I ask to my teacher about it. He said to me is impossible to find a material with such poisson ratios (I think a negative poisson ratio has no physical sense in fact), i.e. there is no material of poisson ratio of 0.5 in the Nature. Thus, the Elasticity Equations are given birth by the Nature, so that they cannot be used with any imaginary material.Poisson's Ratio is a material property that describes the relationship between the strain or deformation in the direction of an applied force and the strain or deformation in the perpendicular direction. It is denoted by the Greek letter "nu" (ν) and is defined as the negative ratio of transverse strain to axial strain.
Poisson's Ratio is an important parameter in materials science and engineering because it can provide insight into the mechanical properties and behavior of a material. It can also be used to predict how a material will deform under different types of loading conditions.
Poisson's Ratio has a theoretical limit of -1.0, meaning that the material would completely contract in one direction while being stretched in the other. However, in practical terms, most materials have a Poisson's Ratio between 0 and 0.5, with rubber and other highly flexible materials having values closer to 0.5.
Poisson's Ratio can be measured through various experimental techniques, such as tensile or compression testing, where the strain or deformation in both the axial and transverse directions can be recorded and compared. It can also be calculated using other material properties, such as Young's Modulus and shear modulus.
Yes, Poisson's Ratio can be changed through various methods, such as altering the microstructure of a material or applying external forces or stresses. For example, some materials can exhibit negative Poisson's Ratios, where they expand in the transverse direction when compressed in the axial direction, by incorporating specific arrangements of microstructural elements.