The situation is similar to bolted flanged joints where you need to calculate bolt pre-tightening load so as to achieve certain gasket pressure during operation.
One of the possible ways of solving your case would be-
1. Model need to include steel/graphite plates and tie-rods with brick/beam elements.
2. Model contact/gap elements between steel plates & graphite plates surface.
3. Simulate the tightening by tie-rods by giving negative temperature to tie-rod elements.
4. This fictitious temperature is to be arrived at by trial and error.
5. The final strain in the tie-rod elements should give rougly initial pressure required.
Hope this is useful.
Regards,
>>> "K.S. Raghavan" <[log in to unmask]> 2/5/2000 11:50:10 AM >>>
Hello Everybody,
I have a design cum analysis problem which is stated
below.
A stack consisting of several layers of flat
(graphite) plates is to be maintained at a
predetermined pressure.
This is done by by placing the graphite elements
betwen two steel plates which are guided by tie
rods.
The desired pressure is applied on these end plates
hydraukically. After the assembly is compressed
the end plates are held in position by tightening of
nuts and subsequently the hydraulic pressure is
removed.
The final equilibrium position of the assembly is
however affected by the elasticity of the tie rods
and also by the
tendency of the end plate to bow. As a result the
compressive pressure on the stack gets reduced from
the initially
applied value. Secondly due to bowing of the end
plates the grphite elements will experience
non-uniform
pressure distribution.
The design aspect of the problem is : How much
pressure is to be applied initially?
The analysis aspect of the problem is: Is there a
single step linear solution or is it to be solved
iteratively?
(Is the problem amenable to solution at all?)
Any ideas or suggestions?
Thanks and regards
(K.S.Raghavan)
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