radioss接触非线性分析

HyperWorks Solvers
The purpose of this tutorial is to demonstrate how to carry out nonlinear implicit small displacement analysis in OptiStruct, involving elasto-plastic materials, contact and continuing the nonlinear solution sequence from a preceding nonlinear loadcase.
Model and Loading Description
Figure 1 illustrates the structural model used for this tutorial: Two square solid blocks made of elasto-plastic steel material. The dimensions of the blocks and the material parameters can be obtained in the table below.
In the first nonlinear subcase, pressure loading is be applied to the top solid block, the top corners of which are constrained in X and Y directions. The top solid is in contact with the bottom solid, the bottom corners of which are constrained in X, Y and Z directions. The second nonlinear subcase is
to simulate the un-loading and is a continuation of the nonlinear solution sequence from the previous loading subcase.
Figure 1. Model and Loading Description
Units Length: mm; Time: s; Mass: Mgg; (Force: N; Stress: MPa)
Top block72 mm x 72 mm
Bottom block100 mm x 100 mm
Thickness of
20. mm
blocks
Material Steel, Elasto-plastic
Initial density ():7.90e-9 kg/mm3
Young's modulus (E):210000 MPa
Poisson coefficient (ν):0.3
Yield Stress (0):850.0 MPa
Imposed pressure1000.0 MPa, applied at the center of top block
The following exercises are included in this tutorial:
•Create elasto-plastic material
•Define contact between the two blocks
•Define nonlinear implicit parameters
•Set up NLSTAT analysis for the 1st subcase (loading)
•Set up NLSTAT analysis for the 2nd subcase (unloading)
•Submit job and view result
Exercise
Step 1: Import the model
unch HyperMesh.
2. A User Profiles Graphic User Interface (GUI) will appear, select OptiStruct.
3.Click OK. This loads the User Profile.
4.Click File>Open.
Note:If HyperMesh Desktop was launched, use:File > Open >
Model.
5.Select the file nlstat.hm located in the HyperWorks installation directory under
<install_directory>/tutorials/hwsolvers/optistruct/.
6.Click Open.
Step 2: Create the elasto-plastic material
First, the stress vs plastic strain curve for the material needs to be defined.
1.In the Tab area, click on the Utility menu. If not active, click View > Utility.
2.Click on the TABLE Create tool.
3.Click on Create/Edit Table and select the table type as TABLES1.
4.Click Next.
5.Click the radio button for Create New Table and enter the Name of the table as stress-
strain.
6.Next, populate the X and Y fields of the table, as shown below.
7.Click Apply.
A dialog box will appear stating: 'The load collector “stress-strain”with TABLES1 card image is
cr e ated’.
8.Click OK to close the dialog box.
Now, the elasto-plastic material needs to be updated.
9.In the toolbar, click the Material icon .
10.Toggle the Update subpanel.
11.Click on mats and select the material steel.
12.Click update/edit.
13.Click on MATS1 to define the elastic-plastic material for NLSTAT analysis.
14.Click TID and select stress-strain.
15.Input the values, as shown below. [TYPSTRN] of 1 signifies specifying stress (Y) vs plastic
strain (X).
See material parameters for details.
16.Click return twice to go to the main menu.
Step 3: Define contact between the two blocks
The contact surfaces for the two blocks need to be defined.
1.In the Analysis page, click on entity sets panel.
2.For name=, enter top.
3.Set card image to SET_ELEM.
4.Toggle entity and select props.
5.Click on props and select the top solid Solid1.
6.Click create.
7.Next, for name=, enter bottom.
8.Repeat steps 3 through 6, for bottom block select the bottom solid Solid2.
9.Click return to go to the main menu.
Next, the interface needs to be defined.
10.Click on interfaces panel with the toggle set to create.
11.For name =, enter solid_contact.
12.For type =, select CONTACT, then click create.
13.Next, click the radio button for add to add the master and slave surfaces to the interface
definition, as shown below.
14.Toggle master: to sets and select bottom.
15.Click update.
16.Toggle slave: to sets and select top.
17.Click update.
18.Click review to review the interface, as shown in Figure 2.
Figure 2. Slave and master surface definition
19.Click on card image and then click edit to specify the contact definition, as shown below.
20.Click return twice to return to the main menu.
Step 4: Define nonlinear implicit parameters
1.In the toolbar, click on Load Collectors icon .
2.Toggle create and for loadcol name =, enter nlparm.
3.Toggle card image =, and select NLPARM.
4.Click create/edit and specify the defaults, as shown below.
See nonlinear implicit parameters for details.
5.Click return twice to go to the main menu.
Step 5: Create the 1st nonlinear (loading) subcase
1.Click on the loadsteps panel.
2.For name =, enter loading.
3.Toggle type: to non-linear quasi-static.
4.Check the box preceding SPC. An entry field appears to the right of SPC.
5.Click on the entry field and select the SPC load collector.
6.Check the box preceding LOAD. An entry field appears to the right of LOAD.
7.Click on the entry field and select the pressure load collector.
8.Check the box preceding NLPARM. An entry field appears to the right of NLPARM.
9.Click on the entry field and select the nlparm load collector.
10.Click create.
Step 6: Create the 2nd nonlinear (unloading) subcase
1.For name =, enter unload.
2.Uncheck the box preceding LOAD.
3.Keep the boxes preceding SPC and NLPARM checked, as shown below.
4.Click create.
5.Click edit and select CNTNLSUB to continue the solution sequence from the previous loading
subcase.
6.Click return twice to go to the main menu.
Step 7: Define Output Control parameters
1.From the Analysis page, select control cards.
2.Click on GLOBAL_OUTPUT_REQUEST.
3.Under CONTF, DISPLACEMENT, STRAIN and STRESS, set Option to Yes.
4.Under STRAIN, set TYPE(1) to PLASTIC.
5.Click return twice to go to the main menu.
Step 8: Submit the job
1.From the Analysis page, select OptiStruct.
2.Click save as and select the directory where you want to write the file.
3.For File Name, enter nlstat_complete.fem.
4.Click Save. The file extension .fem is necessary for OptiStruct to recognize it as an input file.
5.Set the export options toggle to all.
6.Set the run options toggle to analysis.
7.Set the memory options toggle to memory default.
8.Click OptiStruct. This launches the OptiStruct job.
If the job is successful, you should see new results files in the directory where HyperMesh was invoked. The nlstat_complete.out file is where you will find error messages that will help you debug your input deck, if any errors are present.
The default files that will be written to your directory are:
nlstat_complete.html HTML report of the analysis, giving a summary of the
problem formulation and the analysis results.
nlstat_complete.out ASCII based output file of the model check run before the
simulation begins and gives nonlinear iteration history as well
as basic information on the results of the run.
nlstat_complete.stat Summary of analysis process, providing CPU information for
each step during the process.
nlstat_complete.h3d HyperView compressed binary results file.
Step 9: View analysis results
ing HyperView, plot the Displacement, the von Mises stress, plastic strains and contact
pressure contours at the end of the 1st (loading) step.
Figure 3. Contour of Displacements in blocks subject to Loading
Figure 4. Contour of von Mises Stress in blocks subject to Loading
Figure 5. Contour of Plastic Strains in the blocks subject to Loading
Figure 6. Contour of Contact Pressure in the block interface after the 1st (loading) subcase
Next, change the subcase to the 2nd that is unloading subcase and plot the displacement contour to see the change in displacements in the blocks subject to unloading.
Figure 7. Contour of Displacements in blocks subject to Unloading in 2nd subcase
See Also:
OptiStruct Tutorials。