shock absorber design

[nicola1985]

Hello, everyone!

I'm designing an assor for my first-level thesis. . .

I created almost the whole model for fem analysis but I have some problem with hypermesh.. .
use nastran as a solutor then work with nastran template.

In particular I would like to model a 300kg weight plate and go push my absorber with a certain speed towards a rigid wall.. .

I shaped the plate but I can't figure out how to establish the contact between the plate and the absorber (now it passes on) and how to put a concentrated mass at some point. . .

Thank you!

 

[MBT]

What does this have to do with mechanical design? ? ?
It's gonna be nastran stuff. .

 

[Fulvio Romano]

a first-level thesis with fem, dynamic analysis, contact analysis and non-linear impact theory.. . ?

Hopefully... :wink:

how to ask the school exam guide to go on two wheels. . .

 

[nicola1985]

Well, I quote your signature. .

 

[nicola1985]

The simulation is turning now...
for the contact I used rbe2 rigid connectors, while for the mass I solved giving a mass to all the knots of the plate behind the assor using conm2 elements.

Now you have to see the results!

 

[Fulvio Romano]

Well, I quote your signature. .

The simulation is turning now...
for the contact I used rbe2 rigid connectors, while for the mass I solved giving a mass to all the knots of the plate behind the assor using conm2 elements.

Now you have to see the results!

compliments for the intriguing. sincerely.

However, do not confuse courage with fearlessness.

 

[nicola1985]

compliments for the intriguing. sincerely.

However, do not confuse courage with fearlessness.

In fact I was a little temerary to accept a job of this kind but although I lost about 6 months (to learn to use a cad, a preprocessor and a solutor) I am happy because the theses should all be so...

in these 6 months I was intern at a company where they helped me and where in a few days we will build what was planned. . .

Thank you for your compliments!

in a few days I put the video on youtube and share them here!

Good weekend, everyone!

 

[Fulvio Romano]

In fact I was a little temerary to accept a job of this kind but although I lost about 6 months (to learn to use a cad, a preprocessor and a solutor) I am happy because the theses should all be so...

so, but above all. . .

in these 6 months I was intern at a company where they helped me and where in a few days we will build what was planned. . .

...so, history changes a lot.

I look forward to seeing the result and again congratulations :finger:

 

[Ing.Vedder]

I'm curious too, let us know and I join the compliments of lightning!

 

[nicola1985]

a little patience.. .I am engaged with the last exam!

 

[acatra83]

Hello nicola, aerospace engineer?

 

[acatra83]

a static analysis nastran for a dynamic simulation is not the maximum.. .
rbe2 contacts are rigid...so they are not well especially for absorbers. . .

use dyna

 

[nicola1985]

Hello nicola, aerospace engineer?

no meccanico...

a static analysis nastran for a dynamic simulation is not the maximum.. .
rbe2 contacts are rigid...so they are not well especially for absorbers. . .

use dyna

It's not a static analysis. . .

instead of putting rbe2 what should I put?stanno simulando un bullone.. .

 

[acatra83]

I don't know what you're doing. . .

You have to do a crash?with nastran?scusa but I don't understand. . .

cmq the bolts you can do them with elements like beam...

 

[nicola1985]

I don't know what you're doing. . .

You have to do a crash?with nastran?scusa but I don't understand. . .

cmq the bolts you can do them with elements like beam...

crash analysis...

I used the function of nastran "bolt" that schematizes a bolt like so many interconnected rbe2.

 

[Bradi88]

I'm working on such a problem... I'm using ls dyna pre post... and also as a solutor. . I learned to hate him. I have made 3 components: the wall, the assor and a plate. I'll explain. if you make the absorber impact back, as it is right that it is, immediately after the impact with the wall and therefore you cannot establish the extent of absorption. moving a wall against the assor is not perfectly correct as you do not take into account the mass of the machine to which the assor is attached. Therefore, it creates a rigid plate that has the mass that you want, and arrange it coincident to the back of the attenuator. set a rigid wall and a plastic kinematics for the attenuator. contacts impose them between plate and attenuator with a set part and a single surface automatic. the same you do with a set part between attenuator and wall.