Practical experience of minimum tension possible of a membrane

[pitchtwit]

I need to know a realistic minimum biaxial tension per unit length - in N/m - for the surface of a membrane which is 27.4 mm square - with surface density 0.0912 kg/m^2 - so that it could be vertical and remain tense so that mode shapes due incoming acoustic energy would remain intact (if the membrane goes too limp, the mode shapes will become distorted).

Also, the membrane must be able to remain stretched when a small central mass of 1 g is attached.

A realistic value from a paper I'm following uses 486.4 N/m, and I'd like to know if it can go as low as 2 N/m.

Basically at what tension will it become unacceptably limp?

Many thanks

 

[Greg Bernhardt]

I'm sorry you are not finding help at the moment. Is there any additional information you can share with us?

 

[pitchtwit]

Hi,

Well alternative values could be: -
Material: Polytherimide film
Density - 1200 kg/m^3
Young's Modulus, E = 3.6 GPa
Poisson's ratio, nu = 0.34
Membrane thickness = 0.076 mm
Original tension = 5.7 GPa
Circular membrane radius = 12 mm
Central mass weight = 1 g
Central mass radius = 2 mm

I'd just like to know approximately how low the tension of the membrane could go - taking into account gravity and the attached mass - before it would no longer act as a stretched membrane (i.e. vibrate in a predictable manner with modes of vibration, etc.).

A VERY rough idea would be fine.

Thanks