Group: Prof. Yu's Research Group in the Cloud ~ Blog: Blog

Blog

Structures vs Materials

Entry #39: 31 May 2014; 4:23 pm; 1 comments

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.

About the author

Wenbin Yu

Dr. Wenbin Yu, currently a Professor in School of Aeronautics and Astronautics at Purdue University, received his PhD in Aerospace Engineering from Georgia Tech in 2002. He is also the CTO of AnalySwift LLC and Director of the cdmHUB. His expertise is in micromechanics and structural mechanics with applications to composite/smart materials. He has authored over 150 refereed technical articles and developed several computer codes which are being extensively used in many government labs, universities, research institutes and companies. His research has been funded by both federal agencies and private industry. His recent honors include ASME Fellow, AIAA Associate Fellow, ASEE Outstanding New Mechanics Educator, Georgia Tech Outstanding Young Engineering Alumni, Utah Aerospace Engineering Educator of the Year, USU Technology Entrepreneur of the Year, USU College of Engineering Outstanding Researcher of the Year (twice), USU MAE 2006-2010 5-Year Outstanding Researcher, MAE Outstanding Researcher of the Year (thrice), MAE Outstanding Teacher of the Year, and Purdue University Scholar.

Comments on this entry

Wenbin Yu @ 11:59 am on 16 Jul 2014

In the book Micromechanics of Composite Materials by Jacob Aboudi et al, it has a good description regarding materials and structures, which are quoted here:

The difference between a structure and a material comes down to the presence of boundary. A material is a substance of which a body is composed. The material itself has no boundaries, but rather may be thought of as what is present at a point in the body. Scientist and engineers have developed ways to represent materials through properties that describe how the material behaves at a point in a body, such as Young's modulus, thermal conductivity, density, yield stress, Poisson's ratio, and coefficient of thermal expansion. The body itself, on the other hand, is a structure. It has boundaries and its behavior is dependent on the conditions at these boundaries. For example, a given a steel beam, the beam itself is a structure, while the material is steel. This distinction between materials and structures is natural and extremely convenient for structural engineers and materials scientists.

Reply Report abuse

Replying to Wenbin Yu
Comments

Post anonymously

Post a comment

Wenbin Yu @ 11:59 am on 16 Jul 2014

In the book Micromechanics of Composite Materials by Jacob Aboudi et al, it has a good description regarding materials and structures, which are quoted here:

The difference between a structure and a material comes down to the presence of boundary. A material is a substance of which a body is composed. The material itself has no boundaries, but rather may be thought of as what is present at a point in the body. Scientist and engineers have developed ways to represent materials through properties that describe how the material behaves at a point in a body, such as Young's modulus, thermal conductivity, density, yield stress, Poisson's ratio, and coefficient of thermal expansion. The body itself, on the other hand, is a structure. It has boundaries and its behavior is dependent on the conditions at these boundaries. For example, a given a steel beam, the beam itself is a structure, while the material is steel. This distinction between materials and structures is natural and extremely convenient for structural engineers and materials scientists.

Reply Report abuse