ansys lug and pin stress analyses

Non-Linear Static Analysis of a Solid Lug

Fergyanto E. Gunawan ([email protected])

Department of Mechanical Engineering

Toyohashi University of Technology

Objectives:

� Using solid element; element type SOLID186.

� Create a solid lug.

� Compare the computation time of following cases:

– Nonlinear SOLID186, TARGE170 and CONTA174

– Linear PLANE182 and LINK1

� Review the results

DISCLAIMER: This module is based on the example problem presented in MSC.Natran 120 Exercise Workbook - Release 9.0. However,

a number of modi�cations is made to tailor the need of ANSYS 9.0.


Model Description

Figure 1 is a geometric representation of the lug shown on the title page; and its also shows the pin-bearing

load scenario that will be considered.

R5

R2.5

15.0

1.0 psit = 1.0

Figure 1: The simpli�ed lug and its loading conditions.

FEG 2


Pre-Processing Phase:

1. De�ne some parameters: ANSYS Pulldown Menu

Parameters B Scalar Parameters

Selection PI = ACOS(-1.0)

Accept

2. Select an element type: ANSYS Main Menu

Preprocessor B Element Type B Add/Edit/Delete

Add

Solid 20node 186

OK

Close

3. De�ne material properties: ANSYS Main Menu

Preprocessor B Material Props B Material Models

Structural B Linear B Elastic B Isotropic

EX 10.0E+06

PRXY 0.3

OK

Material B Exit

4. Create two rectangles: ANSYS Main Menu

Preprocessor B Modeling B Create B Areas B Rectangle B By 2 Corners

WP X 0.0

FEG 3


WP Y 0.0

Width 5.0

Height 5.0

Apply

WP X 5.0

WP Y 0.0

Width 10.0

Height 5.0

OK

5. Create two circles: ANSYS Main Menu

Preprocessor B Modeling B Create B Area B Circl B Partial Annulus

WP X 0.0

WP Y 0.0

Rad-1 0.0

Theta-1 0.0

Rad-2 5.0

Theta-2 180

Apply

WP X 0.0

WP Y 0.0

Rad-1 0.0

Theta-1 0.0

Rad-2 2.5

Theta-2 180

FEG 4


OK

6. Turn on some entities numbers: ANSYS Pulldown Menu

PlotCtrls B Numbering

LINE Line numbers � on

AREA Area numbers � on

NODE Node numbers � on

OK

7. Add Area A1 and Area A3: ANSYS Main Menu

Preprocessing B Modeling B Operate B Booleans B Add B Areas

< Pick Areas A1 and A3 >

OK

You should see the new area which has a number of A5

8. Subtract Area A5 by A4: ANSYS Main Menu

Preprocessing B Modeling B Operate B Booleans B Substract B Areas

< Pick Area A5 >

OK

< Pick Area A4 >

OK

You should see the new area which has a number of A1

9. Merges coincident Keypoints: ANSYS Main Menu

Preprocessor B Numbering Ctrls B Merge Items

FEG 5


Label Type of item to be merge Keypoints

OK

After the substraction and merging the coincident keypoints, we obtain a model, presented in Fig. 2,

that has two areas: A1 and A2.

Figure 2: The model after the area substraction and merging of the coincident nodes.

10. Create two keypoints: ANSYS Main Menu

Preprocessor B Modeling B Create B Keypoints B In Active CS

NPT Keypoint number 100

X, Y, Z Location in active CS 0.0 0.0 0.0

Apply

NPT Keypoint number 200

X,Y,Z Location in active CS 5.0*COS(3/4*PI) 5.0*SIN(3/4*PI) 0

OK

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11. Create three lines: ANSYS Main Menu

Preprocessor B Modeling B Create B Lines B Lines B Straight line

< Pick Keypoints: 100, and then 200 >



Cancel

12. Cut the Area A1 into two areas: ANSYS Main Menu

Preprocessing B Modeling B Operate B Booleans B Divide B Area by Line

< Pick Area A1 >

OK

< Pick Line L1 >

Apply

You should see the new area of Area A4. Cut the area by Line L8:

< Pick Area A4 >

OK

< Pick Line L8 >

Apply

You should see the new area of Area A5. Cut the area by Line L10:

< Pick Area A5 >

OK

< Pick Line L10 >

OK

FEG 7


Figure 3: The lug model that breaking down into �ve areas.

