2-D Cylindrical Roller Contact

Chapter 1: 2-D Cylindrical Roller Contact

1 2-D Cylindrical Roller Contact

Summary 19

Introduction 20

Solution Requirements 20

Analytical Solution 20

FEM Solutions 21

Modeling Tips 25

Pre- and Postprocess with SimXpert 28

Input File(s) 68

19CHAPTER 1

2-D Cylindrical Roller Contact

SummaryTitle Chapter 1: 2-D Cylindrical Roller Contact

Contact features • Advancing contact area• Curved contact surfaces• Deformable-deformable contact• Friction• Comparison of linear and parabolic elements

Geometry 2-D Plane strain (units: mm)

• Block height = 200• Block width = 200• Cylinder diameter =100• Thickness = 1

Material properties

Linear elastic material

Analysis type Quasi-static analysis

Boundary conditions • Symmetric displacement constraints along vertical symmetry line.• Bottom surface of the foundation is fixed

• Contact between cylinder and block

Applied loads Vertical point load

Element type 2-D Plane strain• 8 -node parabolic elements• 4-node linear elements

Contact properties Coefficient of friction and FE results 1. Plot of normal contact pressure against distance from center of contact

2. Plot of tangential stress against distance from center of contact3. Plot of relative tangential slip against distance from center of contact

F

Ecylinder 210kN mm2= Eblock 70kN mm2= cylinder block 0.3= =

ux uy 0= =

F 35kN=

0.0= 0.1=

0 1 2 3 4 5 6 7 80

1000

2000

3000

4000

5000

SOL 400 Contacted Surface

SOL 400 Contacting Surface

Analytical

Distance (mm)

Contact Pressure N/mm2

MD Demonstration Problems

CHAPTER 120

IntroductionA steel cylinder is pressed into an aluminum block. It is assumed that the material behavior for both materials is linear elastic. The cylinder is loaded by a point load with magnitude in the vertical direction. A 2-D approximation (plane strain) of this problem is assumed to be representative for the solution. An analytical solution for the frictionless case is known - (Ref: NAFEMS, 2006, Advanced Finite Element Contact Benchmarks, Benchmark 1 2D Cylinder Roller Contact).

Solution RequirementsThere are two solutions: one using a friction coefficient of 0.1 between the cylinder and block and one frictionless.

• Length of contact zone• Normal pressure distribution as function of distance (x-coordinate) along the contact surface• Tangential stress distribution as function of distance along the contact surface

These solutions demonstrate:

• More elements near the contact zone• Which surface is treated as master (contacting) and slave (contacting)

The analysis results are presented with linear and parabolic elements.

Analytical SolutionAn analytical solution for this contact problem can be obtained from the Hertzian contact formulae (Hertz, H., Über die Berührung fester elasticher Körper. J. Reine Angew. Mathm. 92, 156-171, 1881) for two cylinders (line contact). The maximum contact pressure is given by:

where is the applied normal force, the combined elasticity modulus, the length of the cylinder and the

combined radius.

The contact width is given by:

Using the normalized coordinate with the Cartesian x-coordinate, the pressure distribution is given by:

The combined elasticity modulus is determined from the modulus of elasticity and Poisson’s ratio of the cylinder and

block , , , and , as follows:

F 35kN=

pmax

FnE*

2BR*------------------=

Fn E* B R*

2a

a8FnR*

BE*-----------------=

x a= x

p pmax 1 2–=

Ecylinder Eblock cylinder block

E*2EcylinderEblock

Eblock 1 cylinder2– Ecylinder 1 block

2– +---------------------------------------------------------------------------------------------------------------=

21CHAPTER 1


The combined radius of curvature is evaluated from the radius of curvature of the cylinder and block and

, as follows:

For the target solution, the block is approximated with an infinitely large radius. The combined radius is then evaluated as:

Using the numerical parameters for the problems the following results are obtained:

Note that half the contact length is equal to 6.21 mm which corresponds to approximately 7.1 degrees of the ring. Hence, it is clear that, in order to simulate this problem correctly, a very fine mesh near the contact zone is needed.

