FEM of a sonotrode in Inventor 2014

[ich.mts]

Hi guys,

I have to simulate a sonotrode and find the best spots to tune it to a constant amplitude over its surface.

I already have the rough target geometry and I'm only looking for tuning-spots.

My idea was to make a modal-simulation which is integrated at inventor 2014 pro. but I don't get any usefull results.

The sonotrode is designed to have a frequency of 35kHz but inventor shows me a resonance freq. of about 38 kHz.

Of course it has many resonance-frequencies but I set the range of 34000 to 36000.

Anyway, is a modal-analysis the right method at all? Are the integrated functions of inventor enough for my purpose?

THX!

cu

[DonaldR.Culp7481]

Modal analysis is correct.

First check:

1. Are your boundary conditions correct? (Generally a full 3D model should not have any boundary conditions.)

2. Are your material properties correct? The frequency is mostly influenced by Young's modulus. If you are using titanium -

a. Titanium is orthotropic so the properties depend on the direction of vibration.

b. Handbook values for titanium's modulus are often incorrect.

If the above are correct then you may have to adjust a dimension (i.e., tune the sonotrode) to get the desired frequency.

If not proprietary, a jpeg and approximate dimensions of your proposed design would be helpful.

I don't have Inventor. However, I do extensive FEA of sonotrodes with Simulation Mechanical.

Don C.