Overview

The meaning of Non-Homogeneous in this book is that the quality of materials is different from place to place. As shown in Figure 1, in the two dimensional X-Y coordinate or three dimensional X-Y-Z coordinate, depending on the location, the material characteristics or failure stresses are different, therefore it is complex in nature. In the strength of materials, we call it Non-Homogeneous. It is well explained in Figures 1 and 2. Also the meaning of Anisotropic is the material characteristics such as the elastic constants or failure stresses are different depending on the geometric direction. As a good example of anisotropic material, we can look at the reinforced concrete. The concrete is strong in compressive stresses but very weak in tensile stresses. To overcome the weakness, we insert steel bars, the reinforcing bars are very strong in the tensile forces. In other words, in the direction of reinforcing bars, the materials are strong and in the other direction, they are weak in the tensile strength. These kind of materials are named as diversified or Anisotropic Materials. Now is the era of aviation and aeronautics. Huge passenger aircrafts can fly around the earth non-stop.