13. Control the mesh density: ANSYS Pulldown Menu

Preprocessor B Meshing B MeshTool

Lines Set

Pick All

NDIV No. of element divisions 4

Apply

< Pick Lines L5 and L7 >


OK

Close

14. Extrude the areas: ANSYS Main Menu

Preprocessor B Modeling B Operate B Extrude B Areas B By XYZ O�set

FEG 8


Pick All

DX,DY,DZ O�sets for extrusion 0.0 0.0 0.5

OK

15. Merges coincident Keypoints: ANSYS Main Menu


Label Type of item to be merge Keypoints

OK

16. Change the viewpoint to the isometric viewpoint: ANSYS Toolbars

< Click >

17. Sweep mesh all volumes: ANSYS Main Menu

Preprocessor B Meshing B Mesh B Volume Sweep B Sweep

Pick All

Note I A pin having a radius of 2.5 in (See following �gure) is inserted into the lug hole

to prevent the lug being moved when an uniform stress is applied onto the lug

right end. Therefore, the target elements must be installed onto the surface of the

lug hole, and the contact element must be installed onto the surface of the pin

surface. Those nodes in the area where the target and the contact elements will

be created should be grouped for simplicity.

Pin

Lug

Target elements Contact elements

18. Change the active coordinate system: ANSYS Pulldown Menu

Workplane B Change Active CS To B Global Cylindrical

FEG 9


Figure 4: The meshed lug.

19. Select and groups nodes: ANSYS Pulldown Menu

Select B Entities

Nodes

By Location

� X coordinates

Min, Max 2.5, 2.5

Apply

Plot

OK

Group those nodes:

Select B Comp/Assembly B Create Component

Cname Component name cNodeTarget

Entity Component is made of Nodes

FEG 10


Close


Workplane B Change Active CS To B Global Cartesian

21. Activate everything: ANSYS Pulldown Menu

Select B Everything

22. Create a quarter of a solid cylinder: ANSYS Main Menu

Preprocessor B Modeling B Create B Volumes B Cylinder B Partial Cylinder

WP X 0.0

WP Y 0.0

Rad-1 0.0

Theta-1 0.0

Rad-2 2.5

Theta-2 90

Depth 0.5

OK

23. Before we mesh the quarter solid cylinder, we should bring the volume into our focus, and removes all

other volumes: ANSYS Pulldown Menu

Select B Entities

Volumes

OK

< Click the quarter of a cylinder >

OK

FEG 11


A quarter of a cylinder

Figure 5: A quarter of a solid cylinder for modeling the pin.

Now, select all lines and areas constructed the volume:

Select B Below B Selected Volumes

Plot B Lines

You should obtain a �gure as shown in Fig. 6. Before we mesh the volume, similar to the meshing

of the previous volume, we should control the mesh density along the boundary; in this case, mesh

density on lines: L36, L36, and L40.

Figure 6: The quarter of a cylinder.

24. Control mesh density on lines L36, L37, and L40; and mesh the new volume: ANSYS Main Menu

Preprocessor B Meshing B MeshTool

Lines Set

< Click Line L40 >

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Apply

< Click Line L36 and L37 >


OK

Mesh: Volumes

Shape: � Hex/Wedge

Shape: � Sweep

Sweep

< Click the volume >

Close

You should obtain a �nite element mesh similar to that depicted in Fig. 7. In addition, you should

re ect the mesh to obtain a meshed half cylinder.

Figure 7: The meshed of the quarter of a cylinder.

25. Re ect the volume and all elements within the volume: ANSYS Main Menu

Preprocessor B Modeling B Re ect B Volumes

< Click the volumes >

OK

FEG 13


NOELEM Items to be re ected Volume and mesh

OK

26. Plot the elements: ANSYS Pulldown Menu

Plot B Elements

You should obtain a mesh similar to that shown in Fig. 8. As you can see, there are a number of

coincidents nodes, encircled noded in the �gure; therefore, those nodes should be merged.

