

Figure 3: FE-Model, detailed view, tie rod connection at first inner row

4. Material Properties

The used material was assumed to be linear-elastic according to Hookes law. As the stresses

and strains to be verified are associated with different temperature conditions, the considera-

tion of appropriate material properties was required. As base for all further examination the

following properties / 4 / have been considered:

Material

Temp. Youngs

Modulus

Poisson's

Ratio

Yield Strength

Rp0,2

Tensile Strength

Rm

[C] [N/mm2] [-] [N/mm] [N/mm2]

1.4404

20 200,000 0.29 260 530

85 195,125 0.29 210 -

1.4571

20 200,000 0.29 260 540

85 195,125 0.29 225 -

Table 3: Material Properties

The adjustment of the properties to AD 2000 is done in section 6.2, 7.2 and 8.2.

Welding seam

(brick elements)

Tie rod

(beam elements)

Tie rod

(brick elements)

End plate

(brick elements)


6

Figure 4: FE-Model, sectional view, used materials with different colors

5. Boundary Conditions

The housing was constrained with static definitions at the two lugs under consideration of

contact with the grounding plate. Additionally both bolts at each lug were fixed in all direc-

tions. The constraints of the model are shown in Figure 5.

1.4571 (green)

1.4404 (red)


7

Figure 5: FE-Model, supports (constraints)

6. Verification of static strength due to test pressure

6.1. Loadings

For the verification of static strength in the test case a test pressure of 41.5 bar was applied

to the entire housing. Figure 6 shows the pressure distribution in the FE-Model.

Contact considered

between lug and grounding plate (grey)

Grounding plate and bolts fixed in all directions


8

Figure 6: FE-Model, pressure distribution under test conditions

6.2. Allowable stresses according to AD 2000 S4

The determinations of the allowable stresses according to AD 2000 S4 are based on the

material properties from Table 3. The allowable stresses have been calculated based on the

following equations and are listed in Table 4:

f20C = K20C / S with K20C = Rp1,0, safety factor S = 1.05 and welding factor v

Primary global membrane stress:

Pm20C = 1.0 f20C v

Primary local membrane stress:

Pl20C = 1.5 f20C v

Primary membrane + bending stress:

Pm20C + Pb20C = Pm20C + Pl20C = 1.5 f20C v

Primary membrane + bending Stress + secondary stress

Pm20C + Pb20C + Q20C = Pm20C + Pl20C + Q20C = 3 f20C v

Material f20C Welding

factor

Pm20C

[N/mm2]

Pl20C

[N/mm2]

Pm+Pb(l)

[N/mm2]

Pm+Pb(l)+Q

[N/mm2]

1.4404 247 1,00 247 370 370 741

1.4571 247 1,00 247 370 370 741

0,85 210 315 315 630

Table 4: Allowable stresses according to AD 2000 S4, test situation

Test pressure 41.5 bar = 4.15 N/mm

Test temperature T = 20 C


9

6.3. Analysis Results

For result evaluation the established membrane stresses and von Mises equivalent stresses

have been used.

In Figure 7 to Figure 25 the stresses are given on the deformed structure. For clarification the

deflections are scaled by a factor of 50.

The stress legend of the first figures is limited to the maximum relevant stress value of the

shown model part. In further figures the legend was scaled to the allowable AD 2000 S4

values.

Figure 7: FE-Model, full model, top view, Equivalent Stress [N/mm]


10

Figure 8: FE-Model, full model, bottom view, Equivalent Stress [N/mm]

Figure 9: FE-Model, top cover, Equivalent Stress [N/mm]

780 N/mm (surface tension)

1.210 N/mm (max. local stress peak)


11

Figure 10: FE-Model, bottom cover, Equivalent Stress [N/mm]

Figure 11: FE-Model, vertical tie rods, Equivalent Stress [N/mm]

290 N/mm


12

Figure 12: FE-Model, horizontal tie rods, Equivalent Stress [N/mm]


