2D First Order Flexure Analysis with IDeas B. Privári Advanced Technology Center Lockheed Martin, Palo Alto Ca OPTI /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 default values Under Boundary Conditions module Simulation design

Define Restraint Set Clicking on ground icon again brings up this dialog box for ground constraints (six DOF) Click OK and then click on model feature to apply ground constraint

Load Condition Click on force icon to define magnitude and type of force, then click on model feature to apply force Vectors indicate applied forces and constraints

Create boundary set Combine the load set and ground constraint into a boundary set by selecting the icon: Under the management dialog box, select the create icon and insure that both the load set and restraint set are selected. Accept by clicking OK.

Creation of mesh elements Boundary Conditions Meshing Select icon in upper left corner and define element size and physical property then go to preview. (element length was set to 0.3 for this analysis)

Create/Confirm Element Selecting Change property brings up this dialog box that enables user to change thickness of element or edit directly from element definition icon. Recommend other options left at default values. Click OK when changes made (thickness was set to 10 mm for this analysis)

Confirm Mesh Set Selecting preview allows final adjustments to the mesh definition. once the mesh is defined, exit by clicking the Keep Mesh box.

Run Solution Meshing Model Solution Start by creating a Solution Set. This dialog box will display after the manage Solution Set icon is clicked Click OK and then click Solve under the other arrow icon in the menu

Output Selection Select the appropriate output parameters by clicking on the Output Selection button While defining Solution Set output options may be chosen prior to solving the model

View Results After Solve is Performed, Click on the Visualizer icon After invoking the visualizer several display options including a motion animation are available Displacement and stress are displayed 1 N force 2.94 micron displ 7.94 MPa stress

Stress at Flexure Joint Designer can query model to see where high stress condition exists and iterate after making modifications to solid model. Spring constant may be calculated from the applied force and output displacement, assuming conditions are below yield limit of 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