Engineering Mechanical Vibration Assignment Help

[ahbin98]

Homework Statement

For my part i needed to do calculation, but i dont know what calculation can be made.

Relevant Equations

I dont know :(

I just need any simple calculation that can be made, anyone who willing to help me out please contact me

 

[Lnewqban]

Welcome!
Are you given any data to perform such calculations?
How far should you go into designing that portable test bed?

 

[ahbin98]

Welcome!
Are you given any data to perform such calculations?
How far should you go into designing that portable test bed?

I only have the data of the engine like rpm and weight... The test bed design i think my friend are drawing it following the figure attached.. Another photo attached is the guide from my lecturer but i still don't understand.
Thanks for reply!

 

[Lnewqban]

The guidance of your lecturer seems very precise and easy to follow.
Please, take it easy and only try to apply the principles that you have learned to this particular case.

Basically, you need to calculate the energy, dead weight, accelerations and frequency that your flexible element has to withstand.
That element is going to absorb as much energy as possible, before it reaches the surface on which the base is placed on.

You can use springs and dampers, avoiding resonance.
You can also use rubber, which acts like a spring and a damper at once.

Just start working on what you know (or re-study what you should know by now) and show us your work, please.

 

[ahbin98]

The guidance of your lecturer seems very precise and easy to follow.
Please, take it easy and only try to apply the principles that you have learned to this particular case.

Basically, you need to calculate the energy, dead weight, accelerations and frequency that your flexible element has to withstand.
That element is going to absorb as much energy as possible, before it reaches the surface on which the base is placed on.

You can use springs and dampers, avoiding resonance.
You can also use rubber, which acts like a spring and a damper at once.

Just start working on what you know (or re-study what you should know by now) and show us your work, please.

I've been trying to read my slides for a week and i still can't figure it out :(
I don't know what data do i need and which formulae i need to use.
I think i only managed to figure out that the dry weight of the engine is 67.5KG, so i picked a anti-vibration mount(rubber) which has compression deflection of 20kg each and i need 4 of them, is it working that way?

 

[Lnewqban]

I've been trying to read my slides for a week and i still can't figure it out :(
I don't know what data do i need and which formulae i need to use.
I think i only managed to figure out that the dry weight of the engine is 67.5KG, so i picked a anti-vibration mount(rubber) which has compression deflection of 20kg each and i need 4 of them, is it working that way?

You will need to anchor a steel frame to the generator.
Then, you will locate and anchor four dampeners to and under that frame.
You will have a weight distribution that you can estimate for each damper.

Perhaps weight will be equally distributed, perhaps not, if you frame needs to have a handle and wheels.
You will need to add weight of frame.

Be careful about units, kilograms should be mass, not weight.
Perhaps the data is telling you 67 kilogram-force, which is an old technical unit?

The frequency to use may be the rpm's of the engine?

 

[ahbin98]

You will need to anchor a steel frame to the generator.
Then, you will locate and anchor four dampeners to and under that frame.
You will have a weight distribution that you can estimate for each damper.

Perhaps weight will be equally distributed, perhaps not, if you frame needs to have a handle and wheels.
You will need to add weight of frame.

Be careful about units, kilograms should be mass, not weight.
Perhaps the data is telling you 67 kilogram-force, which is an old technical unit?

The frequency to use may be the rpm's of the engine?

Sorry for late reply, been busy for other assignments lately.
To be honest, due to the pandemic of Covid-19 , we students did not really acquire the knowledge of this subject, so my lecturer told me, the calculation of how we choose the Anti-vibration mount is enough at today condition.
So i am trying to working out on some simple calculation but i wonder if it is correct. First image is the work I've done to calculate some simple data.
And then , i select a Anti-vibration mount which has compression load of 20kg, and from image 2, referring to M25, for line drew horizontally to the next graph, i obtained around 4.6mm static deflection, for line drew vertically down i can obtained 21 Hz interfering frequency. Does it work like this?