Legend scaled to allowable

stress according AD2000 S4

S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f

193 N/mm


13


Figure 15: FE-Model, welding seams (welding factor 0.85), Equivalent Stress [N/mm]

Legend scaled to allowable stress according AD2000 S4

S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f

Legend scaled to allowable stress

according AD2000 S4

blue: Pm = 1,0 f 0.85

yellow: Pm+P

b = 1,5 f 0.85

orange: Pm+P

b +Q = 3,0 f 0.85

red: > Pm+P

b +Q = 3,0 f 0.85

Welding seam

Welding seam


14

Figure 16: FE-Model, middle end plate, Equivalent Stress [N/mm]




S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f

Material 1.4404


S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f


15


Figure 19: FE-Model, full model, top view, Membrane Stress [N/mm]



S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f

Grey areas, no values available


S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f


16

Figure 20: FE-Model, full model, bottom view, Membrane Stress [N/mm]

Figure 21: FE-Model, welding seams (welding factor 0.85), Membrane Stress [N/mm]


S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f




blue: Pm = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f

Welding seam

Welding seam


according AD2000 S4

blue: Pm = 1,0 f 0.85

yellow: Pm+P

b = 1,5 f 0.85

orange: Pm+P

b +Q = 3,0 f 0.85

red: > Pm+P

b +Q = 3,0 f 0.85

Welding seam

Welding seam


17

Figure 22: FE-Model, middle end plate, Membrane Stress [N/mm]

Figure 23: FE-Model, top cover, Membrane Stress [N/mm]



S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f

589 N/mm (max. local stress peak)


S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f

Material 1.4404


18

Figure 24: FE-Model, bottom cover, Membrane Stress [N/mm]

Figure 25: FE-Model, displacements [mm]



S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f


19

6.4. Verification according to AD 2000 S4


have been used.

The proof of fatigue according to AD 2000 S4 is regarded as given under 6.3 when the calcu-

lated stresses are lower than the allowable stresses determined in 6.2.

The primary local membrane stresses are below the allowable value of 370 N/mm. Only at

the corners of the end plates the stresses locally exceeds this value.

Pl20C = 589 N/mm > 370 N/mm (Figure 23, upper end plate)

The Primary local membrane + bending stresses + secondary stresses are below the allowable

value of 370 N/mm. Only at the corners of the end plates and the welding seams of the tie

rods the stresses locally exceeds this value.

Pl20C + Pb20C + Q20C = 1.210 N/mm > 741 N/mm (Figure 9, upper end plate)

Pl20C + Pb20C + Q20C = 780 N/mm > 741 N/mm (Figure 9, welding seam tie rod)

Within the scope of the assumptions the strength proof of all components is regarded with the

exception of the end plate and the welding seams of the tie rods.

The stresses in these areas require a separate interpretation. The local stress distribution

allows the conclusion, that in these areas the material will yield causing a slight local plastic

deformation and thus the peak stresses will be reduced. Assuming that the pressure test is a

single event a failure of the structure is not to be expected

In the areas of the welding seams with the reduced welding factor of 0.85 the membrane and

equivalent stresses are below the allowable values (Figure 21 and Figure 15).

7. Verification of static strength due to operating pressure

7.1. Loadings

For the verification of static strength in the operating case an allowable pressure of 29.0 bar

was applied to the entire housing. Furthermore the nozzle loads in positive (Figure 27) and

negative (Figure 28) directions have been considered. Figure 26 shows the pressure distribu-

tion in the FE-Model.


