With this option, you may create your own user-defined constitutive model (UDM) for use in FLAC2D.
The main function of the constitutive model is to return new stresses, given strain increments. However, the constitutive model must also provide other information (such as name of the model and material property names) and describe certain details about how the model interacts with FLAC2D. This option is required to both load and run UDM models.
This option is required in order to run user constitutive models from Itasca’s online UDM Library.