Mechanical vibration and shock — Characterization of the dynamic mechanical properties of visco-elastic materials — Part 5: Poisson ratio based on comparison between measurements and finite element analysis

ISO 18437-5:2011 specifies two methods for estimating Poisson ratio or/and elastic modulus for isotropic visco-elastic or porous-elastic materials for use in linear finite element method (FEM) computer programs or other numerical approaches to vibrational or acoustic problems in visco-elastic structures of complicated geometry. The method is based on comparison between measurements of force-deflection or stiffness characteristics for disc-shaped specimens, with bonded boundary conditions at both ends, and FEM calculations of those conditions as a function of Poisson ratio. The choice of the single-sample or two-sample measurement method depends on whether the Poisson ratio is to be determined alone or together with the elastic modulus. Sometimes these materials are considered to be incompressible and behave non-linearly especially in large static deformations. Many commercial codes are available to solve such problems. This is not the case in ISO 18437-5:2011, where only small deformations observed in typical vibration problems are considered and, hence, linear FEM codes are adequate and more convenient.

For the purposes of ISO 18437-5:2011, and within the framework of ISO/TC 108,