Specify a user-defined failure theory

This example shows how to specify your user-defined failure theory in the Laminate Modeler dialog box. In the Solid Laminate Modeler dialog box, you define the theory in the Ply Layup tab instead of the Laminate Properties and User Defined Failure Theories groups.

1. Code your custom failure theory functions in C++, C, or Fortran.Your failure theories can process ply stress or strain results that originate from Simcenter Nastran, MSC Nastran, ANSYS, and Abaqus. The stress and strain data can be nodal or elemental. For your theories, you can define equations for failure index, strength ratio, and margin of safety.

2. Compile your source code for your failure theories to get one or more DLL files.The interface for the DLL files is defined in the UserFailureTheoryApi.h file. This file is available in the following folder:[nx_installation_path]/nxcae_extras/laminate/UserFT/includeYou can find examples of C++ code, DLLs, and the XML file, and a PDF file that contains sample compilation instructions in the following folder:[nx_installation_path]/nxcae_extras/laminate/UserFT/examples

3. Create an XML file that contains user failure theory definitions. In the XML file, for each user defined failure theory, specify the following:The name of the theoryThe theory type: ply or interlaminarThe full path to the theory’s DLL fileThe format for the XML file is defined in a standard Document Type Definition (DTD) file. The DTD file and the XML file are available in the following folder:[nx_installation_path]/nxcae_extras/laminate/UserFT/xml

4. Start Simcenter 3D or NX.

5. Choose File→Utilities→Customer Defaults.

6. In the Customer Defaults dialog box, select Simulation→Pre/Post→Laminate Modeling.

7. On the General tab, in the User Defined Failure Theory XML Config File box, type the path and the name of the XML file.

8. Click OK.

9. Close and restart the software.

10. Open the FEM file with your laminate model and start Pre/Post.

11. Choose Laminate Physical Property .

12. In the Laminate Properties group, from the Ply Failure Theory or Interlaminar Failure Theory list, select User Defined.

13. In the User Defined Failure Theories group, from the Ply Failure Theory or Interlaminar Failure Theory list, select one of your theories.

14. Define the rest of your laminate.

15. Click OK.

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Specify a user-defined failure theory, Simcenter 3D 2021.1 Series

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