Obtaining Mass and Stiffness Matrices from HyperMesh Model

Altair Forum User
Altair Forum User
Altair Employee
edited August 2021 in Community Q&A

I am looking to obtain the mass and stiffness matrices of Hypermesh models in order to manipulate them in Matlab for structural dynamics problems. Does anyone know of an output that Altair may have built in or possibly a simplified method of obtaining these? 

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2014

    Hi,

     

    Please use PARAM, EXTOUT in control cards to write out reduced stifness and mass matrix to an external file.

     

    EXTOUT has two formats DMIGPCH and DMIGBIN which wirtes to .pch and .dmg formats respectively.

     

    Go to Analysis>> Control cards>> PARAM, EXTOUT (DMIGPCH) to activate the card.

     

    This will write a reduced mass and stiffness matrices in .pch format in the working directory.

     

    You can also try PARAM, POST, -5  will write the stiffness and mass matrices to the .k.op2 and the .m.op2 files, respectively

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited November 2014

    Hi,

     

    where can I find this option in HyperCrash? Is there any possibility to get the nodal forces in an ASCII file?

    Thanks!

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2016

    Hi,

     

    I am facing the same problem. The method for calculating the .k.op2 and .m.op2 files seems the most straightforward to me. But how can I read obtained binary files?

     

    Thanks for you help,

    Matej

  • Rahul Rajan_21763
    Rahul Rajan_21763 New Altair Community Member
    edited May 2016

    You would need to open the result files (H3D/OP2) which are binary files in HV.

     

    Regards

    Rahul R

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited May 2016

    Can you please be more specific. How to view or load the mass and stiffness matrices, based on the op2 files in HV?

     

    Greetings,

    Matej

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited September 2016

    All,

     

    This feature maybe available soon for RADIOSS solver.

  • LOKESH KATARI
    LOKESH KATARI Altair Community Member
    edited September 2018

    how to calculate stiffness matrix of a body in HM opti

    thank you

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited September 2018

    Hi Lokesh,

     

    You can output the stiffness matrix. Please search for the same in the forum for related links. 

  • LOKESH KATARI
    LOKESH KATARI Altair Community Member
    edited September 2018

    can we calculate the rotational stiffness in hypermesh?

  • Diogo Ferreira
    Diogo Ferreira Altair Community Member
    edited December 2018

    I've done those steps and there's no file in working directory? why?

  • FaroukM
    FaroukM Altair Community Member
    edited April 2020
    Altair Forum User said:

    You would need to open the result files (H3D/OP2) which are binary files in HV.

     

    Regards

    Rahul R

     

    There is any other option to export *.m.op2 / *.k.op2 as an ASCI file ?

     

     

  • David Vásquez
    David Vásquez New Altair Community Member
    edited May 2021
    Altair Forum User said:

    Hi,

     

    Please use PARAM, EXTOUT in control cards to write out reduced stifness and mass matrix to an external file.

     

    EXTOUT has two formats DMIGPCH and DMIGBIN which wirtes to .pch and .dmg formats respectively.

     

    Go to Analysis>> Control cards>> PARAM, EXTOUT (DMIGPCH) to activate the card.

     

    This will write a reduced mass and stiffness matrices in .pch format in the working directory.

     

    You can also try PARAM, POST, -5  will write the stiffness and mass matrices to the .k.op2 and the .m.op2 files, respectively

    Hi, i tried both options but i only get the stiffness matrix, do you know why?

  • Vinícius Santos_20886
    Vinícius Santos_20886 New Altair Community Member
    edited August 2021
    Altair Forum User said:

    Hi,

     

    Please use PARAM, EXTOUT in control cards to write out reduced stifness and mass matrix to an external file.

     

    EXTOUT has two formats DMIGPCH and DMIGBIN which wirtes to .pch and .dmg formats respectively.

     

    Go to Analysis>> Control cards>> PARAM, EXTOUT (DMIGPCH) to activate the card.

     

    This will write a reduced mass and stiffness matrices in .pch format in the working directory.

     

    You can also try PARAM, POST, -5  will write the stiffness and mass matrices to the .k.op2 and the .m.op2 files, respectively

    Sorry, David Vásquez.

     

    But it did not work.

     

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