In this chapter using HyperMesh
? Import ABAQUS input (INP) files
? Create ABAQUS systems *SYSTEM, *ORIENTATION and *TRANSFORM
? Define ABAQUS non-linear material
? Create *CLOAD on nodes in *TRANSFORM
? Complete partially defined *STEP
Hands-on exercises in this chapter encompass setting up an analysis for the non-linear static response of a half disc to forces on it. Creating the ABAQUS input file for this analysis using HyperMesh is broken down into two sections:
Complete the model data
Import ABAQUS INP file containing some model and history data
Update the existing *MATERIAL with non-linear attributes
Create *TRANSFORM
Complete the history data
Specify analysis procedure for the existing, partially defined *STEP
Apply *CLOADs on nodes in *TRANSFORM
Add output requests to existing *STEP
Comments: Units used in this model are as follows:
Length
Millimeters (mm)
Force
Kilonewtons (kN)
Mass
Megagrams (Mg)
Section 1: Complete the model definition
Overview for importing INP files into HyperMesh
Follow these guidelines when importing ABAQUS INP files into HyperMesh:
· The ABAQUS import translator supports free and fixed formats. However, the HyperMesh ABAQUS templates write all cards in free format as required by ABAQUS 6.2.1.
· If you import an ABAQUS 5.8 file, the input translator will covert all the cards to ABAQUS 6.2.1 format.
· HyperMesh organizes all elements into separate component collectors, based on sectional property.
· Loads in the model definition are organized into HyperMesh load collectors with the card image INITIAL_CONDITION.
· A *STEP is organized into a HyperMesh load step.
· Loads and constraints in a *STEP are organized into HyperMesh load collectors with the card image HISTORY. These load collectors are organized into the corresponding load step.
· Output requests in a *STEP are organized into a HyperMesh output block. The output block is organized into the corresponding load step.
· Warnings and error messages are written to a file named abaqus.msg. Unrecognized lines are written to a *.hmx file. These files are created in the same directory from where HyperMesh is launched.
· HyperMesh does not support *PART and *INSTANCE in INP files (from ABAQUS/CAE).
Exercise 1.1: Import ABAQUS INP file
Import an ABAQUS INP file containing the following model and history data:
· One ELSET named disc with a *SOLID SECTION property
· Elements of type C3D20 (2nd order) belonging to the ELSET disc
· *MATERIAL named Aluminum associated to the ELSET disc
· One *STEP named step1 containing *BOUNDARY and output requests
1. Press F2 to enter the delete panel in the Tool page.
2. Click delete model to delete the model from the HyperMesh session.
3. Click return to go to the main menu.
4. Enter the files panel.
5. Select the import sub-panel.
Notice the FE radio button is active and next to the switch is ABAQUS. This means the ABAQUS import translator is selected. It was automatically selected when you loaded the ABAQUS user profile.
6. Click import… and select HalfDisc_Start.inp.
7. Click Open.
8. Click return.
Exercise 1.2: Create *PLASTIC for *MATERIAL
A *MATERIAL named Aluminum exists in the model. Update it by specifying non-linear attributes; add the keyword *PLASTIC and data lines for *PLASTIC. The *ELASTIC keyword is already specified in the *MATERIAL definition. *ELASTIC is required when *PLASTIC is present.
1. Enter the collectors panel and select the card image sub-panel.
2. Select mats for the collector type.
3. Click name = and select Aluminum.
Notice when you selected Aluminum, the card image = field was automatically populated with ABAQUS_MATERIAL. This is an indication the ABAQUS_MATERIAL card image is already loaded for the Aluminum material collector.
4. Click edit.
5. Activate Plastic.
6. Click the switch under Hardening and select ISOTROPIC
7. Enter 3 in the data entry field for PLASTICDATACARDS.
8. In the pop-up card image, enter the following numbers into the appropriate data entry fields under YieldStress and PlasticStrain.
YieldStress
PlasticStrain
410 Mpa
0.0
430 Mpa
5.70 E-3
450 Mpa
6.00 E-3
9. Click return twice to return to the main menu.
Definition of the *MATERIAL is complete.
Overview of ABAQUS systems in HM
*SYSTEM specifies a local system defining node coordinates. Define this system in HyperMesh as follows:
1. Using the collectors panel, create a systems collector.
2. From the Geom page, use the systems panel to create a HM system.
3. In the systems panel, assign sub-panel, use the set reference function to assign nodes to the system. The system is now a *SYSTEM for the assigned nodes.
A card image for *SYSTEM is not available for review in HM. However, you can see the nodes assigned to a *SYSTEM by using the review functionality in the systems panel. On export to the ABAQUS input file, a *SYSTEM card is followed by the nodes defined in it.
*TRANSFORM specifies a local system defining the directions for the degrees of freedom of nodes. Define this system in HyperMesh as follows:
1. Using the collectors panel, create a systems collector.
2. From the Geom page use the systems panel to create a HM system.
3. In the systems panel, assign sub-panel, use the set analysis function to assign nodes to the system. The system is now a *TRANSFORM for the assigned nodes.
A card image for *TRANSFORM is not available for review in HM. However, you can see the nodes assigned to a *TRANSFORM by using the review functionality in the systems panel. On export to the ABAQUS input file, a *TRANSFORM references the automatically generated *NSET. The *NSET is followed by a list of nodes assigned to the *TRANSFORM. When the ABAQUS input file is imported into HM, the NSET, including its name, is read and maintained on export.
*ORIENTATION is discussed in detail in Chapter 4 where you create one.
All three ABAQUS system types can be created from a single HyperMesh system. However, it is suggested you create only one ABAQUS system from a HyperMesh system. This allows you to better organize the systems. Also, when an ABAQUS input file is imported into HyperMesh, a system is created for each ABAQUS system and each system is organized into its own systems collector.
Remove nodes from a *SYSTEM or *TRANSFORM by assigning them to another system using set reference or set analysis, respectively.
http://www.cadfamily.com/html/Article/Pre-processing%20for%20Half%20Disc%20Analysis_959_1.htm
http://www.cadfamily.com/html/Article/Pre-processing%20for%20Half%20Disc%20Analysis_959_2.htm
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