2D First Order Flexure Analysis with IDeas

B. Privári

Advanced Technology Center

Lockheed Martin, Palo Alto Ca

OPTI 521

12/02/06

Overview

• Create model in IDeas Master Series• Reduce model into 2D planar entity• Convert from Design into Simulation

module• Create boundary conditions and load set• Apply mesh and material properties• Solve FEM• Review post-processing and results

Model Creation

• Example is flexure design to allow movement in xy plane only

• Model is created in version 12 of IDeas

• Analysis is done assuming no out of plane motion

• Material analyzed is Titanium

• 2D analysis allows quicker iterations of design before detailed study is performed

Ideas geometry in three and two dimensional form

Reduce 3D model

• Ancillary model is created and reduced– Perform a move/copy command on orig. part– Original part is preserved – Analyze ancillary part

• Unnecessary features are deleted

• Remaining geometry is planar element

Start FE Model

Create FE model

Accept defaultvalues

Under BoundaryConditions module

Simulation

design

Define Restraint Set

Clicking on groundicon again brings up this dialog box forground constraints(six DOF)

Click OK and thenclick on model featureto apply ground constraint

Load Condition

Click on force iconto define magnitude and type of force,then click on model feature to apply force

Vectors indicate applied forcesand constraints

Create boundary set

Combine the load setand ground constraintinto a boundary set byselecting the icon:

Under the managementdialog box, select thecreate icon and insurethat both the load set and restraint set are selected. Accept by clicking OK.

Creation of mesh elements

Boundary Conditions

Meshing

Select icon in upper leftcorner and define elementsize and physical propertythen go to preview.

(element length was setto 0.3 for this analysis)

Create/Confirm Element

Selecting Changeproperty brings upthis dialog box thatenables user tochange thicknessof element or editdirectly from elementdefinition icon.Recommend otheroptions left at default values.

Click OK whenchanges made

(thickness was setto 10 mm for thisanalysis)

Confirm Mesh Set

Selecting previewallows final adjustments to themesh definition.once the mesh isdefined, exit byclicking the KeepMesh box.

Run SolutionMeshing

Model Solution

Start by creating a SolutionSet. This dialog boxwill display after the manageSolution Set icon is clicked

Click OK and then clickSolve under the otherarrow icon in the menu

Output Selection

Select the appropriateoutput parameters byclicking on the OutputSelection button

While defining Solution Setoutput options may be chosen prior to solving the model

View ResultsAfter Solve isPerformed, Click on the Visualizer icon

After invokingthe visualizerseveral displayoptions includinga motionanimation areavailable

Displacementand stress aredisplayed

1 N force2.94 micron displ7.94 MPa stress

Stress at Flexure Joint

Designer can query model to seewhere high stresscondition exists anditerate after makingmodifications to solidmodel.

Spring constant maybe calculated fromthe applied force andoutput displacement,assuming conditionsare below yield limitof material.

Review Results

• Display stresses and displacements• Confirm that design is acceptable or

determine locations or model requiring modification.

• Re-run model with alternate load conditions, if necessary.

• Provides quick & easy insight for designer on how to converge to an acceptable flexure design solution using IDeas

Acknowledgement

Special thanks to Buck Holmes of the LMATC who first stepped author through this process