Cone paper stiffness?

[Dave Zan]

Anyone have any data on the stiffness of the paper used in a typical paper cone?
In particular the beam stiffness?
This data must exist somewhere for FEA analysis on cones but I haven't seen it.
Obviously varies with the paper thickness but also with the pulp treatment, whether it's pressed and so on.
I would like to find at least a ballpark number before I order some materials for an experiment.
American manufacturers (of course) use a non rational unit, the "Taber", why do they make life awkward?

David

 

[TBTL]

Paper (in general) has a Young's Modulus of around 2 GPa. To calculate the beam stiffness, you would also need the geometry.
Young's Modulus - Density
What is the young modulus of paper - Answers

 

[Dave Zan]

Paper...

Thanks, is this reasonable for speaker cone paper?
I know they typically beat the pulp and process in various ways.
What thickness would be reasonable?
Basically I hoped someone would have a value in Taber so I didn't have to do the calculation

Best wishes
David

 

[Boden]

Loudsoft (Peter Larssen) has built a cone material database in FineCone. I suppose you are familiar with this software suite. If not, just google.



You might ask Larssen to provide data. Maybe someone here on diya has acces to this database.


One issue I foresee is that cone paper comes in an endless variety of mixes, so it will hard to describe "cone paper" in terms of general material properties.


Keep us posted, it is a topic that I find rather fascinating. Unfortunately FineCone and PafSys are not affordable for the average amateur, so any of your ventures might be of great interest.



Eelco

 

[lowmass]

non-rational (not comparable) Contrary to reason; lacking an appropriate or sufficient reason; irrational. Lacking the ability to reason. (often philosophy) Not within the domain of what can be understood or analyzed by reason; outside the competence of the rules of reason.

Interesting how successful our irrationality has been

 

[Dave Zan]

non-rational (not comparable)...

The point is that the "Taber" unit is not comparable to any other unit of stiffness, or at least not easily and without arbitrary conversions.

...how successful our irrationality has been

This is like units, depends on how you define it.
If in terms of the health or development of the people then not so much.
But that's a can of worms for a different forum.

Best wishes
David

 

[Dave Zan]

Loudsoft (Peter Larssen) has built a cone material database in FineCone. I suppose you are familiar with this software suite...

Yes, it's what I had in mind when I wrote that the data must exist for FEA analysis on cones.

Maybe someone here on diya has acces to this database.

That was my hope.

One issue I foresee is that cone paper comes in an endless variety of mixes, so it will hard to describe "cone paper"...

Yes I mentioned the variability and it's also why I didn't just use non-specific "paper" properties.

Keep us posted, it is a topic that I find...

Hi Eelco, it interests me too and I will update you if I have any new information.
Do you have specific areas of interest?

Best wishes
David

 

[Boden]

Shape vs breakup modes. And, maybe more interesting: the impact of cone termination on break up behaviour.

Looking for doable mods a la dimpling, stiffening the cone-surround connection, surround mods etc.

What software do you intend to use for FEA?
Best,

Eelco

 

[Dave Zan]

..the impact of cone termination on break up behaviour.

I believe this is dominated by the surround properties, especially viscoelastic behaviour that is often far from simple quasi-static measured values.
So a lot of trial and error, even if one has FEA.

What software do you intend to use for FEA?

Not sure yet if it's very useful so I haven't looked too closely.
But it's axisymmetric so should be sufficiently simple for freeware/open source.

Best wishes
David

 

[Mattes]

Hi,


this is a very interesting theme, and especially, Eeelco, the shape-versus-breakup question has my full attention, joined by the termination/suspension theme, and of course shape/directionality, as well as angle between cone and coil former and partly cone decoupling for fullrange drivers...
Sadly, apart from spending 7 K€ for Finecone I haven´t found a solution yet.
Therefore I´m interested in any findings, too, and will of course report any success.


All the best


Mattes