#1 2023-03-16 23:37:41

jacob

Member

From: Dolní Benešov

Registered: 2022-03-07

Posts: 158

contact reaction force

Hello,
how to calculate reaction force from contact?

For force it is

reaction = POST_RELEVE_T(ACTION=_F(GROUP_NO=('target_bumper', ),
                                   INTITULE='reaction',
                                   NOM_CHAM='FORC_NODA',
                                   OPERATION=('EXTRACTION', ),
                                   RESULTANTE=('DX', 'DY', 'DZ'),
                                   RESULTAT=FORC))

But how to do that for contact?
I found that it should be done by VALE_CONT, but it doesn't exist.

mecour

Member

From: Ostrava (Czech)

Registered: 2011-04-04

Posts: 199

Re: contact reaction force

Hello,

postprocess field CONT_NOEU ?  doc u4.44.11 part 3.9.

mecour

jacob

Member

From: Dolní Benešov

Registered: 2022-03-07

Posts: 158

Re: contact reaction force

there is no part 3.9

However if you mean this:

#comment: conta = POST_RELEVE_T(ACTION=_F(GROUP_NO=('contact_tube', ),
#comment:                                 INTITULE='contact',
#comment:                                 NOM_CHAM='CONT_NOEU',
#comment:                                 OPERATION=('EXTRACTION', ),
#comment:                                 RESULTANTE=('RNY', ),
#comment:                                 RESULTAT=STA_NL))

Doesn't work

mecour

Member

From: Ostrava (Czech)

Registered: 2011-04-04

Posts: 199

Re: contact reaction force

Sorry chapter 3.6

Last edited by mecour (2023-03-18 07:10:03)

jacob

Member

From: Dolní Benešov

Registered: 2022-03-07

Posts: 158

Re: contact reaction force

there is nothing about computing sum of RN

mecour

Member

From: Ostrava (Czech)

Registered: 2011-04-04

Posts: 199

Re: contact reaction force

hello,

according to test file SDNV103a ( I just crated the group of node "Contact_N" - all nodes on contact face on part called VOL).

this gives me sum of reaction forces on the group Contact_N (field FORC_NODA does not exist on contact faces)

TABJEU=POST_RELEVE_T(ACTION=_F(INTITULE='MESSAGE',
                               GROUP_NO='Contact_N',
                               RESULTAT=RESU,
                               NOM_CHAM='REAC_NODA',
                               RESULTANTE=('DX' ,'DY' ,'DZ' , ) ,
                               OPERATION='EXTRACTION',),);

this gives me reaction forces on all nodes but exported separatelly for every node, you need for example some python function to compute the sum.

TABJEU=POST_RELEVE_T(ACTION=_F(INTITULE='MESSAGE',
                               GROUP_NO='Contact_N',
                               RESULTAT=RESU,
                               NOM_CHAM='CONT_NOEU',
                               NOM_CMP='RNZ',
                               OPERATION='EXTRACTION',),);

in both cases i obtained result 8.69E+03 (-8.69E+03 in CONT_NOEU case)

mecour

Last edited by mecour (2023-03-19 11:58:06)

jacob

Member

From: Dolní Benešov

Registered: 2022-03-07

Posts: 158

Re: contact reaction force

hello, yes I already figured that out (with help of chatGPT)
But why there is no build in function to compute sum?

conta2 = POST_RELEVE_T(ACTION=_F(GROUP_NO=('contact', ),

                                 INTITULE='contact',

                                 NOM_CHAM='CONT_NOEU',

                                 OPERATION=('EXTRACTION', ),

                                 RESULTAT=STA_NL,

                                 TOUT_CMP='OUI'))

---

Attachments:
RESULTS.zip, Size: 8.41 KiB, Downloads: 13

jacob

Member

From: Dolní Benešov

Registered: 2022-03-07

Posts: 158

Re: contact reaction force

another way is

conta1 = POST_RELEVE_T(ACTION=_F(GROUP_MA=('contact', ),

                                 INTITULE='contact',

                                 NOM_CHAM='CONT_NOEU',

                                 NOM_CMP=('RNZ', ),

                                 OPERATION=('MOYENNE_ARITH', ),

                                 RESULTAT=STA_NL))

and then multiply it by the number of nodes