Pre-define Non-linear Materials in SAP2000:

• Use the SAP2000 interface to define the non-linear material properties for your elements (beams, columns, etc.)
• These materials can be assigned hysteresis models (e.g., Bilinear, Gap) with their respective parameters.
• Once defined, reference these materials within your MATLAB script using the element ID and material name when setting up the model through the API.

2. Utilize External Material Definition Files:

• SAP2000 allows defining non-linear material properties through external text files.
• You can use the MATLAB API to create these files with the desired parameters for the hysteresis models.
• Within SAP2000, you can then import these external material definition files and assign them to your elements.

3. Leverage Custom Functions (Limited Applicability):

• For specific, well-defined non-linear behaviors, you might explore developing custom functions within the SAP2000 Open System Extension (OSE).
• These functions could potentially handle some non-linear material behavior within the time history analysis. However, this approach requires advanced knowledge of SAP2000 OSE and may not be suitable for all scenarios.

Resources:

• While the official SAP2000 API documentation doesn't explicitly cover defining non-linear material properties, exploring the SAP2000 help files related to materials and time history analysis might offer some insights.
• Consider searching online communities like the MathWorks File Exchange (https://www.mathworks.com/matlabcentral/fileexchange/130864-dynamiclinear-seismic-analysis-2dframes) for user-developed functions that might bridge the gap between the API and non-linear material definition.