FEM SolutionsA numerical solution has been obtained with MD Nastran’s solution sequence 400 (SOL 400) for the element mesh shown in Figure 1-1 using plane strain linear elements. The elements in the entire cylinder and entire block have been selected as contact bodies. Contact body IDs 5 and 6 are identified as a set of elements of the block and cylinder respectively as:

BCBODY 5 2D DEFORM 5 0 .1BSURF 5 1 2 3 4 5 6 7...

and

BCBODY 6 2D DEFORM 6 0 .1BSURF 6 1242 1243 1244 1245 1246 1247 1248...

Furthermore, the BCTABLE entries shown below identify that these bodies can touch each other:

BCTABLE 0 1 SLAVE 6 0. 0. .1 0. 0 0. 0 0 0 MASTERS 5BCTABLE 1 1 SLAVE 6 0. 0. .1 0. 0 0. 0 0 0 MASTERS 5

Thus, any deformable contact body is simply a collection of mutually exclusive elements and their associated nodes. The order of these bodies is important and is discussed later. For the simulations with friction, a bilinear Coulomb model is used (FTYPE = 6). The slave or contacting nodes are contained in the elements in the cylinder, whereas the master nodes or nodes or contacted segments are contained in the elements in the block.

Rcylinder

Rblock

R*RcylinderRblock

Rcylinder Rblock+-------------------------------------------=

R* RcylinderRblock

Rcylinder Rblock+-------------------------------------------

Rblock lim Rcylinder= =

a 6.21mm=

pmax 3585.37N mm2=


CHAPTER 122

Figure 1-1 Element Mesh Applied in Target Solution with MD Nastran

Nonlinear plane strain elements are chosen by the PSHLN2 entry referring to the PLPLANE option as shown below.

PLPLANE 1 1PSHLN2 1 1 1 ++ C4 PLSTRN L +

Herein referred to as plane strain quad4 elements (PLSTRN QUAD4) or (PLSTRN QUAD8) for the linear and parabolic elements respectively listed in Table 1-1. All elements are 1 mm thick in the out-of-plane direction.

The material properties are isotropic and elastic with Young’s modulus and Poisson’s ratio defined as:

$ Material Record : steelMAT1 1 210000. .3$ Material Record : aluminumMAT1 2 70000. .3

The nonlinear procedure used is:

NLPARM 1 1 PFNT

Here the PFNT option is selected to update the stiffness matrix during every iteration using the full Newton-Raphson iteration strategy; the default convergence tolerance values (0.01) will be used. The convergence method and tolerances may be specified explicitly as shown here since they will be discussed later.

Table 1-1 Applied Element Types in Numerical Solutions

SOL 400

linear PLSTRN QUAD4

parabolic PLSTRN QUAD8

X

Y

Z

Contact Body ID 5 Element IDs 1 to 1241

Contact Body ID 6 Element IDs 1242 to 2641

Steel Cylinder

Aluminium Block

23CHAPTER 1


The obtained lengths of the contact zones are listed in Table 1-3. The exact length of the contact zone cannot be determined due to the discrete character of contact detection algorithms (nodes are detected to be in contact with an element edge for 2-D, element face for 3-D). It is clear, however, that the numerical solution is in good agreement with the analytical one.

The deformed structure plot (magnification factor 1.0) is shown in Figure 1-2. A plot of the Hertzian contact solution for the pressure along the contact surface is obtained with linear and parabolic elements as shown in Figure 1-3 and Figure 1-4.

Figure 1-2 Deformed Structure Plot at Maximum Load Level (magnification factor = 1)

Table 1-2 Nonlinear Control Parameters

1 2 3 4 5 6 7 8 9 10

NLPARM 1 1 PFNT UP +pb1

+pb1 1.00E-02 1.00E-02 1.00E-05

Table 1-3 Length of the Contact Zone and Pmax

amin(mm)

aavg(mm)

amax(mm)

Error(%)

Pmax (N/mm2)

Error(%)

linear 5.99 6.33 6.67 2.6 3285 -8.38

parabolic 5.88 6.08 6.28 -1.5 3583 -0.05

Contacted Nodes

Contacting Nodes

amin

amax


CHAPTER 124

Figure 1-3 Comparison of Analytical and Numerical Solutions for Linear Elements without Friction

Figure 1-4 Comparison of Analytical and Numerical Solutions for Parabolic Elements without Friction

The contact pressure plotted for the contacting nodes shows, even with this mesh density, an oscillating type of behavior. This is reduced for the parabolic elements. Generating the same plots along the contacted nodes produces a smoother curve.

