Learning Forum

[joseph.moss]

Hi all,

I am currently creating a parametric tool on Workbench/Mechanical. For one of the parameters, I want its value to change based on the material selection of the body in the analysis. The material selection occurs by selecting the name of the material from a drop down menu. Here is the expression I am currently using:

-32.17117004 if P10 == "Titanium Alloy 15-3-3-3" else -47.87632636 if P10 == "Ti-64" else -43.21143658

This expression works, however it defaults to -43.21143658, as I don't think the strings I have input are recognised.

If I select the material to be Ti-64, and then use the expression P10 == "Ti-64" it returns as false.

This makes me think I am not referencing the selections from the drop-down menu properly. Does anyone know how to do this? Thanks

[Jason Logan]

 

Hi, Just to follow up as I’m working with Joe on this; and he's found a way around it (sort of).

To clarify we believe this issue is completely to do with trying to select from a dropdown menu; it just doesn’t recognise it as text. Since if I were to create a new parameter and put in the expression: P1, it returns this warning error:

There were ways around this error:

 

• Either by using parameters we knew would change with each material type; i.e. mass of structure. And build the IF expression around that.
• Or, instead of a dropdown menu, assigning a new Master parameter with a value 1, 2, 3, etc and a master material entry with IF expressions for each material input (density/E/Poisson ratio), and other parameters that would change based on the Master parameter value. 

[Tasos Zacharakis]

Hello Joe and Jason,

 

The Workbench syntax rules for the parameters are described at : Expressions, Functions, Quantities, and Units. I understand it needs a numeric value within the expression to work.

 

Thank you,

Tasos