Triangular plate stress calc. 3

[kb52]

We need to calculate the max stress on a triangular plate used in our assemblies. The plate is an isosceles triangle welded on all 3 edges to fill a gap. It is subjected to 7 bar pressure. Can anyone suggest a suitable calculation to use so we can avoid FEAing it

 

[bernoullies123]

Have a look at:

Roark’s Formulas for Stress and Strain 7th ed.

TABLE 11.4 Formulas for flat plates with straight boundaries and constant thickness

Case No. 18: Right-angle isosceles triangle; all edges simply supported
18a: Uniform over entire plate

The equations are quite simple.
i.e. Sigma (max) = 0.262qa^2/t^2 where q is the load, a is the height of the triangle, t thickness.

 

[boilerone]

Like Bernoullies123 says, the Roark's book already contains a lot of straight formulas for many special situations.

 

[kb52]

Thanks Bernoullies123 & Boilerone, however I have tried the Roark's formula and it gives a result several times greater than FEA. I suspect the problem is that the edges are fixed (i.e. welded) not simply supported

 

[prex]

Timoshenko and Krieger's Theory of Plates and Shells (the source for Roark's formulae) has also the case of an equilateral triangular plate with two or three edges clamped.
Of course I suppose you know that welded does not necessarily imply fixed.

prex

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