Example 11

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Mahes Rajakaruna
Beiträge: 9
Registriert: Fr 14. Jan 2011, 06:09
Wohnort: Australia

Example 11

Beitrag von Mahes Rajakaruna »

I am looking at the example file 11 (input file b17_g.cos)

A circular plate of radius of 1000mm has a pressure of 2 N/mm2

The total force on the plate as pi*1000**2 * 2 = 6283185 N

From the output file z8804.txt the calculated sum of nodal forces is
sum F(1) = 0.25
sum F(2) = -1049.35
sum F(3) = -1580.9

I expected the sum F(3) to be equal to the total applied load for equilibrium. Why is this not so?

Beiträge: 60
Registriert: Fr 20. Nov 2009, 07:28

Beitrag von wehmann »

Dear Mr. Rajakaruna,

the sum F(1) of all nodes of the outer edge has to equal the applied load. The first degree of freedom will be the normal deflection/applied force, if you use plate elements. F(2) and F(3) are moments. It is important to use the values of the section "the nodal sums for each node". Select all values of the nodes of the outer edge and sum them, then you get the value 6.065E+6. This is not the exact value 6.283E+6 because the applied pressure loads are given to the edge nodes, too. But these nodes also have got the boundary condition u=0. This is why the pressure loads, given to these nodes, can not be received attention and the resulting force is less than 6.283E+6. I hope, your question is answered. If not, do not hesitate to ask again,

best regards

Christoph Wehmann