random response analysis
Altair Employeehi sir,
these are different load collectoes defined in random response analysis tutorial they have explained about randps and tabrnd1 can u please tell what values are defined in other load collectors and they used two load steps(load1 and load 2) can u pls explain about that also??
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Answers
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RANDOM takes RANDPS. RANDPS takes loads (excited load and applied load... FRF) and TABRND1 which refer to power spectral data.
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they have defined total of 10 load collectors FREQ156, R , Rload2 , TABLE , SPC , force , FREQ 257 , DAREA2 what did they define in these load collectors ? why do we need force when we are defining psd??
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Jahnavi,
Can you share the video link?
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in that at 1:16:45 they did random respone analysis
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Jahnavi,
There are number of loadcollectors to define multiple loads. Load can be in any form, like velocity, load, acceleration etc...
The total PSD will be a sum of PSD responses of individual loads. These loads can be same or different.
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hi sir ,
In my problem i don't want to constraint my model, i want to give psd at some nodes allowing them single dof i.e base excitation
i have doubts at each step can u pls clarify them
my input is only acceleration psd or displacement psd over a range of frequencies
1. I will give only SPCD not spcs. in spcd what is that displacement mean? i want to change the displacements over a range on frequencies i.e psd.how can we give acclerations in spcd instead of displacement?
2. then a tabrnd1 is created. after that randps is created. what should be specified in J?? is that spcd??
3. what is the difference in acceleration given at spcd and tabrnd1??
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Jahnavi,
Displacement means enforcing the node to displace by a certain magnitude. In RLOAD you can change to Acceleration.
Since you have only one load specify the same for both J and K
If you have given a value of 5 in SPCD for instance, it will be used as a factor in tabrnd1.
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I want to accelerate 58 nodes in xyz direction as 1g,1g,1.5g.
I defined this acceleration through spcd card in one load collector only.
However if I changed the starting location of node for defining spcd my results are varying.
I have also used Tabled1 for defining acceleration in xyz direction.
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