Modelling viscoelastic material attachment
Modelling viscoelastic material attachment
(OP)
Hi,
I am trying to model a cylindrical casing with a neoprene sheet attached to it (through adhesive tape). Some masses are mounted on the neoprene intermittently, again with adhesive tape, with a hope of anchoring the neoprene.
Objective is to see how far the neoprene sheet and added masses would be effective in damping the vibration. As a first step I intend to see variation in strain energy in neoprene sheet in modal analysis step. I am using viscoelastic properties from a dynamic mechanical analysis test.
The problem I am finding is that elements where masses are mounted are severely distorted for any mode shape. And very low strain energy is developed in neoprene as compared to the base casing. I am using a 'tie' constraint to connect casing surface and neoprene surface and also that of neoprene and mass. Is this way of modelling correct and how to minimise element distortion ? I can understand that neoprene Young's modulus is very low as compared to steel masses, but is there any other way?
Thank you for your time and help.
Regards
mechie
I am trying to model a cylindrical casing with a neoprene sheet attached to it (through adhesive tape). Some masses are mounted on the neoprene intermittently, again with adhesive tape, with a hope of anchoring the neoprene.
Objective is to see how far the neoprene sheet and added masses would be effective in damping the vibration. As a first step I intend to see variation in strain energy in neoprene sheet in modal analysis step. I am using viscoelastic properties from a dynamic mechanical analysis test.
The problem I am finding is that elements where masses are mounted are severely distorted for any mode shape. And very low strain energy is developed in neoprene as compared to the base casing. I am using a 'tie' constraint to connect casing surface and neoprene surface and also that of neoprene and mass. Is this way of modelling correct and how to minimise element distortion ? I can understand that neoprene Young's modulus is very low as compared to steel masses, but is there any other way?
Thank you for your time and help.
Regards
mechie





RE: Modelling viscoelastic material attachment
Fig.1 - Total assembly strain map in a mode shape
Fig.2 - Only neoprene sheet with its distorted elements at the location of mass
RE: Modelling viscoelastic material attachment
And if your geometry is simple (cylindrical), why don't you make the nodes of steel+neoprene match, removing the need for the tie constraint?
RE: Modelling viscoelastic material attachment
Actually the masses being tuned masses (for a frequency), I would like to have them occupy the surface area for that mode shape at antinodes. I am really not sure if I can simply put a point mass at one FE node at each antinode of mode shape.
Can you please elaborate what you meant by matching the steel+neoprene nodes? In fact during meshing I made sure they are matched node-to-node visually. But even then we have to define a constraint. Right? Otherwise how they will remain attached?
Kind regards