Figure 8: The coincident nodes, encircled nodes, on the half cylinder

27. Merge the coincident nodes: ANSYS Main Menu


Label Type of item to be merge Nodes

OK


Workplane B Change Active CS To B Global Cylindrical

29. Select and groups nodes: ANSYS Pulldown Menu

Select B Entities

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Nodes

By Location

� X coordinates

Min, Max 2.5, 2.5

Apply

Plot

OK

30. Group those nodes: ANSYS Pulldown Menu

Select B Comp/Assembly B Create Component

Cname Component name cNodeContact


Close


Workplane B Change Active CS To B Global Cartesian


Select B Everything

Plot B Areas

You should obtain a solid model of a pinned lug (see Fig. 9).

33. Select everything: ANSYS Puldown Menu

Select B Everything

Plot B Elements

FEG 15


Figure 9: The solid model of a pinned lug.

Note I We have two groups of nodes: cNodeTarget and cNodeContact. Therefore, we now

are ready to create both the target elements and the contact elements. ANSYS

9.0 has a wizard to automatically create both type of elements: TARGE170 and

CONTA174.

34. Create the target elements and the contact elements: ANSYS Main Menu

Preprocessor B Modeling B Create B Contact Pair

Press this button to start the wizard for creating the contact and the target elements

FEG 16


Select the target nodes

1

2

1

2

Select the contact nodes

FEG 17


Close the wizard.

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Solution Phase

1. De�ne the analysis type: ANSYS Main Menu

Solution B Analysis Type B New Analysis

[ANTYPE] Type of analysis: � Static

OK

2. Activate the front view: ANSYS Toolbars

< Click >

3. Select and grouping the nodes: ANSYS Pulldown Menu

Select B Entities

Nodes

By Location

� Y coordinates

0, 0

Apply

Plot

Select B Entities B Comp/Assembly B Create Components

Cname Component name cNodeBottom


Apply

� X coordinates

0, 0

� Resellect

FEG 19


Apply

Plot


Cname Component name cNodeCenter


OK

Select B Entities

� Z coordinates

0, 0

Apply

Plot


Cname Component name cNodeFront


Apply

Select B Everything

Plot B Nodes

4. Apply the boundary condition: ANSYS Main Menu

Solution B De�ne Loads B Apply B Structural B Displacement B On Nodes Components

� List of Items cNodeBottom

Apply

Lab2 DOFs to be constrained UY

FEG 20


Apply

� List of Items cNodeFront

Apply

Lab2 DOFs to be constrained UZ

Apply

� List of Items cNodeCenter

Apply

Lab2 DOFs to be constrained ALL DOF

OK

5. Activate the isometric view: ANSYS Toolbars

< Click >

6. Apply the uniform pressure: ANSYS Main Menu

Solution B De�ne Loads B Apply B Structural B Pressure B On Area

< Click Area A13 >

OK

VALUE Load PRES value -100.0

OK

Note I If you have done any selection command, for example, selecting certain lines,

nodes, elements or so on, you should remember to reselect entire model before the

run.


FEG 21


Select B Everything

8. Solve the problem: ANSYS Main Menu

Solution B Solve B Current LS

OK

Close

Post Processing Phase

1. Plot deformation: ANSYS Main Menu

General Postproc B Plot Results B Deformed Shape

KUND Items to be plotted: � Def shape only

OK

The result is shown Fig. 10; in the left-top corner, it tells that the DMX, the maximum displacement,

is 0.474E-03 in.

Figure 10: The deformation of a pinned lug.

FEG 22


2. Plot the von-Mises stress of a partial model:

(a) Activate the isometric view: ANSYS Toolbars

< Click >

(b) Activate the area number: ANSYS Pulldown Menu

PlotCtrls B Numbering

AREA Area numbers � on

(c) Select the volumes: ANSYS Pulldown Menu

Select B Entities

Volumes

OK

< Click A5 and A16 >

OK

(d) Select everything within the volumes: ANSYS Pulldown Menu

Select B Everything Below B Selected Volumes

(e) Plot the stress: ANSYS Main Menu

General Postproc B Plot Results B Nodal Solu

Nodal Solution B Stress B von Misses stress

OK

3. The appendix presents a di�erent approach that utilizes a linear solution PLANE183 and LINK1. the

results are compared in the table.

