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Durability analysis on pre-constrained model

N/A

Hello,
I would like to medel the behaviour of a turbio diesel injector clam.
The clamp is like a 2 fingered fork, at he heel it rests on the cylinderhead,
at the fingers it holds the injector, and it is bolted at the middle into the cylinderhead.
Basically it is a 3 points bending problem.
I have a 31kN force coming from the bolt statically.
I would like to model the durability of this when the engine is running, from the
combustion chamber I will have about 500N coming upwards at each compression at
the injector/clamp contact area.
Is there a way to import the results of the static analysis (at 31kN), then add
dinamically the 500N? Or do I have to use a time-dependent load variation with an
offset of Clamp-reaction-force-at-injector and amplitude of 500N (Pi periodic)?

Thanks a lot for any help.
regards,
Tamas
1 REPLY

Re: Durability analysis on pre-constrained model

N/A

Hello Tamas,
If you plan to use SOL 112 or 109, you would want to create two loads for your transient
simulation. One load is the periodic loading, the other is the constant load. You
define each with a TLOAD that points to a table that gives the time history of the
loading. For the constant one, I recommend ramping the load up to the constant value
so you don't get a large initial transient from an instant application of a large
force. The periodic loading I would also start from the zero position. You will
want to run for several periods to get any transient effects to die out.
Alternatively to the ramp-up you may want to try the new transient initial conditions
that points to a static subcase IC(STATSUB) = n. The static subcase would be your
constant load. You would still need to define your constant load for the dynamic
subcase, but you would not have to ramp it up.
Remember for SOL 112, you probably want to use residual vectors.
Mark




"Tamas" wrote:
>
>Hello,
>
>I would like to medel the behaviour of a turbio diesel injector clam.
>
>The clamp is like a 2 fingered fork, at he heel it rests on the cylinderhead,
>at the fingers it holds the injector, and it is bolted at the middle into
>the cylinderhead.
>
>Basically it is a 3 points bending problem.
>
>I have a 31kN force coming from the bolt statically.
>
>I would like to model the durability of this when the engine is running, from
>the
>combustion chamber I will have about 500N coming upwards at each compression
>at
>the injector/clamp contact area.
>
>Is there a way to import the results of the static analysis (at 31kN), then
>add
>dinamically the 500N? Or do I have to use a time-dependent load variation
>with an
>offset of Clamp-reaction-force-at-injector and amplitude of 500N (Pi periodic)?
>
>
>Thanks a lot for any help.
>
>regards,
>Tamas
>