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impulse response

durukanbdilek

hello I tried to obtain cantilever beam transient response to force - time curve, was given in attachment (finite element model also was given in attachment)

however I cannot obtain true displacement and acceleration response is zero

what is my mistake?

can you give any suggestion?

<?xml version="1.0" encoding="UTF-8"?>

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Altair Forum User

Hi,

Make the following changes to the table and try again:

<?xml version="1.0" encoding="UTF-8"?>

durukanbdilek

my purpose is to obtain time response according to force history via numerical analysis is it possible? or how to perform it ?

<?xml version="1.0" encoding="UTF-8"?>

also, I made changes you offered but I did not obtain any displacement

Altair Forum User

Hi @durukanbdilek

Sorry for a late reply.

You cannot use structural damping as it is for transient analysis. This has to be converted to viscous damping.

Use PARAM>>W3 to convert structural damping to viscous.

Please refer to OptiStruct help on how calculate W3 /emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' title=':)' width='20'>

durukanbdilek

ok, thnks for reply

namely

I cannot obtain this response when I apply force as above is true?

I cannot get damped free vibration response as above when I apply impulse force (as impact hammer) OK?

Altair Forum User

@durukanbdilek

What you see is absolute value and not a real value. Instead run modal transient analysis with TABLEDAMP and use ENFMOTN= REAL which converts absolute to real values.

durukanbdilek

mr pagadala, I clearly explain what I want;

I perform vibration test with impact hammer and accelerometers on laminate composite beam and plate specimens and I obtain time response (like damped free vibration response - as a attachment)