Numerical solutions have also been obtained with a friction coefficient of 0.1 (bilinear Coulomb). The contact normal and tangential stress along the contacting nodes are shown in Figure 1-5.

All stresses show an oscillating type of behavior. This can be improved by refining the mesh in the contact zone.

0 1 2 3 4 5 6 7 80

1000

2000

3000

4000

5000



Analytical

Distance (mm)


0 1 2 3 4 5 6 7 80

1000

2000

3000

4000

5000



Analytical

Distance (mm)


25CHAPTER 1


Figure 1-5 Normal and Tangential Stress Along Contact Surface

Modeling Tips

About ConvergenceAlthough the nonlinearity of the force-displacement relation in this problem is quite mild, looking more closely at the convergence of this problem will be useful for subsequent problems in this manual, and worthy of mention here as a matter of introduction. Table 1-4 controls the number of iterations in the Newton-Raphson process illustrated below in Figure 1-6.

Table 1-4 Convergence Output

Load Step No. Inc IRT

Error Factors

Disp Load Work

1 1 1 1.00E+00 9.78E-01 9.78E-01

1 1 2 3.70E+00 8.83E-01 4.57E+00

1 1 3 2.80E+00 6.83E-01 3.98E+00

1 1 4 1.43E+00 3.81E-01 2.26E+00

1 1 5 4.96E-01 7.28E-02 8.84E-01

1 1 6 3.72E-04 1.51E-02 9.98E-04

1 1 7 6.00E-05 2.69E-05 8.69E-05

Distance (mm)

Contact Stress N/mm 2

0 1 2 3 4 5 6 7 80

1000

2000

3000

4000

5000

Tangential Parabolic

Tangential Linear

Pressure Parabolic

Pressure Linear


CHAPTER 126

Figure 1-6 Newton - Raphson Path for Load-Displacement Curve

At the beginning of the analysis (Point A in Figure 1-6), the tangent modulus (slope of load-displacement curve) is used to project to the applied load to Point B, which does not satisfy the convergence criteria. Then equilibrium is re-established at Point C, and a new slope is computed. The Newton-Raphson iterative procedure continues until the convergence tolerances are satisfied, Point D. The convergence criteria are based upon displacement, load or work either individually or in some combination. The Newton-Raphson iterative scheme is recommended for all SOL 400 analyses because the degree of nonlinearity is typically significant. For the parameters in Table 1-3, the output (Table 1-4) shows the following convergence characteristics. The percent sign helps to locate the line in the output file. In this case, the criteria used is both the displacement, U, and load, P - specified through the UP keyword for the convergence type on the NLPARM command - with a value of 0.01 for each. This means that both relative displacement and load measures (error factors) must be below 0.01 for convergence to be permitted. This can be seen in Figure 1-7.

In this case, there is no checking on the work, even though it has a low tolerance.

Figure 1-7 Error Factors For Each Iteration

About the Order of Contact Bodies

The nug_01aw.dat input file changes the order of the contact body detection, in which the coarser mesh (block) is the contacting surface. Although acceptable to the contact algorithm, the results are degraded since it is best to have

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

10000

20000

30000

40000

50000

60000

Applied Load = 17500

Newton-Raphson PathF , v

Displacement v (mm)

y2

F (N)Load y

Point A

Point B

Point C

Point D

-5

-4

-3

-2

-1

0

1

Log(epsw)

Log(epsp = epsu)

Log(work)

Log(load)

Log(disp)

27CHAPTER 1


the body with the most nodes as the contacting body. Run nug_01aw.dat to see the differences as shown in Figure 1-8.

