ISO/TC 108/WG 28 - Vibration materials

ISO 18437-6:2017 specifies a standard method for the acquisition and analysis of data obtained using the test methods found in ISO 18437‑1 to ISO 18437‑5, ISO 6721‑4 to ISO 6721‑7 and ISO 6721‑12. ISO 18437-6:2017 is applicable to visco-elastic materials that are thermorheologically simple and that have been tested at equilibrium state for every temperature.

ISO 18437-1:2012 establishes the principles underlying ISO 18437-2 to ISO 18437-5 for the determination of the dynamic mechanical properties (i.e. elastic modulus, shear modulus, bulk modulus, loss factor, and Poisson ratio) of isotropic visco-elastic resilient materials used in vibration isolators from laboratory measurements. It also provides assistance in the selection of the appropriate part of this International Standard. ISO 18437-1:2012 is applicable to isotropic resilient materials that are used in vibration isolators in order to reduce: a) the transmissions of audio frequency vibrations to a structure that can, for example, radiate fluid-borne sound (airborne, structure-borne or other); b) the transmission of low frequency vibrations which can, for example, act upon humans or cause damage to structures or sensitive equipment when the vibration is too severe; c) the transmission of shock and noise. The data obtained with the measurement methods that are outlined in ISO 18437-1:2012 and further specified in ISO 18437-2 to ISO 18437-5 can be used for: 1) the design of efficient vibration isolators; 2) the selection of an optimum resilient material for a given design; 3) the theoretical computation of the transfer of vibrations through vibration isolators; 4) information during product development; 5) product information provided by manufacturers and suppliers; 6) quality control.

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, the term dynamic mechanical properties refers to the determination of the fundamental elastic properties, e.g. the complex Young modulus and Poisson ratio, as a function of temperature and frequency. ISO 18437-5:2011 is applicable to resilient materials that are used in vibration isolators in order to reduce: a) transmission of audio frequency vibrations to a structure, e.g. radiating fluid-borne sound (airborne, structure-borne, or other); b) transmission of low-frequency vibrations which can, for example, act upon humans or cause damage to structures or equipment when the vibration is too severe. The data obtained with the measurement methods that are outlined in ISO 18437-5:2011 and further detailed in ISO 18437-2 to ISO 18437-4 can be used for: 1) design of efficient vibration isolators; 2) selection of an optimum resilient material for a given design; 3) theoretical computation of the transfer of vibrations through isolators; 4) information during product development; 5) product information provided by manufacturers and suppliers; 6) quality control.

ISO 18437-4:2008 specifies a direct method for measuring the complex dynamic moduli of elasticity (the Young, shear and bulk moduli, and their respective loss factors corresponding to the tensile, shear and all compressive strains) for polymeric (rubbery and viscous polymers, as well as rigid plastics) materials over a wide frequency and temperature range. Measurements are performed by the dynamic stiffness method, which uses electric signals from sensors attached to a test piece. These signals are proportional to the dynamic forces acting on the test piece and the strains in the test piece due to the effect of these forces. The measurement frequency range is determined by the size of test piece, the accuracy required on the dynamic modulus measurements, the relationship between the stiffness of the oscillation generator and the stiffness of the test piece, and by the resonance characteristics of the test fixture used. The method presented in ISO 18437-4:2008 allows measurement under any static pre-load allowed for the test piece (including the test piece having the non-linear characteristics under different static loads), but under small dynamic (acoustic) strains, i.e. in limits where the linear properties of the test piece are not distorted. Depending on the pre-load conditions, the relation between the moduli is unique.

ISO 18437-2:2005 defines a resonance method for determining from laboratory measurements the dynamic mechanical properties of the resilient materials used in vibration isolators. It is applicable to shock and vibration systems operating from a fraction of a hertz to about 20 kHz. ISO 18437-2:2005 is applicable to resilient materials that are used in vibration isolators in order to reduce -- transmissions of unwanted vibrations from machines, structures or vehicles that radiate sound (fluid-borne, airborne, structure-borne, or other), and -- the transmission of low-frequency vibrations that act upon humans or cause damage to structures or sensitive equipment when the vibration is too severe. The data obtained with the measurement methods that are outlined in ISO 18437-2:2005 are used for -- the design of efficient vibration isolators, -- the selection of an optimum material for a given design, -- the theoretical computation of the transfer of vibrations through isolators, -- information during product development, -- product information provided by manufacturers and suppliers, and -- quality control.

ISO 18437-3:2005 defines a cantilever shear beam method for determining from laboratory measurements the dynamic mechanical properties of the resilient materials used in vibration isolators. Common errors due to clamping the specimen are avoided by using fixed ends so there is no rotational motion of the beam at its ends. This part of ISO 18437 is applicable to shock and vibration systems operating from a fraction of a hertz to about 20 kHz. ISO 18437-3:2005 is applicable to resilient materials that are used in vibration isolators in order to reduce -- transmissions of unwanted vibrations from machines, structures or vehicles that radiate sound (fluid-borne, airborne, structure-borne, or other), and -- the transmission of low- frequency vibrations that act upon humans or cause damage to structures or sensitive equipment when the vibration is too severe. The data obtained with the measurement methods that are outlined in ISO 18437-3:2005 are used for -- the design of efficient vibration isolators, -- the selection of an optimum material for a given design, -- the theoretical computation of the transfer of vibrations through isolators, -- information during product development, -- product information provided by manufacturers and suppliers, and -- quality control.