Modal FRF optimization technique to shift first frequency or reduce the FRF stress

VIGNESH_P

Hi team,

I have done a Modal FRF for a bracket and the operating frequency is between 0 to 2000Hz. The first resonance frequency is at 1063Hz and the stress at that frequency is 800MPa. I need to do an optimization either to shift the first frequency from 1063 Hz to more than 2000 Hz or need to reduce the stress generated (800 MPa) below 200 MPa.

I need your help to choose which optimization technique is best for this kind of analysis?

I have tried topology optimization to increase the first frequency of modal analysis, topology optimization to reduce the FRF stress by Volume fraction as constrain. But design is infeasible.

Also I have tried shape optimization to reduce the FRF Stress, but the stress reduced was only 10MPa from the original value. Here the design is feasible and all constrains were satisfied.

I need your help to carry out this optimization analysis either by reducing the stress or shift the 1st resonance frequency above 2000Hz.

Thanks in advance.

Garima_Singh

Hi @VIGNESH_P,

From the description provided, it is clear that either the design variables (shapes) or their multiplier values are not enough to achieve the design targets.

Hence, it is suggested that firstly the design variables are thoroughly identified & then, their admissible lower & upper bounds are determined.

In such cases where it is not clear if the design variables are correctly selected or their bounds are enough to provide an optimal design, HyperStudy can be a good starting point to check if any feasible or optimal design exists in the design space.

• One can first perform a DOE (Design of Experiments) to understand how shapes as design variables with the defined bounds are contributing/affecting to the design targets.
• Based on the DOE results provided, one can then think of either modifying the shapes bounds or adding more/new design variables based on the domain knowledge.

To get started with HyperStudy, one can refer the HyperStudy e-learning with examples to learn & understand the same.

https://learn.altair.com/courses/getting-started-with-hyperstudy-elearning

Many thanks.

Kind Regards

Garima Singh

Engineering Data Science