Figure 1-8 Deformed Mesh of Different Contact Body Ordering

Contacting Nodes

Contacted Nodes

Steel Cylinder

Aluminium Block

nug-01aw.dat

Contacting Nodes

Contacted Nodes

Steel Cylinder

Aluminium Block

nug-01am.dat


CHAPTER 128

Pre- and Postprocess with SimXpert

UnitsAll data imported or created in MSC SimXpert is assumed to be in a single consistent system of units, as specified in the Unit Manager. It is important to specify the appropriate units prior to importing any unitless analysis files, such as an MD Nastran bulk data file, or creating materials, element properties, or loads. This is so that the MSC SimXpert user is assisted in being consistent with the use of numerical quantities that have units. The system of units is specified in a dialog accessed by selecting Tools: Units Manager.

For the illustration below, the geometry is created, meshed with linear elements using frictionless contact, and finished by comparing results with the analytic solution.

a. Tools

b. Options

c. Units Manager

d. Basic Units

a

b

d

c

29CHAPTER 1


Create a Part for the BlockParts are the main components of a model and may be used to specify specific attributes (geometry, properties etc.). For example, here the part/block, is created (bottom right) that will be later used by picking the part from the model tree in the Model Browser (bottom left). We will find that in defining material properties picking parts from the model tree is easier than trying to pick a group of elements. Later the last part, cylinder, is created.

a. Assemble

b. Create Part

c. block; click OK

a

b

c


CHAPTER 130

Create the Block GeometryThe geometry of the part/block, is created here and results in a simple rectangular shaped object. More geometry is added to this part in subsequent steps.

a. Geometry

b. Filler

c. X, Y, Z Input enter 0,200,0; click OK

X, Y, Z Input enter 30,200,0; click OK



a

b

c

c

p ( p )

31CHAPTER 1


Create a Curve to Define a Surface EdgeContinuing to add geometry to the part/block, a curve (line) is created below the previous rectangle. This curve is used to generate a surface between the rectangle and line.

a. Geometry

b. Curve

c. X, Y, Z Input enter 0,100,0; click OK


OK

a

b

c

c


CHAPTER 132

Create a Surface Between Two CurvesNow the surface is generated between the curve on the bottom of the rectangle and the previously created curve. The part/block now contains two surfaces: a rectangle and quadrilateral.

a. Geometry

b. Filler

c. enter 2 Curves; click OK

a

b

c

33CHAPTER 1


Create a Surface by Defining Its VerticesAnother surface is added using one point and three vertices.

a. Geometry

b. Filler

c. Enter 1 point, 3 vertices; click OK

d. X, Y, Z Input enter 100,200,0; click OK

a

b

cd


CHAPTER 134

Create a Surface by Sweeping a CurveThe final surface added to the part/block, is created by sweeping the bottom horizontal curve downward for 100 mm.

a. Geometry

b. Sweep

c. Vector, two point normal, pick Curve, Length of Sweep; click OK

a

b

c

35CHAPTER 1


Stitch SurfacesFinally, all of the surfaces that comprise the part/block, are stitched together. Stitching surfaces creates congruent surfaces with aligned normals within a stitch tolerance. Unconnected or free edges are displayed in red whereas shared edges are displayed in green as shown below.

a. Geometry

b. Stitch

c. 4 bodies; click OK

a b

c

12

3

4


CHAPTER 136

Create a Part: CylinderNow the cylinder part is created.

a. Assemble

b. Create Part

c. Cylinder; click OK

a

b

c

• c. cylinder, OK

37CHAPTER 1


Create an ArcThe cylindrical surface is generated by an arc and a line. The arc is defined below.

a. Geometry

b. Arc

c. Dir-Radius 0,250,0;0,250,-1

d. Arc.1, 40,0,180 VERTEX(indicated); click OK

a

b

c

d


CHAPTER 138

Create a Curve Along a Line of SymmetryThe cylindrical surface is generated by an arc and a line. The line is defined below.

a. Geometry

b. Curve

c. 2 Vertices; click OK

ab

c

39CHAPTER 1


Break Line and Arc into Two Curves for Two SurfacesBefore generating a surface from these two curves, each curve (line and arc) is broken into two equal pieces respectively. This allows for generating two surfaces that ultimately generate different meshes.

a. Geometry

b. Edit Curve

c. Split

d. Parametric, 2 Curves; click OK

ab

c

d


CHAPTER 140

Create Surfaces from CurvesTwo surfaces (composing half of the cylinder) are generated from the curves previously constructed and are stitched together.

