ISO 18437-4:2008

Overview

ISO 18437-4:2008 - Mechanical vibration and shock: Characterization of the dynamic mechanical properties of visco‑elastic materials - Part 4: Dynamic stiffness method specifies a direct test method to measure the complex dynamic moduli (Young, shear and bulk moduli) and their loss factors for polymeric materials (rubbery, viscous polymers and rigid plastics). The standard covers measurement over wide frequency and temperature ranges using the dynamic stiffness method, which converts sensor electrical signals into proportional force and strain data for the test piece.

Key topics and technical requirements

• Measured quantities: complex Young modulus (E*), shear modulus (G*), bulk modulus (K*) and corresponding loss factors (tan δ).
• Dynamic stiffness method: uses a displacement actuator and force transducer; electrical signals record dynamic force and strain.
• Small dynamic strains: measurements are performed within the linear visco‑elastic region (small amplitudes), though static pre‑load may be non‑linear.
• Frequency and temperature: the method supports broad frequency–temperature characterization and frequency‑temperature superposition (shift factors).
• Test-piece design: dimensions must ensure negligible inertial effects - the first eigenfrequency of the test piece should be about 3–5 times higher than the upper measurement frequency. Size and shape influence measurement range and accuracy.
• Setup and error control: requirements cover hardware, fixture resonance, relationship between generator stiffness and test-piece stiffness, conditioning (temperature, humidity, mechanical), and main error sources.
• Data processing and reporting: guidance on result presentation, superposition, and required test report content.

Applications and users

ISO 18437-4 is used where accurate dynamic mechanical characterization of visco‑elastic materials is needed:

• Design and modelling of vibration isolation and damping systems
• Acoustic material selection (absorption, transmission)
• R&D and material development for rubber, polymers and plastics
• Quality control and specification verification in automotive, aerospace, electronics, building and medical-device industries
• Test laboratories performing dynamic mechanical analysis and material property databases

Typical users: materials scientists, mechanical/acoustical engineers, test lab technicians, product designers and standards/compliance teams.

Related standards

• ISO 6721 series (dynamic mechanical properties of plastics)
• ISO 4664-1 (rubber dynamic properties guidance)
• ISO 10112 (graphical presentation of complex modulus)
• ISO 10846-1 (vibro‑acoustic transfer of resilient elements)
• ISO 23529 (preparing/conditioning rubber test pieces)

ISO 18437-4:2008 provides standardized, repeatable procedures for determining dynamic stiffness and loss behavior-essential input for accurate vibration, damping and acoustic engineering.