20

Figure 26: FE-Model, pressure distribution under operating conditions

Figure 27: FE-Model, positive nozzle loads (nozzle 1 to 4)

Operating pressure 29.0 bar = 2.9 N/mm

Operating temperature T = 85 C

Forces [N] Moments [Nmm]

N1 N1

N4

N2 N2

N3 N3 N4

Resulting positive nozzle forces: Fx = -57.0 kN; Fy = 66.0 kN; Fz = 58.5 kN


21

Figure 28: FE-Model, negative nozzle loads (nozzle 1 to 4)







Pm85C = 1.0 f85C v


Pl85C = 1.5 f85C v






factor

Pm85C

[N/mm2]

Pl85C

[N/mm2]

Pm+Pb(l)

[N/mm2]

Pm+Pb(l)+Q

[N/mm2]

1.4404 140 1,00 140 210 210 420

1.4571 150 1,00 150 225 225 450

0,85 127 191 191 382

Table 5: Allowable stresses according to AD 2000 S4, operating situation

N1 N1

N4

N2 N2

N3 N3 N4

Forces [N] Moments [Nmm]

Resulting negative nozzle forces: Fx = 57.0 kN; Fy = -66.0 kN; Fz = -58.5 kN


22



have been used. Relevant for the stress evaluation is the load case with negative nozzle loads.

At this load case the maximum stress appears in the structure.

In Figure 29 to Figure 46 the stresses are given on the deformed structure. For clarification

the deflections are scaled by a factor of 50.

The stress legend of the first figures is limited to the maximum relevant stress value of the

shown model part. In further figures the legend was scaled to the allowable AD 2000 S4

values.



23



549 N/mm (surface tension)



24


Figure 33: FE-Model, vertical tie rods, Equivalent Stress [N/mm]

204 N/mm


25

Figure 34: FE-Model, horizontal tie rods, Equivalent Stress [N/mm]




S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f

136 N/mm


26


Figure 37: FE-Model, welding seams (welding factor 0.85), Equivalent Stress [N/mm]


S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f


according AD2000 S4

blue: Pm = 1,0 f 0.85

yellow: Pm+P

b = 1,5 f 0.85

orange: Pm+P

b +Q = 3,0 f 0.85

red: > Pm+P

b +Q = 3,0 f 0.85

Welding seam

Welding seam


27

Figure 38: FE-Model, middle end plate, Equivalent Stress [N/mm]




S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f

Material 1.4404


S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f


28

Figure 40: FE-Model, full model, top view, Membrane Stress [N/mm]

Figure 41: FE-Model, full model, bottom view, Membrane Stress [N/mm]



S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f


S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f




29

Figure 42: FE-Model, welding seams (welding factor 0.85), Membrane Stress [N/mm]

Figure 43: FE-Model, middle end plate, Membrane Stress [N/mm]


blue: Pm = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f

Welding seam

Welding seam


blue: Pm = 1,0 f 0.85

yellow: Pm+P

b = 1,5 f 0.85

orange: Pm+P

b +Q = 3,0 f 0.85

red: > Pm+P

b +Q = 3,0 f 0.85

Welding seam

Welding seam


S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f

Material 1.4404


30

Figure 44: FE-Model, top cover, Membrane Stress [N/mm]

Figure 45: FE-Model, bottom cover, Membrane Stress [N/mm]



S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f




S4 blue: P

m = 1,0 f

yellow: Pm+P

b = 1,5 f

orange: Pm+P

b +Q = 3,0 f

red: > Pm+P

b +Q = 3,0 f


31

Figure 46: FE-Model, displacements [mm]



have been used.



The primary local membrane stresses are below the allowable value of 370 N/mm. Only at

the corners of the end plates the stresses locally exceeds this value.

Pl20C = 418 N/mm > 225 N/mm (Figure 44, upper end plate)


value of 370 N/mm. Only at the corners of the end plates and at the welding seams of the tie

rods the stresses locally exceeds this value.

Pl20C + Pb20C + Q20C = 859 N/mm > 450 N/mm (Figure 31, upper end plate)

Pl20C + Pb20C + Q20C = 549 N/mm > 450 N/mm (Figure 31, welding seam tie rod)

Within the scope of the assumptions the strength proof of all components is regarded with the exception of the end plate and the welding seams of the tie rods.