a. Geometry

b. Filler

c. 2 Curves, click OK (repeat for other 2 curves

d. Stitch, 2 surfaces; click OK

a

b

d

c

41CHAPTER 1


Create Mesh SeedsWith the parts completed, each curve of each surface is seeded prior to meshing. Here the curves that comprise the surface of the lower portion of the cylinder are seeded with element sizes that include uniform and biased seeds.

a. Meshing

b. Seed: Arrows on curves indicate direction for nonuniform mesh seed

c. Curve (seed as indicated in the 3 curves); click OK

ab

c


CHAPTER 142

Create MeshWith the curves of this surface seeded, a quadrilateral dominate mesh is created by using the surface mesher.

a. Meshing

b. Surface

c. Pick Surface, Mesh type and Method (indicated)

d. Element Size 1

e. Quad Dominant

f. OK

a

b

c

yp ( )

d

e

f

43CHAPTER 1


Create MeshThe top cylindrical surface is meshed with a quadrilateral dominate mesh and the cylindrical part meshing is complete.

a. Meshing

b. Surface

c. Pick Surface

d. Element Size 2.5

e. Quad Dominant

f. OK

a

b

c

d

e

f


CHAPTER 144

Create MeshThe block part consists of four surfaces that are now to be meshed with the smallest rectangular surface being mesh with uniform elements with the indicated size using a quadrilateral dominate mapped mesher.

a. Meshing

b. Surface

c. Pick Surface

d. Element Size 1.5

e. Quad Dominant

f. OK

a

b

c

d

e

f

45CHAPTER 1


Create Mesh SeedsThe upper quadrilateral surface curves are seeded appropriately, and the surface is meshed. A similar exercise is done for the lower quadrilateral surface (not shown).

a. Meshing

b. Seed: Arrows on Curves indicate direction for nonuniform mesh seed

c. Surface

OK

ab

b

bc


CHAPTER 146

Create MeshFinally, the lower rectangular surface of the block is meshed using the mapped mesher with uniform element sizes.

a. Meshing

b. Surface

c. Pick Surface

d. Element Size 5

e. Quad Dominant

f. OK

g. Pick Surface

h. Element Size 5

i. Quad Dominant

j. OK

a

b

c

d

e

f

g

h

i

j

47CHAPTER 1


Enforce Consistent NormalsAlthough the surfaces of the cylinder and block parts were stitched together, the surface mesher may create elements with inconsistent outward normals. This is the case here, and elements need to be fixed such that their outward normals all point in one direction (+z). This is done by showing the element normals, then fixing the normals using a reference element to set the normal direction. Continue this process until all normals are consistent; namely, they all point in the same direction.

a. Quality

b. Fix Elements

c. Normals

d. Show (Fix) Normals, click OK

a b

c

dd


CHAPTER 148

Define Material DataMaterials are defined by naming the material (steel and Al, respectively) while entering the properties. The problem statement required that the cylinder be made of steel and the block made of aluminum (Al). Since the basic units

selected have derived units of pressure (stress or modulus) as , Young’s modulus for the steel is entered as

and for aluminum. Poisson’s ratio is dimensionless and entered as for both materials.

a. Materials and Properties

b. Isotropic

c. steel, (properties); click OK

d. Al, (properties as shown); click OK

N mm 2

210x103 70x103 0.3

a

c d

b

• d. Al, (properties), OK

49CHAPTER 1


Define Material DataThe properties defined are now applied to the parts accordingly along with the planar element properties. Parts and materials are selected from the Model tree (not shown).

a. Materials and Properties

b. Plane

c. Plane Property (cylinder and block); click OK

a

b

c

c. Plane Property (cylinder and block), OK


CHAPTER 150

Contact Data for CylinderSince the cylinder will come into contact with the block, contact data needs to be specified. A contact body consists of a set of elements and their associated nodes that are mutually exclusive from other elements. While we know that only a small number of elements in the cylinder and block will ultimately come into contact, there is no need to specify this information; the contact algorithm completely determines where and when contact happens. Hence, our choice is simple. We will create two contact bodies, consisting of all elements in the two parts we have defined: the cylinder and block.

