In addition to the native GoSimulate format, it is possible to load materials from two additional formats: Ansys and Solidworks. However, if you have a MatWeb account, you can choose from their extensive material collection and then export into either Ansys or Solidworks.
Please note: At the moment, GoSimulate only supports isotropic materials. Thus, for any anisotropic properties described in the non-native formats, GoSimulate will simply pick the first vectorial component.
To import a material file, click File->Load Material Library... under the Material tab (see image below). A file might contain one or several materials, which is the reason for the files being referred to as material libraries.
After choosing a library file, a dialog will show up asking you whether you want to replace the current library, or add the imported materials to the current library. You are also provided with the option to choose whether the resulting library should be loaded by default each time GoSimulate is started.
If you accidentally overwrite the default materials bundled with GoSimulate, you can always load these again by clicking File->Load bundled Materials.