ISO 4965-2:2012

Overview

ISO 4965-2:2012 specifies the calibration procedure and instrumentation requirements for a Dynamic Calibration Device (DCD) used to measure forces in uniaxial fatigue testing. This part of ISO 4965 defines how to calibrate the DCD’s strain‑gauge bridge output conditioning and display electronics so that dynamic force measurements are traceable, accurate and valid over a defined frequency range. It complements ISO 4965-1, which describes the testing‑system calibration method using a calibrated DCD.

Key topics and technical requirements

• Scope and purpose: Calibration of DCD instrumentation to ensure accurate force measurement during dynamic (cyclic) uniaxial fatigue tests.
• Environmental requirement: Calibration performed at 18 °C to 28 °C (actual temperature reported in the report).
• DCD instrumentation: Reads/display DCD output as mV or mV/V; resolution must be ≤ 0.0001 mV/V.
• Dynamic voltage reference standard: Generates DC and sinusoidal waveforms (with configurable amplitude, frequency, DC offset and added harmonic distortion), traceable to national standards.
  • Expanded uncertainty of generated peak/valley voltages: ≤ 0.2% of the voltage range.
  • Example DC capability: for 10 V excitation, generate −20 mV to +20 mV with ≈20 µV uncertainty.
  • Output‑impedance mismatch between reference and DCD to be < 0.05% of the DCD instrumentation’s minimum input impedance.
• Calibration procedures:
  • DC calibration: warm up ≥30 min; generate nine DC voltages across the range (e.g., −2 to +2 mV/V → −20 to +20 mV at 10 V); record three repeated sets. DC pass limit: any single difference must not exceed 0.01 mV/V.
  • Sinusoidal calibration: warm up ≥30 min; use seven specified waveforms (various DC offsets and amplitudes); record peak and valley outputs at a minimum of three discrete frequencies per waveform; repeat with fixed total harmonic distortion (THD) of 0.125% ± 0.010%; generate required repeat sets.
• Acceptance criteria: For each waveform/frequency, peak and valley differences (relative to waveform amplitude) must be ≤ 0.5%. The valid frequency range is from DC up to the maximum frequency where all seven waveforms meet this limit.
• Reporting and traceability: Calibration report must include instrument IDs, reference standard, calibrated frequency range, energising voltage, output impedance, temperatures, organization, date and measured results. Maximum recommended re‑calibration interval: 26 months.

Applications and users

ISO 4965-2 is intended for:

• Fatigue testing laboratories performing uniaxial dynamic force calibrations.
• Metrology and calibration service providers that service DCDs and test instrumentation.
• Manufacturers of fatigue test frames, load cells, DCDs and signal conditioning electronics.
• Quality engineers ensuring traceable dynamic force measurement in materials testing and product validation.

Related standards

• ISO 4965-1: Dynamic force calibration - Testing systems (uses DCDs calibrated per ISO 4965-2).
• ISO 4965 (superseded): earlier consolidated version replaced by Parts 1 and 2.

Keywords: ISO 4965-2, dynamic force calibration, DCD instrumentation, uniaxial fatigue testing, sinusoidal calibration, DC calibration, dynamic voltage reference standard, calibration report.