ISO 18437-2:2005

Overview

ISO 18437-2:2005 specifies a resonance method to characterize the dynamic mechanical properties of visco‑elastic (resilient) materials used in vibration isolators. The standard defines laboratory measurements to obtain complex elastic properties (e.g., Young’s modulus and loss factor) across a frequency range relevant to shock and vibration systems - from very low frequencies up to about 20 kHz - and describes procedures to extend measured data via time‑temperature superposition.

Key topics and technical requirements

• Measurement principle: Resonance testing of bar or rod specimens to determine the complex Young’s modulus and loss factor (tan δ).
• Linearity: Tests assume linear vibrational behavior at small strain magnitudes; dynamic linearity checks are required.
• Specimen preparation:
  • Mould bar specimens (mould length ≥ 150 mm); typical trimmed length 100 mm ± 10 mm with square cross‑section ~6.0 mm or circular 6–8 mm diameter.
  • Acceptable specimen lengths from half to twice the nominal length.
• Test equipment (typical specifications):
  • Electro‑dynamic vibration generator: force > 5 N, peak displacement < 0.1 mm; drive frequency practical range often 25 Hz–10 kHz.
  • Matched accelerometers (or corrected pair): charge sensitivity > 1 pC/g.
  • Charge amplifiers (≥ 1 mV/pC) or pre‑amplified sensors.
  • Dual‑channel spectrum analyser: FFT, coherence, r.m.s. averaging, random noise excitation, resolution down to 0.1 Hz and dynamic range > 42 dB.
  • Environmental chamber: allows cooling below room temperature, controlled temperature steps (increase in 5 °C increments) and stability to about 0.5 °C.
• Data analysis:
  • Extraction of modulus and loss factor from resonance peaks.
  • Application of time‑temperature superposition and shift factors to build broad‑band frequency behavior (typically many decades of frequency at a reference temperature).
  • Reporting and presentation requirements for test data.

Applications and who uses it

ISO 18437-2:2005 is used by:

• Designers and engineers creating vibration isolators, mounts and shock mounts.
• Materials scientists and R&D teams selecting or developing visco‑elastic materials.
• Test laboratories performing dynamic mechanical analysis for product data sheets and quality control.
• Acoustic and structural engineers performing theoretical computations of vibration transfer or specifying damping materials.

Practical uses include material selection, isolator design optimization, theoretical transfer‑function calculations, product development, manufacturer product information, and production quality control.

Related standards

• ISO 18437 series (Part 3: Cantilever shear beam method; Part 4: Impedance method under preparation)
• Referenced documents: ISO 4664‑1, ISO 6721‑1, ISO 10112, ISO 10846‑1, ISO 23529, ISO 472, ISO 2041.

Keywords: ISO 18437-2:2005, resonance method, visco‑elastic materials, dynamic mechanical properties, vibration isolators, Young’s modulus, loss factor, time‑temperature superposition.