Stiffness estimation

[maheshh]

All

I need inputs on setting up a model (static structural) if I want to estimate the stiffness of a support component in an assembly.

The assembly is complex, but the support component is a fairly straightforward stamped steel structure. How do you recommend setting up the model to compute the effective stiffness of the component?

Thanks in advance.

 

[gurmeet2003]

mahesh,

In order to find the stiffness of one particular component, fix a part of the component (surface, edge etc.) and apply a load to another part of the structure. Run the model and find out the deflection. Divide the load by deflection. This should give you the stiffness you need.

How to figure out where to fix the part, and where to apply the load? How much load should be applied? For answer to these questions you will have to study your assembly.

Gurmeet

 

[maheshh]

That is understood. But if the load is area load, how can I do a load/deflection plot?

 

[cbrn]

Hi,
maheshh, I'm probably missing something, so excuse me in advance if I don't really see your point.
A load is a load, it doesn't matter if it's a surface distributed load or a concentrated force load. The integral of the pressure over the surface is the total resultant force applied.
In other terms: if you want to determinate the stiffnesses of the component, theoretically you have to determine 21 coefficients (6x6 matrix, symmetric). But you can restrict your search only to the DOFs of interest. In this case, think about a sensable restraint schema and apply a "generalized force" acting coherently. You don't have to bother neither about force magnitude, neither about "force / deflection" diagram, if you work under linear hypothesis. It's only if you are searching for the non-linear stiffness that you have to retrieve the force / deflection diagram. As for how to retrieve the force magnitude when applying a distributed load, you have plenty of tools: *GET function on reaction forces, FSUM, FORCE, NFORCE.

Regards