Various attempts have been made to correlate the bulk modulus of compound semiconductors and chalcopyrite compounds with many other physical parameters. Nevertheless, it is found that bulk modulus interconnected well with strength and hardness in many materials (Choi & Yu, 1996). Therefore, the material stiffness and its corresponding bulk modulus is one of the important […]
Category: ADVANCES IN COMPOSITE MATERIALS – ECODESIGN AND ANALYSIS
II-IV semiconductor compounds ZnX (X=S, Se, Te)
Covalent materials such as II-IV semiconductor compounds ZnX (X=S, Se, Te) have been extensively studied for their intrinsic structural, optical, and elastic properties such as energy gap, charge density, lattice constants and bulk modulus. However, bulk modulus has been found to correlate well with strength and hardness in many materials and those with largest bulk […]
Fiber reinforced composite materials
Under specific couplings of the elastic constants of orthotropic media, a very important family of orthotropic materials degenerates into the class of either transversely isotropic or isotropic media. Most of the engineering composites, especially fiber-reinforced, are of transversely isotropic media. Hence, for different composites, the norms are calculated for each material (Radwan, 1991) in Table […]
Applications
1.1 Piezoelectric semiconductors and ceramics Among semiconductor crystals, a family of wurtzite – type belongs to the 6mm class, which is piezoelectric active. The material properties (Tsai, 1992) and the norm calculations are in Table 1. From the table, the most piezoelectric effective among the five materials is CdS which has a very important feature […]
A proposed relation between the norm ratio and the anisotropy degree
It is known that the anisotropy of the material, i. e., the symmetry group of the material and the anisotropy of the measured property depicted in the same material may be quite different. Obviously, the property tensor must show, at least, the symmetry of the material. For example, a property which is measured in a […]
The concept of norm
The comparison of magnitudes of the norms can give valuable information about the origin of the physical property under examination. Since the norm is invariant in the material, the norm of a Cartesian tensor may be used as the most suitable representing and comparing the overall effect of a certain property of anisotropic materials of […]
Fourth rank tensors were introduced in specification of physical properties for several anisotropic media. A decomposition of these tensors into independent elementary tensors is undertaken, to offer valuable insight into the tensor structure. In an anisotropic material, the
elasticity symmetric tensor generally contains twenty-one non-zero distinct constants. When the material has some kind of symmetry, the number of these coefficients is reduced if the coordinate axes coincide with symmetry axes for the material. In analyzing the mechanical properties of anisotropic linear elastic medium, a tensor of fourth rank is required to make up […]
Third rank tensors
In the continuum approach to the study of anisotropic solids it is well known that certain physical properties can be represented by tensors. The polarization of a crystal produced by an electric field is an example of an anisotropic material property that is represented by tensors. If a stress is applied to certain crystals they […]
Second rank tensors
In the theory of linear elasticity, the relation between the stress and strain in a solid body is usually described by Hooke’s law which postulates a linear relation between the two. The stress – strain relations for elastic anisotropic material have not been very well established as compared to those of the isotropic material in […]
Form invariants and orthonormal basis elements
The decomposition methods of tensors have many applications in different subjects of engineering. In the mechanics of continuous media i. e. in elasticity studies; so far, the stress and strain tensors are decomposed into spherical (hydrostatic) and deviatoric parts, the hydrostatic pressure is connected to the change of volume without change of shape, whereas the […]