Please use .wbpz archive format for sharing your project files in student community. To do that, go to Workbench>Archive. 120 MB is the maximum file size that you can attach.
If the file size exceeds 120 MB, right click on Model or Mesh, and Clear Generated Data, to delete the mesh and the solution from the project. File>Save As a new name and then File>Archive to create a much smaller .wbpz file.
Vishal Ganore, ansys.com/student