How can extract the mass, stiffness and structural damping matrices from a .bdf file?

Hi,

I need to extract the mass, stiffness and damping structural matrices from a .bdf files. Normally I just needed to add the following lines after BEGIN BULK in the .bdf file to get that:

"PARAM,EXTOUT,DMIGPCH"

"PARAM,COUPMASS,1"

Unfortunately when I'm trying to get that, Nastran is not able to create the .pch file where all information related to the matrices are stored.

So, How can I solve this problem? Is needed to add some addicional information inside to the .bdf file?

Thank you for your support

Parents

0 Don.Graff over 5 years ago

When it is necessary to send us models, it is probably best to open a customer support case, rather than posting the model on this public forum.

I ran your input file and see that there is a FATAL error- always check the f06 for errors. This FATAL is due to have MAT1 with an id of '1' twice in the input file. If you change one of them (and the corresponding PSHELL that uses it) to a new id, it should run.

I changed:

$ Material Record: Glass

MAT1   1      6.6+10         .21    2500.                  .01

$ Elements and Element Properties for Section: Mat1_01

$ This PSHELL entry was generated from the following Apex objects

$ Apex Behavior: Apex Default Behavior

$ Apex Section: Mat1

$ Apex Material: Glass

PSHELL 463    1      1.-5   1              1

to:

$ Material Record: Glass

MAT1   2      6.6+10         .21    2500.                  .01

$ Elements and Element Properties for Section: Mat1_01

$ This PSHELL entry was generated from the following Apex objects

$ Apex Behavior: Apex Default Behavior

$ Apex Section: Mat1

$ Apex Material: Glass

PSHELL 463    2      1.-5   2              2
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0 Don.Graff over 5 years ago

When it is necessary to send us models, it is probably best to open a customer support case, rather than posting the model on this public forum.

I ran your input file and see that there is a FATAL error- always check the f06 for errors. This FATAL is due to have MAT1 with an id of '1' twice in the input file. If you change one of them (and the corresponding PSHELL that uses it) to a new id, it should run.

I changed:

$ Material Record: Glass

MAT1   1      6.6+10         .21    2500.                  .01

$ Elements and Element Properties for Section: Mat1_01

$ This PSHELL entry was generated from the following Apex objects

$ Apex Behavior: Apex Default Behavior

$ Apex Section: Mat1

$ Apex Material: Glass

PSHELL 463    1      1.-5   1              1

to:

$ Material Record: Glass

MAT1   2      6.6+10         .21    2500.                  .01

$ Elements and Element Properties for Section: Mat1_01

$ This PSHELL entry was generated from the following Apex objects

$ Apex Behavior: Apex Default Behavior

$ Apex Section: Mat1

$ Apex Material: Glass

PSHELL 463    2      1.-5   2              2
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