Maximize the first resonance frequency of a plate.
Maximize the first resonance frequency of a plate.
(OP)
Hi
I have a plate made of a certain material (plastic, cannot be changed). I need to maximize the first resonance frequency of the plate. The availible methods are: making some places thinner and using ribs.
When using ribs on the plate with fixed dimensions (100mm x 75mm x 2mm) you can't increase the net weight of the plate with more than 10 percent.
Is there somebody with experience with such problems? What is according to you the best way to increase the first resonance frequency to the maximum.
Thanks in advance!
Kindest regards,
Vidi
I have a plate made of a certain material (plastic, cannot be changed). I need to maximize the first resonance frequency of the plate. The availible methods are: making some places thinner and using ribs.
When using ribs on the plate with fixed dimensions (100mm x 75mm x 2mm) you can't increase the net weight of the plate with more than 10 percent.
Is there somebody with experience with such problems? What is according to you the best way to increase the first resonance frequency to the maximum.
Thanks in advance!
Kindest regards,
Vidi





RE: Maximize the first resonance frequency of a plate.
2. What are the boundary conditions?
3. Is this a project for school?
RE: Maximize the first resonance frequency of a plate.
The answer will change depending on your boundary conditions.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Maximize the first resonance frequency of a plate.
floattubber: Its the frequency, not response, that needs to be maximized. Why? The plate is used in a design where it operates at certain frequencies where it must not resonate. So the idea was to use techniques to maximize the first eigen frequency.
Thanks for help!
Regards,
Vidi
RE: Maximize the first resonance frequency of a plate.
Are you expecting to solve this analytically, or by FEA?
Do you have a maximum section depth, or is that effectively controlled by the 'no more than 10% mass increase' and 'walls must be at least 2mm thick' requirements?
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Maximize the first resonance frequency of a plate.
What do you mean by that- how thin can you go across the main face of the part?
What do you get as your first mode (frequency, mode shape)?
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Maximize the first resonance frequency of a plate.
The depth dimension is not a constant, but it must respect the mass constraint and the minimum 2mm constraint.
The first mode: http://files.engineering.com/getfile.aspx?folder=81073892-0af3-4a9a-80f7-0e8214bcc7d4&file=a.avi
The problem is being solved using FEM.
Thanks alot!
RE: Maximize the first resonance frequency of a plate.
Ribs are generally rather useless for torsion.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Maximize the first resonance frequency of a plate.
RE: Maximize the first resonance frequency of a plate.
vidiii,
considering the shape of the mode of interest and the constraints you mentioned, I would suggest you to consider a plate with a C-shaped border frame; if this is not enough, I would also evaluate adding two diagonal ribs.
I think this is a tradeoff solution between the starting design and the pseudo-sandwitch solution proposed by BobM3.
Regards,
Spirit
'Ability is 10% inspiration and 90% perspiration.'
RE: Maximize the first resonance frequency of a plate.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.