Natural Frequency of Elastic Pipe with Different Pressures

[Nefertiti]

Hi,

I have a 3mm diameter flexible silicone tube with wall diameter of 0.5mm. If this tube is filled with water at different pressures, how does the internal pressure present itself during modal testing (either shaker or impact testing). The tube lies on rigid table so it is completely supported from one side. I'm especially interested if there is relationship with natural frequency and the internal pressure.

 

[Nidum]

Think it through . What physical properties of the tube and water combination determine what the natural frequencies are going to be ?

How does changing the water pressure change these properties ? What is the effect of any changes of properties on the natural frequencies ?

 

[Nefertiti]

Hi,

Thanks Nidum. Correct if I’m wrong but essentially the water pressure makes the tube more rigid, i.e. change its elastic modulus (bending stiffness). This should affect the natural frequency so that increased pressure leads to increase in natural frequency.