Although one might be tempted to only pick those elements suspected of coming into contact, it is best (and less time consuming) to just pick all the elements in the part as done here.

a. Loads and Boundary Conditions (LBC)

b. Deformable Body

c. Select cylinder; click OK

a

c

b

• b. Deformable Body

• c. Select cylinder, OK

51CHAPTER 1


Contact Data for BlockSimilar to the cylinder contact body, all elements in the block are selected to be in the next deformable contact body.


b. Deformable Body

c. Select block; click OK

• Define a deformable contact body for the block

ab

c


CHAPTER 152

Define Contact TablesAlthough a contact table is not necessary for this particular problem (see BCONTACT = ALLBODY in the QRG), one is used here for illustration. Here, the contact table indicates that all contact bodies touch each other, including themselves.

In general, contact tables describe how contact is to take place between contact bodies (touching, glue, none) and may change during the analysis by selecting different contact tables. A contact table allows one to define the coefficient of friction between the two touching bodies and its nonzero value overrides any previous value.


b. Table

c. BCTABLE_INIT; click OK

a

b

c

• c. BCTABLE_INIT

53CHAPTER 1


Define ConstraintsThe horizontal component of displacement for all nodes on the symmetry plane is fixed to be zero by selecting the associated curves.


b. General

c. Symmetry (Tx = 0 only)

d. 5 Curves; click OK

a

b

d

c

y y ( y)

• d. 5 Curves, OK


CHAPTER 154

Define ConstraintsThe horizontal and vertical displacement components of all nodes on the bottom of the block are fixed by selecting the associated curve.


b. General

c. Bottom (Tx, Ty = 0 only)

d. 1 Curve; click OK

a

b

d

c

c. Bottom (Tx, Ty 0 only)

• d. 1 Curve, OK

55CHAPTER 1


Define Point LoadThe load of 35 kN is applied to the top node in the downward direction. However, since only half of the material is being modeled because of the plane of symmetry, a load of 17.5 = 35/2 kN is applied to this “half” of the model.


b. Force

c. 1 Node

d. 17500, (direction); click OK

a

b

dc

• d. 17500, (direction), OK


CHAPTER 156

Create Nastran SOL 400 Job with Default LayoutAn analysis job is set up using a general nonlinear analysis type (SOL 400) and the name of the solver input file is specified.

a. Right click File Set

Create new Nastran job

b. Job Name

c. General Nonlinear Analysis (SOL 400)

d. Name input file; click OK

a

b

c

d

p

57CHAPTER 1


Create Nastran SOL 400 Job with Default LayoutThe global loadcase is created and the initial contact table is selected.

a. Right click Load Cases

b. Create Global Loadcase

OK

c. Under Global Loadcase, Right click Loads/Boundary Conditions

d. Select Contact Table BCTABLE_INIT; click OK

ab

c

d


CHAPTER 158

Select Contact Table BCTABLE_INIT for Loadcase DefaultLoadCaseThe default loadcase is created using the same contact table.

a. Right click Loads/Boundaries under DefaultLoadCase

b. Select Contact Table

c. Select Contact Table BCTABLE_INIT

d. Click OK

a

b

c

d

59CHAPTER 1


Define Large Disp. and Contact in SOL 400 Nonlinear ParametersHere, we are specifying some nonlinear parameters that allow forces to follow in a large displacement analysis and set the bias factor used in contact detection.

a. Double click Solver Control

b. Select Solution 400 Nonlinear Parameters

c. Large Disp and Follower Force, Apply

d. Contact Control Parameters

e. Bias = 0.90

f. click Apply

g. click Close

a

b

c

de

fg


CHAPTER 160

Define Nonlinear Static ParametersFinishing the selection of nonlinear parameters, we select the stiffness update method along with convergence criteria.

a. Loadcase Control

b. Subcase Nonlinear Static Parameters

c. Pure Full Newton, 1, 50

d. Check Displacement error, enter 1.0e-2

e. Check Force Error, enter 1.0e-2

f. Check Vector Component Method

a

bc

d

e

f

61CHAPTER 1


Request OutputIn order to visualize results, nodal and elemental output requests are made.

