meshing and analysing of a shaft...introduction to altair hypermesh tm and altair hyperview :...
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Marius Müller
Introduction to Altair HyperMeshTM
and
Altair HyperViewTM
:
Meshing and analysing of a shaft
©October 2018 by Marius Müller
Graz, October 2018
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 1
Meshing and analysing of a shaft
1. Creation of geometry 1.1.Click F8 and choose XYZ
1.2.Create a node at (0/0/0)
a. Create a node at (0/0/30)
1.3.Create a node at (100/0/30)
1.4.Create a node at (100/0/20)
1.5.Create a node at (100/0/0)
1.6.Create a node at (200/0/0)
1.7.Create a node at (200/0/20)
1.8.Combine the nodes with lines
i. Create a component for the lines and choose a colour
Right click on the model tree => create => Component
ii. Go to the Geometry panel and choose lines
iii. Choose linear nodes
iv. Create lines
Figure 2: Lines connected to nodes
Geometry scale: 1:2
200
Ø4
0
Ø6
0
Geometry scale: 1:2
100
Evaluation plane
92
Figure 1: Geometry of shaft
F = 500 N
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 2
1.9.Creation of surfaces
v. Create a component for the surfaces and choose a colour
vi. Go to the Geometry panel and choose surfaces
vii. Choose Spline/Filler
viii. Change “Create in:” into “Current Component”. This way the surface will be created in the current component
1.10. For creating the radius you again need a surface
ix. Create a node at (110/0/30) and draw a circle with a radius of 10 mm
x. Go to the Geometry panel and click on surfaces and choose
Spline/Filler and create a surface out of the lines
xi. Geometry panel => surface edit => trim with surface/plane => choose
the surface you want to trim and select the node where you want to trim
the surface.
xii. Trim the circle with the x-axis and the z-axis and delete the not needed
surfaces and lines
1.11. Go again to the Geometry panel and click on surfaces
xiii. Choose spin and click on one of the lines you want to spin and set the
x-axis as the rotational axis and select a node to spin around
1.12. Now click on Spline/Filler in the Geometry panel and close the open body
1.13. Then go to solids in the Geometry panel and choose Bounding Surfaces
Figure 3: Surfaces generated
Geometry scale: 1:2
Figure 4: Quarter circle generated
Geometry scale: 1:2
Figure 5: Solid generated
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 3
1.14. Delete all of the nodes: Click Shift + F2 => clear all
1.15. Delete the old surfaces: Right click on the component => Delete
2. Creation of assemblies and preparation for the mesh 2.1.Click into the model tree with the right mouse button and create the following
assemblies:
i. CAD
ii. Surfaces
iii. FEM
iv. Mesh_2D
2.2.Create the following components
i. CAD_notched_shaft
ii. Copy_notched_shaft
iii. Surf_ notched_shaft
iv. Shell_ notched_shaft
v. Hex_ notched_shaft
2.3.Move the components into the right assembly
2.4.Turn your solid shaft into the component CAD_notched_shaft
i. Go to the Tool panel and click on organise
ii. Select solids and choose the shaft and then select move
2.5.Make a copy of your shaft
i. Right click on Copy_notched_shaft => Make Current
Figure 6: Creation of assemblies
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 4
ii. Go to the Tool panel and click on organise
iii. Select solids and choose the shaft and then select copy
2.6.Cut the “Copy_nothed_shaft” into one quarter i. Only display the component “Copy_nothed_shaft”
1. Right click on the component => Isolate only
ii. Create a node on the rotation axis of the shaft:
Click F8, go to Arc center and select lines
Click on one of the circles at the beginning or the end of the
shaft and click create
iii. Go to the Geometry panel and select surface edit and click on “trim with surfs/planes, select the z-axis and the node you created before
iv. Do the same for the y-axis
v. Delete the not needed solids
Click F2 and select solids and make sure to click on “delete bounding surfs. This way you also delete the bounding surfaces
of your solid
2.7.Create a surface where you can model on
i. Make the component “SURF_notched_shaft” current ii. Go to the Tool panel and click on organise and copy the surface (the
surface in the zx-plane) of the quarter shaft
iii. Hide the solid
Surface we will model on
Figure 7: Quarter shaft
Figure 8: Surface of the notched shaft in the zx-plane
Geometry scale: 1:2
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 5
3. Meshing of the notched shaft In order to get good results in the analysis, it is necessary to generate an appropriate
mesh. Areas where high stress gradients are expected should be modelled with a fine
mesh, areas where the expected stress gradient is not that high can be modelled with
coarser elements.
