Structures vs Materials
Structures and materials often appear together and sometimes even used interchangeably. The main reason is that the boundary between structures and materials is not clear. Even our first solid mechanics course usually called either strength of materials or mechanics of materials is mainly talking about structures: rods, shafts, columns, beams, pressure vessels, etc. With the coming of composites, this difference between these two becomes even more elusive.
In my opinion, a material, specifically a structural material, is a substance structures can be made of. At least one of the dimensions of materials are not related with material properties. For example, the properties of material provided in bulky form are not related with any of its dimension. The properties of composites tapes are not related with its longitudinal length. Materials are shaped to a specific geometry to form structures.The behavior of structures depends not only on the material it is made of, but also depend on the specific geometry, and the support conditions and loading conditions.
I will appreciate any of your comments. Any suggestions for more concise and precise definition of materials are welcome. This differentiation is important is for our taxonomy as we have tools developed for modeling composite structures and tools for modeling composite materials.