Shear Stress on sleeve with grooves

In summary, the valve in the OP has a butterfly plate with an outer diameter of 3.90 inches and an effective length of 3.50 inches. There will be a slip fit between the sleeve and butterfly plate. A adhesive that has a bond strength of 2500 psi will be coated on the O.D. of the sleeve and inserted in the butterfly plate. The O.D. of the sleeve will be 0.415 and has 5 grooves width of the grooves is 0.05". The inlet air pressure of 45 psi will be applied to the valve.
  • #1
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1. There is a valve body in which there is a butterfly plate. A shaft goes through the butterfly plate allowing it to open and close. A sleeve is inserted into the I.D. of the butterfly plate that the shaft goes through. The I.D. of the hole (butterfly plate) that the sleeve is inserted is is 0.500 in. and the effective length the sleeve touches is 3.50 in. There will be a slip fit between the sleeve and butterfly plate. A adhesive that has a bond strength 2500 psi will be coated on the O.D. of the sleeve and inserted in the butterfly plate. The O.D of the sleeve will be 0.415 and has 5 grooves width of the grooves is 0.05". The inlet air pressure of 45 psi will be applied to the valve. The O.D. of the butterfly plate is 3.90 in.

2. σ = Load(lb)/Area3. What I have done so far is:
1) Load experienced on the whole plate, P = σ*Area = 45 psi * (3.90in)^2 * π/4) = 537 lb
2) Effect Area of adhesive on sleeve = 0.415in *π * 0.05in = 0.65 in^2
3) Calculate the pressure created on the sleeve
σ = 537lb/ 0.65 in^2 = 826 psi
4) Calculate the margin of safety from bond strength of adhesive
2500 psi / 826 psi = 3.02
I am not sure if this is correct though.

We know the sleeve cannot pull out or fallout. However, since there will be a torque created by the shaft opening or closing the butterfly plate, the sleeve is prone to spin freely if the adhesive deteriorates. The shaft is what rotates the butterfly plate. If there is torque created by the shaft and if the adhesive wore off then the sleeve MAY just spin around in the butterfly plate. I am not sure how to relate the torque to the bond strength of the adhesive.
 
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  • #2
It's hard to visualize the construction of this valve from a verbal description. Is there a diagram or figure which shows the construction that you can post?
 
  • #3
Here is a image! I hope this helps because I am stuck :(

309sbpy.jpg
 
  • #4
There will be two sleeves inserted. One on each end.
 
  • #5
wzzp144 said:
Here is a image! I hope this helps because I am stuck :(

309sbpy.jpg
The valve in the OP has an OD of 3.90 inches whereas the figure shows OD = 1.90 inches. Typo perhaps?
 
  • #6
Yes sorry that is type. it will be 3.90" Outer diameter of butterfly plate
 
  • #7
What am I missing here? The whole point of a butterfly valve in the first place is to avoid any torque on the actuating shaft. The torque on one wing of the plate is canceled out by the torque on the other wing.
 
  • #8
Well I am trying to relate the bond strength of the adhesive to the force or torque? Let's say by chance the adhesive were to wear or deteriorate, it may cause the sleeve to spin inside the butterfly plate then. There will be torque created by the shaft to open and close the plate with the addition of an inlet pressure of 45 psi.
 
  • #9
wzzp144 said:
There will be torque created by the shaft to open and close the plate with the addition of an inlet pressure of 45 psi.
That seems to be where the problem description and the solution attempt diverge.

Consider a view looking parallel to the shaft, as if you are looking down at the North pole. Due to the 45PSI you have some force applying a torque to the 'East' side of the butterfly. Also due to the 45PSI you have some force applying a torque to the 'West' side of the butterfly. Calculate the two torques and sum them, what due you get for the net torque?
 

1. What is shear stress on a sleeve with grooves?

Shear stress on a sleeve with grooves is the force that is applied parallel to the surface of the sleeve, which causes it to deform or slide along the grooves. It is a measure of the internal resistance of the sleeve to this force.

2. How is shear stress calculated on a sleeve with grooves?

Shear stress on a sleeve with grooves can be calculated by dividing the force applied parallel to the surface of the sleeve by the cross-sectional area of the sleeve. This will give the shear stress in units of force per area, such as pounds per square inch or newtons per square meter.

3. What factors affect the shear stress on a sleeve with grooves?

The factors that affect shear stress on a sleeve with grooves include the magnitude and direction of the force applied, the surface area of the sleeve, and the material properties of the sleeve such as its strength and elasticity.

4. Why are grooves sometimes added to sleeves?

Grooves are often added to sleeves to help distribute the shear stress more evenly along the surface of the sleeve. This can help prevent localized areas of high stress that could lead to failure or deformation of the sleeve.

5. How can the shear stress on a sleeve with grooves be reduced?

The shear stress on a sleeve with grooves can be reduced by increasing the surface area of the sleeve, using materials with higher strength and elasticity, and by distributing the force applied over a larger area, for example by using multiple grooves.

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