Operational Deflection Shapes ODS

Hey all!

I'd like to enhance the investigation of the resonances of a mechanical system model incluing flexibles structures. Is it possible to extract operational deflection shapes from the System after the simulation using the Adams PPT? Or should I stop the Simulation at a certain time step(system state) and do a linear mode analysis?

What are your thoughts on this?

Kind Regards

Nils

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0 nils_s over 7 years ago
So my model is running properly right now, usin the following steps.

preload the model using applied forces and global constraints at the system boundary in a dynamic simulation step

replace constraints by applied forces to regain the DOFs of the system

run a static simulation

linearize the model about the static equilibrium

First the linearized model did not show the resonance frequencies that I see in the dynamic simulation in steady state condition, so I had a look at the documentation to find out what could have gone wrong.

I came over the RM option of the LINEAR/EIGENSOL command and what I found out is that there is a significant dependency of the calculated eigenfrequencies to the reference marker you chose for the linearization of the model equations. In my case I did not even chose a reference marker on a moving part. I just used one ground marker which is at the force interface where the resonance frequency showed... Now I am struggling to understand the difference

Do you have experience in doing this? What are your lessons learned?

Kind Regards

Nils
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0 nils_s over 7 years ago
So my model is running properly right now, usin the following steps.

preload the model using applied forces and global constraints at the system boundary in a dynamic simulation step

replace constraints by applied forces to regain the DOFs of the system

run a static simulation

linearize the model about the static equilibrium

First the linearized model did not show the resonance frequencies that I see in the dynamic simulation in steady state condition, so I had a look at the documentation to find out what could have gone wrong.

I came over the RM option of the LINEAR/EIGENSOL command and what I found out is that there is a significant dependency of the calculated eigenfrequencies to the reference marker you chose for the linearization of the model equations. In my case I did not even chose a reference marker on a moving part. I just used one ground marker which is at the force interface where the resonance frequency showed... Now I am struggling to understand the difference

Do you have experience in doing this? What are your lessons learned?

Kind Regards

Nils
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