CADFamily.com: Small vs Large Deflection

9/21/2011

Workshop 2A: Large Deflection

Goal

Compare and contrast results using small deflection theory and large deflection theory on a model with identical loads and boundary conditions.

Model Description

– 3D Spring plate

– Linear steel material

– Meshed with 3D Solid elements

– Fixed support at one end, A

– 8 MPa Pressure load at opposite end, B

Steps to Follow:

Start an ANSYS Workbench session. Browse for and open “W2a_spring.wbpj” project file.

The project Schematic should look like the picture to the right.

– From this Schematic, you can see that the Engineering (material) Data and Geometry have already been defined (green check marks).

– It remains to set up and run the FE model in Mechanical

– Open the Engineering Data Cell (highlight and double click OR Right Mouse Button (RMB)>Edit) to verify the linear material properties.

– To see relevant dialog boxes, it might be necessary to go to Utility Menu > View..

Click on ‘Properties’ and ‘Outline’

– Verify that the units are in Metric(Tonne,mm,…) system. If not, fix this by clicking on…

Utility Menu > Units > Metric(Tonne, mm,…)

Return to Project Schematic

– Utility Menu > Return to Project

Double click on the Model Cell to open the FE Model (Mechanical Session) (or RMB=>Edit…)

Once inside the Mechanical application, verify the working unit system

– “Unit > Metric (mm,kg,N,s,mV,mA)”

The spring model is already set up with a fixed boundary condition and a pressure load on the opposite end.

– Highlight the Fixed Support and Pressure Load to confirm that the model is properly supported and loaded and ready to solve.

Note the Analysis Settings Specifications

– Auto Time Stepping = Program Controlled

– Large Deflection = Off

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