Table 1: ComparisonElements Computation Time (s) �x at a node (psi)PLANE183, LINK1 0.2778E-03 44.22SOLID186, TARGE170, CONTA174 0.3611E-02 (13� longer) 43.85

FEG 23


Figure 11: The von-Mises stress of the partial model.

Figure 12: the von-Mises stress for PLANE183 and LINK1 elements

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Batch Mode

Preamble:

/clear ! Delete everything

/view, 1, 1, 1, 1, ! Change the view to isometric view

PI = acos(-1.0) ! Define a constant of PI

Pre-Processing Phase

1. Enter the preprocessing phase:

/prep7 ! Enter preprocessing phase

The GUI counterpart of the above command is

ANSYS Main Menu B Preprocessor

2. Select an element type:

et, 1, solid186 ! Select 20 nodes solid186 element type

3. De�ne the material properties:

mp, ex, 1, 10.0E+06 ! Young’s modulus

mp, nuxy, 1, 0.3 ! Poisson’s ratio

4. Create some areas:

rectng, 0.0, 5.0, 0.0, 5.0 ! Create a rectangle; has a number of A1

rectng, 5.0, 15.0, 0, 5 ! Create a rectangle; has a number of A2

pcirc, 0.0, 5.0, 90, 180 ! Create a half circle; has a number of A3

pcirc, 0.0, 2.5, 0, 180 ! Create a half circle; has a number of A4

5. Joint areas and cut the hole:

aadd, 1, 3 ! Add A1 with A3, produces A5

asba, 5, 4 ! Cut A5 with A4, produces A1

Only two areas are left: A1 and A2.

6. Some Keypoints reside in the same locations; therefore, joint them:

nummrg, kp

Joining the keypoints will also joint the lines connecting those keypoints.

FEG 25


7. Create two Keypoints:

k, 100, 0.0, 0.0, 0.0

k, 200, 5.0*cos(0.75*PI), 5.0*sin(0.75*PI), 0.0

8. Create three lines:

l, 100, 200 ! visual check, L1

l, 100, kp(0.0, 5.0, 0.0) ! visual check, L8

l, 100, kp(5.0, 5.0, 0.0) ! visual check; L10

Note I The kp is an intrinstic function that returns the number of the keypoint at a given

location. The complete command is

presentKeypoint = kp(x, y, z)

As you may guess, to get the node number at a given location (x; y; z), the intrinsic

function is

presentNode = node(x, y, z)

9. Cut the area:

asbl, 1, 1 ! Divides A1 with L1; produces A4 (visual check)



10. Control the mesh-size:

lesize, all, , , 4 ! Break down all lines into 4 elements

lesize, 5, , , 6 ! For L5 and L7, use 6 elements

lesize, 7, , , 6 !

11. Create volumes:

voffst, 1, 0.5*1.0 ! Offset A1 to form a volume





12. Merge the coincident Keypoints:

nummrg, kp

13. Mesh all volumes:

vsweep, all ! Mesh all volumes

FEG 26


14. Group some nodes to form creating target elements:

csys, 1 ! Activate the cylidrical coordinate system

nsel, , loc, x, 2.5, 2.5 ! Select nodes at location r = 2.5

cm, cNodeTarget, node ! Groups those nodes, the group name is cNodeTarget

csys, 0 ! Activate the cartesian coordinate system

alls ! Select everything

15. Create a quarter of volume for making the pin:

cyl4, , , 0.0, 0.0, 2.5, 90, 0.5*1.0 ! Create a quarter cylinder, V6

16. Mesh the pin:

lesize, 40, , , 8 ! 8 elements on L40; needs visual check



vsweep, 6 ! Mesh volume V6

17. Re ect the volumes and the elements

vsymm, x, 6 ! Create V7 and also elements

18. Merge the coincident nodes on the pin:

vsel, , volu,, 6 ! Select V6

vsel, a, volu,, 7 ! In addition, select V7

nslv,, 1 ! Select nodes on selected volumes, in this case V6 and V7

nummrg, node ! Joint the coincident nodes

19. Group the nodes

csys, 1 ! Activate the cylindrical coordinate system

nsel, , loc, x, 2.5, 2.5 ! Select nodes on location r = 2.5

cm, cNodeContact, node ! Group those nodes, the name is cNodeContact

csys, 0 ! Activate the Cartesian coordinate system


20. Create the target elements:

et, 2, targe170 ! Create element type of targe170

nsel,, node,, cNodeTarget ! Select nodes: cNodeTarget

esln, s, 0 ! Select the elements attached to those nodes

esurf ! Create targe170 elements

FEG 27


Note I The command esln allows us to select elements for a given selected nodes. The

