Deformation of polymer under pressure
Deformation of polymer under pressure
(OP)
Hello,
I want to put a disk of a certain polymer (let's say polypropylene) so that it can move along an axis inside a steel pressure tank, like a piston or syringe (see image attached). Above the disk there will be air and below it there will be water. When the system comes into balance (the tank will be connected to a pipeline with a certain manometric pressure of the pumps), the pressure in the air and water obviously will be the same. For a specific project the pressure of the water will be 30 bar, and therefore that of the air when the balance is reached (see image attached).
My question then is what's going to be the deformation of the disk because of this pressure from both sides inside the tank under normal operation (compression stress). I am afraid it could reduce its thickness and make it longer, "touching" the walls inside the tank (normally, the disk should not touch the walls so as to make the movement along the axis easier).
I have seen that the elasticity modulus might play a role, but would like confirmation of the formula I must use. The disk, for calculus assumptions, should be 50 mm thick.
Thanks!
Felipe
I want to put a disk of a certain polymer (let's say polypropylene) so that it can move along an axis inside a steel pressure tank, like a piston or syringe (see image attached). Above the disk there will be air and below it there will be water. When the system comes into balance (the tank will be connected to a pipeline with a certain manometric pressure of the pumps), the pressure in the air and water obviously will be the same. For a specific project the pressure of the water will be 30 bar, and therefore that of the air when the balance is reached (see image attached).
My question then is what's going to be the deformation of the disk because of this pressure from both sides inside the tank under normal operation (compression stress). I am afraid it could reduce its thickness and make it longer, "touching" the walls inside the tank (normally, the disk should not touch the walls so as to make the movement along the axis easier).
I have seen that the elasticity modulus might play a role, but would like confirmation of the formula I must use. The disk, for calculus assumptions, should be 50 mm thick.
Thanks!
Felipe





RE: Deformation of polymer under pressure
30 bar of hydrostatic pressure will have no measurable affect on the disk.
RE: Deformation of polymer under pressure
RE: Deformation of polymer under pressure
That is presuming that you use a HDPE, if is a plastic with lots of air in it then over time it will deform, perhaps distort, and become denser.
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P.E. Metallurgy, Plymouth Tube
RE: Deformation of polymer under pressure