3.1.Preparation of the surface in order to generate a good mesh on it
3.2.Hiding everything beside “Surf_notched_shaft”
3.3.Cutting the geometry in order to achieve a good element quality and a fine
mesh in the area of the notch
i. Use the Geometry panel and the surface edit function to cut the surface in
a way as shown in Figure 9.
ii. The surface must be cut in the z direction above the axis of rotation (x-
axis) of the shaft in order to avoid penta elements
iii. Make sure that you have a point in the area of the evaluation plane!!!
We want to evaluate the stresses there.
3.4.Mesh the prepared surface with first order QUAD elements
i. Set the component “Shell_notched_shaft” to current ii. Press F12, select surfs and set the element size to 3 mm
iii. Make sure that “elems to current component”, “first order” and “keep connectivity are active
Geometry scale: 2:1
Figure 10: Mesh panel
Figure 9: Cut surface
Geometry scale: 1:2
Evaluation plane
92
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 6
iv. Click on the surface you want to mesh
3.5.Spin the generated 2D mesh in order to create 3D Hex elements
i. Make the component “Hex_notched_shaft” active
ii. Go to the 3D panel
iii. Click on spin
iv. Click on spin elems
v. Select the 2D elements and select an axis of rotation (x-axis) and the point
you want to spin the elements around
vi. Set the angle to 360°
vii. on spin = 36
Figure 11: Created 2D mesh
Geometry scale: 1:2
Geometry scale: 2:1
Figure 12: 3D elements created with the spin function
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 7
In order to close the hole in the middle of the shaft, we again have to create a surface.
We will create a 2D mesh on that surface and drag it along the nodes of the recently
created 3D elements.
3.6.Generate 2D elements on this surface.
3.7.Go to the 3D panel and click on solid map
i. Choose “along geom => node path” and “elems to drag” and hide all other options in this panel
ii. Mark the elements you want to drag
iii. Choose a node path and click mesh
Figure 13: 3D elements created with the spin function and surface added
Surface
Figure 14: 2D elements ready to drag
Geometry scale: 1:1
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 8
3.8.The mesh will be automatically created in a new component called solidmap
i. Convert these elements into the component “hex_notched_shaft”
Figure 15: Usage of the Solid Map function
Node path Selected elements
Figure 16: Shaft modelled with first order hex-elements
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 9
3.9.Do a quick check if all elements are connected
i. Just display the component “hex_notched_shaft”
ii. Create the faces of these solid elements
iii. Hide the solid elements
iv. Check if you have any edges remaining
v. Delete parts of the faces-elements and check if there are faces-elements
remaining in the inner part of your model
vi.