command is mnemonic of Elements SeLected Nodes. Therefore, it is logical to

speculate the existence of : nsll (nodes selected lines), nslv (nodes selected

volumes), nsle (nodes selected elements), esln (elements selected nodes), and so

on; including the best one, of course, is wslf (wife selected by fate).

21. Create the contact elements:

et, 3, conta174 ! Create element type of conta174

nsel,, node,, cNodeContact ! Select nodes: cNodeContact

esln, s, 0 ! Select the elements attached to those nodes

esurf ! Create conta174 elements


22. Leave the pre-processing phase:

finish ! Get out the preprocessing phase

Solution

1. Enter the solution phase:

/solu

2. Select the analysis type:

antype, static

3. Apply the boundary constraints:

nsel,, loc, y, 0.0, 0.0 ! Select nodes at location y = 0.0

dsym, symm, y ! Apply the constraints on those nodes

nsel, r, loc, x, 0.0, 0.0 ! Reselect the previous selected nodes only at location x = 0.0

d, all ,all ! Apply the constraints on those nodes

nsel,, loc, z, 0.0, 0.0 ! Select nodes at z = 0.0

dsym, symm, z ! Apply the symmetry constraints

4. Apply pressure:

asel,, loc, x, 15.0, 15.0 ! Select area at x = 15.0, end of the lug

sfa, all, , pres, -100.0 ! Apply uniform pressure

5. Select everything:

FEG 28



6. Solve

solve

7. Leave the solution phase

finish

Appendix

Code for Linear Analysis

/clear

*afun, deg

pi = acos(-1.0)

/prep7

et, 1, plane183, , , 3

r, 1, 1.0

mp, ex, 1, 10.0E+06

mp, nuxy, 1, 0.3

rectng, 0.0, 5.0, 0.0, 5.0

rectng, 5.0, 15.0, 0, 5

pcirc, 0.0, 5.0, 90, 180

pcirc, 0.0, 2.5, 0, 180

aadd, 1, 3

asba, 5, 4

nummrg, kp

k, 100, 0.0, 0.0, 0.0

k, 200, 5.0*cos(0.75*pi), 5.0*sin(0.75*pi), 0.0

l, 100, 200

l, 100, kp(0.0, 5.0, 0.0)

l, 100, kp(5.0, 5.0, 0.0)

asbl, 1, 1

asbl, 4, 8

asbl, 5, 10

lesize, all, , , 4

lesize, 5, , , 6

lesize, 7, , , 6

amesh, all

et, 2, link1

FEG 29


r, 2, 100

type, 2

real, 2

n, 1000, 0.0, 0.0, 0.0

angleInc = 90/8

angle = 180

iNode = 1000

*do, i, 1, 8

jNode = node( 2.5*cos(angle), 2.5*sin(angle), 0.0 )

e, iNode, jNode

angle = angle - angleInc

*enddo

finish

/solu

type, static

dcum, add

nsel,, loc, y, 0.0, 0.0

dsym, symm, y

nsel, r, loc, x, 0.0, 0.0

d, all ,all

lsel,, loc, x, 15.0, 15.0

sfl, all, pres, -100.0

sftran

alls

*get, timeStart, ACTIVE, 0, time, wall

solve

*get, timeEnd, ACTIVE, 0, time, wall

finish

/post1

nodeOutput = node(0, 5.5, 0.0)

*get, nodeStress, NODE, nodeOutput, S, EQV

*cfopen, output, dat

*vwrite, timeEnd - timeStart, nodeStress

(E15.4, 2X, E15.4)

*cfclose

finish

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ansys lug and pin stress analyses