a. Output Request

b. Nodal Output Requests

c. Create Constraint Force output Request; click OK

d. Elemental Output

e. Create “Nonlinear” Stress Output,; click OK

a

b

c

d

e


CHAPTER 162

Run AnalysisThe preprocessing is now complete and the job is submitted. Upon successful completion of the job, the results are attached and visualized.

a. Right click job, cylinder_roller_contact, under Simulations

b. Run.

a

b

63CHAPTER 1


ResultsThe results are attached.

a. Attach Results

b. Select *_xdb file

a

b Select *.xdb file


CHAPTER 164

Results - Fringe PlotA fringe plot of the Y-component of the Cauchy stress tensor is plotted below.

a. Results

b. Fringe

c. Cauchy Stress

d. Y Component

e. Update

a

b

c

d

e

• b. Fringe

• c. Cauchy Stress

• d. Y Component• e. Update

65CHAPTER 1


Results - Chart DataSince the contact area is very small, it is useful to plot the Y component of Cauchy stress along the X component of the nodal positions, which is done by constructing the chart below.

a. Results

b. Chart

c. Stress, Y Comp., Nodes

d. Advanced Picking Tool

e. From Curve

f. Select Curve

g. X Global

h. Add Curves

b

c

g

f

d

e

a

h

a. Results

• b. Chart

• c. Stress, Y Comp., Nodes

• d. Advanced Picking Tool• e. From Curve

• f. Select Curve

• g. X Global• h. Add Curves


CHAPTER 166

Chart Data - Exporting Chart to ExcelUltimately, we wish to compare the data contained in the chart above with the analytical solution. The results in the chart can be extracted to the clipboard by selecting the Table under XY Chart Properties; then right click the table, Select All, and then copy. Once in the clipboard, the data can be pasted into Excel to be used in further comparisons.

a. XY Chart Properties, Check Table

b. Mouse on Table, Select All, Copy

c. Paste into Excel

a

b

c

67CHAPTER 1


Chart Data - Exporting Chart to ExcelThe chart data in the clipboard one pasted into Excel is then compared to the analytical solution.

a. Plot with Analytical Solution in Excel

a

Chart Data - Exporting Chart to Excel

• a. Plot with Analytical Solution in Excel


CHAPTER 168

Input File(s)Snippets from the first four Nastran input files listed below are used to illustrate the simulation throughout various sections of this chapter except the section, Pre- and Postprocess with SimXpert. This later section illustrates the simulation using the SimXpert workspace environment, instead of the Nastran input file(s). While both illustrations ultimately lead to the same solution, viewing the simulation from these two different viewpoints facilitates a better understanding of how to perform the simulation.

For example, nug_01am.dat, uses contact body IDs 5 and 6 as the set of elements for the block and cylinder, respectively; whereas the input file, ch01.bdf, (derived from the SimXpert workspace’s database, ch01.SimXpert) uses contact body IDs 1 and 2 as the set of elements for the block and cylinder, respectively. It is important to understand that while the contact bodies in these two input files are different (they use different IDs with a different set of elements), they yield the same solution since the loads, boundary conditions, and material properties are the same.

File Description

nug_01am.dat Linear Elements Without Friction

nug_01aw.dat Same as above but contact bodies are in wrong order

nug_01bm.dat Linear Elements With Friction

nug_01cm.dat Parabolic Elements Without Friction

nug_01dm.dat Parabolic Elements With Friction

ch01.SimXpert SimXpert Model

ch01.bdf Nastran input model (Linear Elements Without Friction)

http://www.mscsoftware.com/doc/nastran/mdug/input_files/ch001/nug_01am.dat

http://www.mscsoftware.com/doc/nastran/mdug/input_files/ch001/nug_01aw.dat

http://www.mscsoftware.com/doc/nastran/mdug/input_files/ch001/nug_01bm.dat

http://www.mscsoftware.com/doc/nastran/mdug/input_files/ch001/nug_01cm.dat

http://www.mscsoftware.com/doc/nastran/mdug/input_files/ch001/nug_01dm.dat

http://www.mscsoftware.com/doc/nastran/mdug/input_files/ch001/ch01.SimXpert

http://www.mscsoftware.com/doc/nastran/mdug/input_files/ch001/ch01.bdf

Documents

2-D Cylindrical Roller Contact