4. Creating materials and properties In order to calculate you have to define materials and properties to your model.
4.1.Create a material
i. Right click on the model tree
ii. Select Create and Material
iii. Give the material a name: “mat_steel”
iv. Type in the density, the E-Modulus and the Poisson’s ratio
v. MAT1 – isotropic, temperature independent material
Create faces Check for edges
Figure 17: Checking the elements
Figure 18: Material definition
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 10
4.2.Create a property
i. Right click on the model tree
ii. Select Create and Property
iii. Give the material a name: “prop_shaft”
iv. Choose PSOLID
v. Set the material to mat_steel
vi. Assign the property to the component “hex_notched_shaft”
5. Create a coupling element to distribute the force at the end of the
shaft
5.1.Create a new component: “rbe3_force”
5.2.Create a node in the middle of the end of the shaft
Figure 19: Property definition
Figure 20: Creating node for coupling element
Node
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 11
5.3.Go to the 1D-panal and click on rbe3
5.4.Change dependent from “calculate node” to “node”
5.5.Click on the node you created before
5.6.For the independent nodes choose all nodes of the circumference
6. Create a force acting on the dependent point of the coupling element 6.1.Right click on the model tree => Create => Load Collector
i. Name the load collector: LC_force
ii. Make sure that LC_force is active
6.2.Go to the Analysis panel
6.3.Click on forces and click on create
6.4.Type in the magnitude: 500 Newton
6.5.Choose the global z-axis as definition for the direction of the force
6.6.Load types = FORCE
6.7.Click on the dependent point of the rbe3
6.8.Click on create
Figure 21: Creating coupling element
Figure 22: Created coupling element (rbe3)
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 12
7. Create boundary conditions 7.1.Right click on the model tree => Create => Load Collector
i. Name the load collector: BC
ii. Make sure that BC is active
7.2.Go to the Analysis panel
7.3.Click on constraints
7.4.Choose all nodes at the beginning of the shaft
7.5.Set DOF1 to DOF6 to 0.0
Figure 23: Creating constraints
Figure 24: Boundary conditions and force created
Geometry scale: 1:2
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 13
8. Create a Load Step 8.1.Right click on the model tree => Create => Load Step
8.2.Analysis type: Linear static
8.3.SPC => BC
8.4.Load => LC_force
8.5.Subcase options:
i. Output:
Displacement
SPCF
Strain
Stress
In order to not create very large files during calculation, you can select from different
outputs requests which you want to have a look on later in the Post-Processing.
9. Export the model to run the calculation 9.1.Delete every component beside the components in the assembly FEM
(hex_notched_shaft; rbe3_force)
9.2.Save the model as a copy
9.3.Click on Export Solver Deck
10. Open OptistructTM
and run the calculation 10.1. Open Optistruct
TM
10.2. Read in your model (model.fem)
10.3. Click on run and wait
Export Solver Deck Figure 25: Export Solver Deck
Figure 26: Open OptistructTM
and run the calculation
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 14
11. Open HyperViewTM
and view the results 11.1. Open HyperView
TM
11.2. View the deformation / displacement
11.3. View Stresses – vonMises strsses and advanced averaging method
11.4. Create appropriate legend
11.5. Display the major stresses (P1)
11.6. Display the minor stresses (P3)
Figure 27: Legend for stresses
Figure 27: vonMises stresses
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 15
Figure 28: Major stresses
Figure 29: Minor stresses
Introduction to Altair HyperMeshTM and Altair HyperViewTM: Meshing and analysing of a shaft
©October 2018 by Marius Müller Page 16
12. Compare the results with an analytical solution
Bending moment: 𝑀𝑏𝑦 = 𝐹 ∗ 92 = 500 ∗ 92 = 46 𝑁𝑚 (1)
Moment of resistance: 𝑊𝑦𝑦 = 𝑑3 ∗ 𝜋 ∗ 132 = 6521.8 𝑚𝑚3 (2)
Bending stress: 𝜎𝑦𝑦 = 𝑀𝑏𝑦𝑊𝑦𝑦 = 7.05 𝑀𝑃𝑎 (3)
Shear force: 𝐹𝑄𝑧 = 500 𝑁 (4)
Shear stress: 𝜏𝑞 = 4∗𝐹3∗𝐴 = 0.517 𝑀𝑃𝑎 (5)
vonMises: 𝜎𝑉,𝑀 = √𝜎𝑦𝑦2 + 3 ∗ 𝜏𝑞2 = 𝟕. 𝟏𝟏 𝑴𝑷𝒂 (6)
Have a lot of fun learning how to use HypermeshTM
and HyperViewTM
!!!
Ø4
0
Geometry scale: 1:2
Evaluation plane
92
Figure 30: Shaft – Internal forces at evaluation plane
F = 500 N
FQz
Mb
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