__ANSYSPrac-9c.pdf

7/29/2019 __ANSYSPrac-9c.pdf

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ANSYS Practice No. 9C

Thermal-Stress Analysis using the Direct Coupled Method

Pipe with Cooling Fins

Description:

To analyse the thermal-stress filed in the Stainless steel pipe with cooling fins using the

Direct Coupled Method. The thermal loadings are the same as in Practice 9A, with the internal

pressure of 1000 psi applied to the model simultaneously. The material property of 304

Stainless Steel is as follows:

Youngs Modulus:2.7993e7 (lbf/in2) Poissons ratio: 0.29

Specific heat: 46.286 (Btu/lb) Conductivity: 0.21822e-3 (Btu/(hr-in-oF)

Density: 0.75148e-3 (lbf-sec2/in4) Thermal expansion coefficient: 0.9889e-7 (/ oF)

Figure 1. The axisymmetric model of the pipe with the thermal and pressure loadings.

Instructions:

1. Enter ANSYS in your working directory using pipe-direct as the jobnameor:

Clear the database, and change the jobname topipe-direct.

2. Read input from pipe-th.inp to create the 2D axisymmetric model:

/INPUT, pipe-th, inp

3. Add an axisymmetric coupled field element type (PLANE13).

- Main Menu > Preprocessor > Element Type > Add/Edit/Delete

Select Coupled Field and Vector Quad 13, then [OK]

4. Modify element options for structural / thermal, axisymmetric:

[Options]

K1 = UX UY TEMP AZ K3 = Axisymmetric

[OK]

[Close]

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- Or issue:

ET, 1, PLANE13

KEYOPT, 1,1,4

KEYOPT, 1,3,1

5. Change the title:- Utility Menu > File > Change Title

/TITLE = 2D AXI-SYMM THERMAL ANALYSIS W/ COV. LOADING

ESIZE=0.125

[OK]

6. Mesh the model using mapped meshing with 2D quad elements:

- Main Menu > Preprocessor > MeshTool

Pick [Set] under Size Controls: Global

SIZE = 0.25/2, then [OK]

Select Mapped, then [Mesh]

[Pick All]- Or issue:

MSHAPE, 0, 2D

MSHKEY, 1

ESIZE, 0.25/2

AMESH, ALL

7. Specify material property data (refer to Practice 9A Handout)

8. Apply convection loads to the solid model lines:

- Use either the manu path or issue:

SEL, 2, CONV, 0.69e-4, , 70

SEL, 6, CONV, 0.69e-4, , 70

SEL, 10, CONV, 0.69e-4, , 70

SEL, 9, CONV, 0.28e-3, , 450

SEL, 13, CONV, 0.28e-3, , 450

9. Apply internal constant pressure of 1000 psi to the internal lines of the pipe:

- Use either the manu path or issue:

SEL, 9, PRES, 1000

SEL, 13, PRES, 1000

10. Apply symmetry boundary condition on lines at Y = 0:

- Main Menu > Preprocessor > Loads > -Loads- Apply > Displacement > -Symmetry B.C- On

lines +

Select the appropriate lines (i.e. lines 2, 5 and 11), then [OK]

- Or issue:

DL, 3, , SYMM

DL, 5, , SYMM

DL, 11, , SYMM

11. Couple UY DOF on nodes at Y = 1:

11a). Select nodes a Y= 1 using the Select logic:- Utility Menu > Select >Entities:

Select Nodes and By Location,

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Select Y Coordinates

Set Min,Max to 1, then [OK]

- Or issue:

NSEL, S, LOC, Y, 1

11b). Define a UY DOF couple set on the select set of nodes:

- Main Menu > Preprocessor >Coupling / Ceqn > Couple DOFs +: [Pick All]

Let: NSET = 1

Set Lab = UY

[OK]

- Utility Menu > Select >Everything

- Or issue:

CP, 1, UY, ALL

ALLSEL, ALL

12. Save the database and obtain the solution.- Use either the Manu path, or issue:

SAVE

/SOLU

SOLVE

13. Enter the general postprocessor and review the results:

13a). Plot displacement:

- Main Manu > General Postproc > Plot Results > -Contour Plot Nodal Solu

Pick DOF solution and Translation USUM

Select Def + undef edge, then [OK].

- Or issue:

/POST1

PLNSOL, U, SUM, 2, 1

13b). Plot von Mises stress:


Pick Stress and von Mises SEQV select Def shape only, then [OK].

- Or issue:

PLNSOL, S, EQV

13c). Plot radial stress:


Pick Stress and X-direction SX, then [OK].

- Or issue:

PLNSOL, S, X

13d). Expand the axisymmetric radial stress 90 degrees about the Y axis and reflect about the x-

z plane:

- Utility Manu > PlotCtrls > Style > Symmetry Expansion > 2D Axi-Symmetric

Pick 1/4 expansion and set reflection to Yes, then [OK].

- Utility Manu > PlotCtrls > Pan, Zoom, Rotate [ISO]

- Or issue:

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/EXPAND, 9, AXIS, , , 10, , 2, RECT, HALF, , 0.00001

/VIEW, 1, 1, 1, 1

/REPLOT

13e). Plot longitudinal (axis) stress:


Pick Stress and Y-direction SY, then [OK].- Or issue:

PLNSOL, S, Y

13f). Plot circumferential (hoop) stress:


Pick Stress and Z-direction SZ, then [OK].

- Or issue:

PLNSOL, S, Z

14. Save and exit ANSYS

- Pick the QUIT button from the Toolbar (or select: Utility Menu > File > Exit ) Select Save Everything

[OK].

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__ANSYSPrac-9c.pdf