March 10, 2014
The concept of the new “Dynamic Mechanical Yerzley Oscillograph – V” is based on the venerable “Advanced Yerzley Oscillograph – IV as per ASTM D945-16”. Both are based on weights on an oscillating beam always testing elastomers at the natural frequency of the configuration.
- AYO-IV has two possible moment arms, 5" or 10"; whereas, DMYO-V has a variable moment arm that automatically adjusts between 4" and 11". The weight table is motorized, it can setup automatically at any specified strain.
- DMYO-V has a load cell in addition to a displacement transducer. Both load and displacement are measured simultaneously, enabling:
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- The observation of the phase lag between Load and Displacement.
- The comparison of measured Phase Angle to the theoretically calculated (ASTM 5992) Loss Angle.
- The manual “Step Wise” hysteresis test of the AYO-IV is fully automated on the DMYO-V. The static hysteresis test is user-programmable and normally runs unattended on this test machine.
- The Dynamic Test on the DMYO-V is automated with a magnetic trigger, which enhances repeatability.
- The data processing and parameter evaluation procedures have been improved with noise elimination and data-smoothing algorithms.
- Minima and Maxima detection mechanisms use least square error curve fitting to improve accuracy. This is crucial for evaluating phase angles.
Applications
Automotive
- Automotive door seals: Dynamic Modulus (low values), Dynamic/Static Ratio of moduli (low values), help to design the automotive door seals correctly for better sound-proofing and longevity.
- Engine mounts: Yerzley Resilience (low values) and Yerzley Hysteresis (higher values) as well as Impact Energy (low values), Phase angle (high values) will absorb vibration energy much more efficiently for smooth riding.
- Windshield wipers: Dynamic Modulus (low values), Dynamic/Static Ratio of moduli (low values), helps to design the wipers correctly for better and long-term wiping function. Climate change (summer & winter) should have minimal effect on the wiping function.
Construction
Seismic Pads: Dynamic Modulus, Impact Energy, Phase angle all have to have high values for high damping function. Natural frequency around 5 to 9 Hertz may also be useful for the design criteria.