Polyurethane/rubber coated transport roll design question

[kavkir]

Hallo everybody!

I have a task to calculate the thickness of the polyurethane or rubber coating to be applied to the steel core of a roll. The roll to be used to transport heavy pipes. The polyureathane liner will be casted over the steel body.

Could anyone suggest me what design criteria should I use for my FEA calculations? Should it be max. stresses in the PU material or shear stresses at the adhesive layer with the steel core?

The hyperelastic material model I have already.

Thanks in advance!

Regards,
Kavkir

 

[Kuzmicnr]

Hi Kavkir,

I'll take a shot at answering your question...

per the RMA Rubber Handbook, it sounds like your application would fall under 90 degree stripping for adhesion by vulcanization.(K11 or K21 ASTM call out) Providing the rubber compound selected is over 1500 psi tensile strength and 50 durometer Shore A or greater hardness, then one would expect 50 lbs./in. width minimum adhesion value. The ASTM recognized Testing method is D 429.

Your application sounds like the greatest challenge may be actually being able to get the rubber to flow properly in the mold to vulcanize the rubber to the substrate, depending on the design of the part.

Hope this helps, let me know if you have any other questions I'd be happy to help you out

Cheers

Nick Kuzmick
Timco Rubber Products
Cleveland OH
Website:

http://www.timcorubber.com

Linkedin:

http://www.linkedin.com/companies/368744/Timco+Rubber+Products?trk=pp_icon

 

[kavkir]

Thank you Nick for your answer.

Well, let say our manufacturer can reach a certain degree of adhesion and even further they can assure us that the interface stength is stronger than the liner itself, what design criteria could you suggest for the liner?
Would it be max. stretch or max. stress in the liner?

How do you choose the thickness of the rubber liner when
a client comes with a question to deliver a coated roller for a cetrtain load?

The problem in my case I can not oversize the roller since
there is no much space. I am talking about a huge roller of 500mm in diameter with load bearing capacity of 30 tonnes!

 

[Kuzmicnr]

Our approach, as the supplier of the finished part, when it comes to searching for these kind of answers is to get our rubber supplier involved along with the production manager, mold maker and the customer to address these types of issues.

We first ask for a drawing from the customer to begin and go from there. There very well may be limitations on the production floor, tooling design, and/or compound.
In the end, we focus on form, fit and function within the limitations of all parties.

I would suggest you address these issues accordingly, as each project has its own unique parameters.



Nick Kuzmick
Timco Rubber Products
Cleveland OH
Website:

http://www.timcorubber.com

Linkedin:

http://www.linkedin.com/companies/368744/Timco+Rubber+Products?trk=pp_icon

 

[MJFellow]

Hello Nick, I wonder whether you could help me. I have a silicon rubber seal for a window, A-A-59588A ASTM D412, where I can only find the tensile strength test allowable in Table 1 of the spec. Can I knock down by 60% to get the shear allowable.
You comment appreciated
PS:
Where can I download The RMA Rubber Handbook?

Regards
MJFellow

 

[GrahamBennett]

Here you go MJFellow:

https://www.rma.org/publications/epg_publications/index.cfm?PublicationID=11334

 

[MJFellow]

Thank you Graham