Calculating Rivet Pitch for Plate with 2500 N Load and 0.8 mm Thickness

In summary, the conversation discussed the problem of determining a suitable rivet pitch for attaching stringers to a plate in a structural design project. The structure is 1.5 meters long and 0.4 meters wide, and includes two ribs and eight stringers. The end plates will be open and there are restrictions on the design. The E modulus was given as 72400 MPa, and the thickness of the plate is 0.8 mm. The group is trying to calculate the maximum possible spacing between rivets to prevent inter-rivet buckling at 2.5 kN. However, there is some confusion about the calculation of the area of the plate and the end plates. The conversation also noted the importance of tying
  • #1
ozzolins
14
1
Hi guys!

I have assignments and we are trying to get to reasonable value for more than 2 days and still nothing...

Okay..

problem is:
https://imagizer.imageshack.us/v2/705x238q90/191/6qqd.png

picture of the plate:
https://imagizer.imageshack.us/v2/412x395q90/835/7u81.png

F = 2500 N (orthogonal to the plane)

Thickness is 0.8 mm

E modulus = 72400 MPa

K (0.9*c) = 1.89

We got Area with value of: 553812mm^2 = 0.5538 m^2


We keep getting value of 4.4 meters, isn't that too much?
 
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  • #2
Given that the structure is only 1.5 meters long and 0.4 m wide, yes, a rivet spacing of 4.4 m is too much.

You should show all of your detailed calculations.
 
  • #3
Here are the calculation steps:

https://imagizer.imageshack.us/v2/585x597q90/30/0jso.png

[I hope the step where I calculate area is straight-forward, it's just basic geometry]

E modulus was given in 72400 MPa, but it's the same as 72400 N/mm^2 right?
 
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  • #4
I don't understand your calculation of the area of the plate to be riveted.

I think you treat the area of plate at each end separately, which will give two different rivet pitch values.
You then select the smaller pitch value to use at both ends.

In any event, the lap width at one end is 65 mm and 110 mm at the sloped end. Remember, the rivets must resist tear out in shear, so the shear area involves the thickness of the plate being riveted, rather than the area of the overlap.
 
  • #5
Ok, I kind of gave you misleading info. I forgot to mention that in grey areas rivets cannot be placed because this box will be put into bending machine and in these places it will be clamped. Furthermore, there will be stringers inside the box and rivets will be bolted through them (so in parallel to 1500mm side). So it would be like slightly simplified version of this (this is not our design, this is just for showing concept):

https://imagizer.imageshack.us/v2/499x462q90/23/lirr.png
Sorry, CATIA drawing is not ready yet.

We are planning to put 7-9 stringers in total and 2-3 ribs.

That is why I calculated the area of whole sheet face. But apparently area is the only value that can be wrong in my equation.
 
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  • #6
It's better if you can arrange your longitudinal stringers to have the same transverse spacing top an bottom. With that arrangement, you can tie the ends of the stringers together to make a longitudinal frame. Similarly, you want to make the transverse frames supporting the top and bottom plates line up and tie together with the stringers supporting the side plates. Although the skin carries its share of the shear and bending loads, you want the stringers to tie together also so that they can support the plating effectively.

It's not clear from the drawings you have so far how the end plates join with the side plates of the top and bottom plates. Although it may not be desirable to locate rivets around the ends of the box, the plates must be joined together in some fashion.
 
  • #7
Well, we have some restrictions for this project so we decided to use two ribs (in the middle) and 8 stringers - in the corners between plates and 2x2 stringers on top and bottom plates as shown in picture. Box ends will be open, so no plates there. But still question remains.. How to determine rivet pitch? Everything else seems ok. This is irritation design so we will be able to make changes afterwards if there are too many stringers, but river pitch must be calculated precisely cause we should prevent structure from inter rivet buckling at 2.5 kN.
 
  • #8
I guess what you are saying then, you want to know what rivet spacing would be suitable for attaching the stringers to the plating.

I'm not sure what 'irritation' design is. Perhaps you mean the design can go thru several 'iterations'.
 
  • #9
Exactly, I need max possible spacing between rivets for attaching stringers to the plate.

Sorry, yeah, that was a stupid typo. :D
 
  • #10
Please, anyone? Still trying to find out where my mistake is.
 

Related to Calculating Rivet Pitch for Plate with 2500 N Load and 0.8 mm Thickness

1. What is the purpose of determining rivet pitch?

The purpose of determining rivet pitch is to ensure the proper spacing between rivets in a structure or object. This is important for maintaining structural integrity and preventing failure.

2. How is rivet pitch determined?

Rivet pitch is determined by measuring the distance between the center of one rivet to the center of the next rivet. This measurement is typically taken in millimeters or inches.

3. What factors affect rivet pitch determination?

There are several factors that can affect rivet pitch determination, including the size and shape of the rivet, the material it is being used on, and the type of joint being created.

4. Why is it important to maintain a consistent rivet pitch?

Maintaining a consistent rivet pitch ensures that the load is evenly distributed across the structure or object. It also helps to prevent stress concentration and potential failure points.

5. What tools are used for determining rivet pitch?

There are various tools that can be used for determining rivet pitch, including rulers, calipers, and specialized rivet spacing tools. The choice of tool will depend on the specific application and accuracy needed.

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