The stresses in these areas require a separate interpretation. The local stress distribution

allows the conclusion, that in these areas the material will yield causing a slight local plastic

deformation and thus the peak stresses will be reduced. Assuming that the pressure test is a

single event a failure of the structure is not to be expected

In the areas of the welding seams with the reduced welding factor of 0.85 the membrane and

equivalent stresses are below the allowable values (Figure 42 and Figure 37).


32

8. Verification of the side lugs

8.1. Loadings

For the verification of the side lugs the load cases listed in Table 6 have been considered. The

pressure was neglected.

Load case 3a 3b 4 5a 5b

Self-weight, operation, full mop,full = 40.268 t / 5 / x x - x x

Self-weight, testing, full mtest,full= 67.740 t / 5 / - - x - -

Nozzle loads, positive direction (Figure 27) / 1 / x - - x -

Nozzle loads, negative direction (Figure 28) / 1 / - x - - x

Wind load, full (Figure 47) / 5 / x x - - -

Wind load, half / 5 / - - x - -

Earthquake loads (Figure 47) / 5 / - - - x x

Table 6: Load cases for verification of the lugs

The wind and earthquake loads were applied to the center of gravity of the heat exchanger.

The connection between the load point and the meshed structure was done with a non-

stiffening interpolation element.

Figure 47: FE-Model, wind and earthquake loads

Wind loads [N]

Center of gravity

Earthquake loads [N]

Center of gravity


33







Pm85C = 1.0 f85C v


Pl85C = 1.5 f85C v






factor

Pm85C

[N/mm2]

Pl85C

[N/mm2]

Pm+Pb(l)

[N/mm2]

Pm+Pb(l)+Q

[N/mm2]

1.4571 150 1,00 150 225 225 450

Table 7: Allowable stresses according to AD 2000 S4, operating situation



have been used. The maximum stresses and deformations of the considered load cases are

listed in Table 8.

Load case Membrane Stress

[N/mm]

Equivalent Stress

[N/mm]

Displacement

[mm]

3a 36 49 1.03

3b 42 58 1.15

4 33 45 0.59

5a 39 85 1.05

5b 62 87 1.50

Table 8: Stresses and displacements of the lugs

In Figure 48 to Figure 50 only the stresses of the load case with the maximum stress value

are given on the deformed structure. For clarification the deflections are scaled by a factor of

50.

The stress legend of the following figures is limited to the maximum relevant stress value of

the shown model part.


34

Figure 48: FE-Model, side lug, Equivalent Stress [N/mm]

Figure 49: FE-Model, side lug, Membrane Stress [N/mm]

87 N/mm

62 N/mm


35

Figure 50: FE-Model, side lug, displacements [mm]



have been used.



The primary local membrane stresses are below the allowable value of 225 N/mm.

Pl20C = 62 N/mm < 225 N/mm (Figure 49)


value of 225 N/mm.

Pl20C + Pb20C + Q20C = 87 N/mm < 450 N/mm (Figure 48)

Within the scope of the assumptions the strength proof of the side lugs is regarded.


36

8.5. Reaction forces side lugs

The calculated values for the reaction forces of the both side lugs named in Figure 51 are

listed in Table 9.

Figure 51: FE-Model, side lug positions for reaction loads

Load case

Side lug A Side lug B

FRx [kN]

FRy [kN]

FRz [kN]

FRx [kN]

FRy [kN]

FRz [kN]

3a 64,0 250,6 -51,3 -30,3 78,5 -19,8

3b 29,5 135,4 38,3 -109,8 325,6 7,5

4 90,5 332,4 -3,3 -102,2 332,1 -3,1

5a 13,9 212,3 -78,8 -80,4 116,8 -46,9

5b -21,8 98,1 11,1 -158,7 362,9 -19,7

Table 9: Reaction forces side lugs

Side lug A Side lug B

sample cal

Documents

analysis results

allowable stresses

test pressure

operating pressure

rule type ad

finite element method

project definition

negative nozzle loads